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Chakraborty B, González-Pinardo D, Fernández I, Phukan AK. Carbene-Decorated Geometrically Constrained Borylenes for Bond Activations. Inorg Chem 2024; 63:14969-14980. [PMID: 39072652 DOI: 10.1021/acs.inorgchem.4c01697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
While metal-ligand cooperativity is well-known, studies on element-ligand cooperativity involving main group species are comparatively much less explored. In this study, we computationally designed a few geometrically constrained borylenes supported by different carbenes. Our density functional theory studies indicate that they possess enhanced nucleophilicity as well as electrophilicity, thus rendering them promising candidates for exhibiting borylene-ligand cooperativity. The cooperation between the boron and adjacent carbene centers facilitates different bond activation processes, including the cycloaddition of acetylene across the boron-carbene bond as well as B-H/Si-H bond activation reactions, which have been analyzed in detail. To the best of our knowledge, the borylenes proposed in this study represent the first examples of theoretically proposed geometrically constrained bis(carbene)-stabilized borylenes capable of cooperative activation of enthalpically strong bonds.
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Affiliation(s)
- Barsha Chakraborty
- Department of Chemical Sciences, Tezpur University, Napaam 784028, Assam, India
| | - Daniel González-Pinardo
- Departamento de Química Orgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Israel Fernández
- Departamento de Química Orgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Ashwini K Phukan
- Department of Chemical Sciences, Tezpur University, Napaam 784028, Assam, India
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2
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Fu K, Yang X, Yu Z, Song L, Shi L. Revealing the nature of covalently tethered distonic radical anions in the generation of heteroatom-centered radicals: evidence for the polarity-matching PCET pathway. Chem Sci 2024; 15:12398-12409. [PMID: 39118625 PMCID: PMC11304808 DOI: 10.1039/d4sc02602k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 06/27/2024] [Indexed: 08/10/2024] Open
Abstract
Recognition of the intermediacy and regulation of reactivity patterns of radical intermediates in radical chemistry have profound impacts on harnessing and developing the full potential of open-shell species in synthetic settings. In this work, the possibility of in situ formation of O/N-X intermediates from Brønsted base covalently tethered carbonyl hypohalites (BCTCs) for the generation of heteroatom-centered radicals has certainly been excluded by NMR experiments and density functional theory calculations. Instead, the spectroscopic analyses reveal that the BCTCs serve as precursors of tether-tunable distonic radical anions (TDRAs) which have been unequivocally substantiated to be involved in the direct cleavage of O/N-H bonds to generate the corresponding heteroatom-centered radicals. Meanwhile, a deep insight into the properties and reactivities of the resulting TDRAs indicates that the introduction of a tethered Brønsted base on the parent open-shell species reinforces their stabilities and leads to a reversal of electrophilicity. Moreover, the dual descriptor values and electrophilicity indices are calculated based on eleven reported radical reactions involving various electrophilic/nucleophilic radical species, further confirming their validity in the prediction of the polar effect and the polarity-matching consistency between nucleophilic TDRAs and protic O/N-H bonds. The additional halogen-free experiments mediated by the combination of phthaloyl peroxide and TEMPO also prove the feasibility of the TDRA-assisted philicity-regulation approach. Lastly, detailed intrinsic bond orbital (IBO) and Hirschfeld spin population analyses are employed to elucidate that the H-atom abstraction processes are the polarity-matching proton-coupled electron transfer (PCET) pathways, with a degree of oxidative asynchronicity.
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Affiliation(s)
- Kang Fu
- School of Chemistry and Chemical Engineering, School of Science(shenzhen), Harbin Institute of Technology Harbin 150001 China
| | - Xihui Yang
- School of Chemistry and Chemical Engineering, School of Science(shenzhen), Harbin Institute of Technology Harbin 150001 China
| | - Zhiyou Yu
- School of Chemistry and Chemical Engineering, School of Science(shenzhen), Harbin Institute of Technology Harbin 150001 China
| | - Lijuan Song
- School of Chemistry and Chemical Engineering, School of Science(shenzhen), Harbin Institute of Technology Harbin 150001 China
| | - Lei Shi
- School of Chemistry and Chemical Engineering, School of Science(shenzhen), Harbin Institute of Technology Harbin 150001 China
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3
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Ishida S, Yoshida Y, Iwamoto T. Metal-catalyzed valence isomerization of a methylene(thioxo)phosphorane to a thiaphosphirane. Chem Commun (Camb) 2024; 60:8288-8291. [PMID: 39016680 DOI: 10.1039/d4cc02147a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
We explored coordination chemistry associated with valence isomerization between a methylene(thioxo)phosphorane (MTP) and a thiaphosphirane. For this purpose, we developed the selective synthesis of a MTP by eliminating chlorodimethylphenylsilane from the corresponding chlorophosphine sulfide. Treatment of the MTP with an equivalent amount of pentafluorophenylgold(I) complex resulted in the formation of a thiaphosphirane gold(I) complex, which likely proceeds via an η2-P,C-MTP gold complex. The MTP undergoes a valence isomerization catalyzed by copper(I) chloride to furnish a transition metal-free thiaphosphirane. Computational studies proposed a plausible mechanism involving a Cu-assisted cyclization reaction.
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Affiliation(s)
- Shintaro Ishida
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
| | - Yusuke Yoshida
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
| | - Takeaki Iwamoto
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
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4
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Malcomson T, Rummel F, Barchenko M, O'Malley P. Hey ho, where'd the proton go? Final deprotonation of O6 within the S 3 state of photosystem II. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 257:112946. [PMID: 38843709 DOI: 10.1016/j.jphotobiol.2024.112946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/04/2024] [Accepted: 05/25/2024] [Indexed: 07/16/2024]
Abstract
The deprotonation of O6 within the S3 state marks the final deprotonation event before the formation of oxygen‑oxygen bond interactions and eventual production and release of dioxygen. Gaining a thorough understanding of this event, from the proton acceptors involved, to the exfiltration pathways available, is key in determining the nature of the resulting oxygen species, influencing the mechanism through which the first oxygen‑oxygen bond forms. Computational analysis, using BS-DFT methodologies, showed that proton abstraction by the local Glu189 residue provides consistent evidence against this being a viable mechanistic pathway due to the lack of a stable product structure. In contrast, abstraction via W3 shows an increasingly stable oxo-oxo product state between r[O5O6] = 2.1 Å & 1.9 Å. The resulting oxo-oxo state is stabilised through donation of β electron character from O6 to Mn1 and α electron character from O6 to O5. This donation from the O6 lone pair is shown to be a key factor in stabilising the oxo-oxo state, in addition to showing the initiation of first O5-O6 bond.
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Affiliation(s)
- Thomas Malcomson
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
| | - Felix Rummel
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Maxim Barchenko
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Patrick O'Malley
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
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5
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Kaya MO, Demirci T, Musatat AB, Özdemir O, Sönmez F, Kaya Y, Arslan M. Rabbit muscle pyruvate kinase activators: Synthesis, molecular docking and theoretical studies of N-substituted sulfonamide derivatives. Int J Biol Macromol 2024; 274:133184. [PMID: 38925176 DOI: 10.1016/j.ijbiomac.2024.133184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 06/01/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024]
Abstract
Pyruvate kinase (PK) activators have potential therapeutic applications in diseases such as sickle cell anemia. In this study, N-Substituted sulfonamide derivatives of 1,4-dihydropyridines were synthesized and evaluated as PK activators in vitro and using molecular docking studies. The compounds were synthesized by reacting dicarbonyl compounds with ammonium acetate, 5-nitrobenzaldehyde, and alumina sulfuric acid (ASA), followed by reduction and sulfonylation. The structures of the compounds were analyzed using spectroscopic techniques. DFT calculations provided insights into the electronic properties. Molecular docking of the compounds into the active site of PK showed favorable binding interactions. ADME evaluation indicated suitable solubility, BBB permeation, and lack of CYP450 inhibition. Overall, this study demonstrates the potential of new hybrid 1,4-dihydropyridine substituted sulfonamides as PK activators for further development. According to AC50 values, the compound (DTSF7, 0.97μM) is about 100-fold higher affective than the clinically used sulfonamide compound (AC50 = 90μM) for PK.
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Affiliation(s)
- Mustafa Oğuzhan Kaya
- Chemistry, Faculty of Arts and Science, Kocaeli University, 41001 Kocaeli, Turkey.
| | - Tuna Demirci
- Scientific and Technological Research Laboratory, Düzce University, 81620 Düzce, Turkey
| | | | - Oğuzhan Özdemir
- Veterinary Science Department, Technical Sciences Vocational School, Batman University, 72000 Batman, Turkey
| | - Fatih Sönmez
- Pharmacy Services Department, Pamukova Vocational School, Sakarya University of Applied Sciences, 54900 Sakarya, Turkey
| | - Yeşim Kaya
- Chemistry, Faculty of Arts and Science, Kocaeli University, 41001 Kocaeli, Turkey
| | - Mustafa Arslan
- Chemistry, Faculty of Sciences, Sakarya University, 54050, Sakarya, Turkey
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6
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Sheong FK, Zhang JX, Lin Z. Fragment Aligned Molecular Orbital Analysis: An Innovative Tool for Analyzing Atypical Chemical Bonding. J Chem Theory Comput 2024. [PMID: 39046803 DOI: 10.1021/acs.jctc.4c00456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
In chemical research, it is a common practice to carry out quantum chemical calculations and analyze the canonical molecular orbitals (CMOs) obtained to study electronic structures of chemical systems. However, extensive orbital mixing of CMOs especially in molecular clusters significantly complicates our understanding of the electronic structures. In this paper, we have developed an innovative tool called fragment aligned molecular orbital (FAMO) analysis, which reconstructs our modular chemical picture by making use of the Procrustes analysis in statistical theory to align the occupied molecular orbitals of a molecular species against the occupied (molecular) orbitals of the constituting fragments of the cluster, and results in a set of chemically intuitive semilocalized orbitals. This alignment technique minimizes the extensive orbital mixing, thus allowing precise observation of bonding interactions in complex chemical systems. A few representative clusters have been selected as showcase examples to demonstrate the advantage of FAMO analysis in deciphering the distinct bonding interactions in cluster compounds.
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Affiliation(s)
- Fu Kit Sheong
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Jing-Xuan Zhang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
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7
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Leach IF, Klein JEMN. Oxidation States: Intrinsically Ambiguous? ACS CENTRAL SCIENCE 2024; 10:1406-1414. [PMID: 39071055 PMCID: PMC11273457 DOI: 10.1021/acscentsci.4c00825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 06/10/2024] [Accepted: 06/10/2024] [Indexed: 07/30/2024]
Abstract
The oxidation state ( OS ) formalism is a much-appreciated good in chemistry, receiving wide application. However, like all formalisms, limitations are inescapable, some of which have been recently explored. Providing a broader context, we discuss the OS and its interpretation from a computational perspective for transition metal (TM) complexes. We define a broadly applicable and easy-to-use procedure to derive OS s based on quantum chemical calculations, via the use of localized orbitals, dubbed the Intrinsic OS . Applying this approach to a cobalt complex in five OS s, isolated by Hunter and co-workers (Inorg. Chem.2021, 60, 17445), we find that the calculated Intrinsic OS matches the formal OS , consistent with the experimental characterization. Through analysis of the delocalized orbitals, the ligand field of the Co(III) complex is found to be "inverted", despite every cobalt-ligand bond being classically dative from the localized perspective-a bonding scenario very similar to that of [Cu(CF3)4]-. This is not atypical but rather a natural consequence of these metals bonding in the high-valent region, and we propose a more restrictive definition of (locally) inverted bonding. Additionally, two bonding descriptors within the Intrinsic Bonding Orbital (IBO) framework (σ-gain and π-loss) are introduced, which enable facile quantification of electron-sharing covalency across a broad range of TM complexes.
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Affiliation(s)
- Isaac F. Leach
- Molecular
Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 3, 9747
AG Groningen, The
Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
3, 9747 AG Groningen, The Netherlands
| | - Johannes E. M. N. Klein
- Molecular
Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 3, 9747
AG Groningen, The
Netherlands
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8
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Zhang C, Cummins CC, Gilliard RJ. Synthesis and reactivity of an N-heterocyclic carbene-stabilized diazoborane. Science 2024; 385:327-331. [PMID: 39024440 DOI: 10.1126/science.adp5749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 06/07/2024] [Indexed: 07/20/2024]
Abstract
Diazo compounds and organic azides are widely used as reagents for accessing valuable molecules in multiple areas of fundamental and applied chemistry. Their capacity to undergo versatile chemical transformations arises from the reactive nature of an incipient dinitrogen molecule at the terminal position. In this work, we report the synthesis and characterization of an N-heterocyclic carbene (NHC)-stabilized diazoborane-a boron-centered analog of organic azides and diazoalkanes. The diazoborane displays a strong tendency to release dinitrogen, thus serving as a borylene source, in analogy to organic azides and diazoalkanes serving as nitrene and carbene sources, respectively. Also reminiscent of diazoalkane and organic azide reactivity, the diazoborane serves as a 1,3-dipole that undergoes uncatalyzed [3+2] cycloaddition with an unactivated terminal alkyne, affording a five-membered heterocycle after a two-step rearrangement.
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Affiliation(s)
- Chonghe Zhang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Christopher C Cummins
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert J Gilliard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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9
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Franc M, Schulz J, Štěpnička P. Facile synthesis and bonding of 4-ferrocenyl-1,2,4-triazol-5-ylidene complexes. Dalton Trans 2024; 53:11445-11453. [PMID: 38904982 DOI: 10.1039/d4dt01433b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Ferrocene-substituted carbenes have emerged as attractive, redox-active ligands. However, among the compounds studied to date, ferrocenylated 1,2,4-triazol-5-ylidenes, which are closely related to the archetypal imidazol-2-ylidenes, are still unknown. Here, we demonstrate that the triazolium salt [CHN(Me)NCHN(Fc)]I (2; Fc = ferrocenyl), obtained by alkylation of 4-ferrocenyl-4H-1,2,4-triazole (1) with MeI, reacts selectively with metal alkoxide/hydroxide precursors [(cod)Rh(OMe)]2 and [(IPr)Au(OH)] (cod = cycloocta-1,5-diene, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) to produce the ferrocene-substituted 1,2,4-triazol-5-ylidene complexes [(cod)RhI{CN(Me)NCHN(Fc)}] and [(IPr)Au{CN(Me)NCHN(Fc)}]I in good yields. The complexes were characterised by NMR and IR spectroscopy, mass spectrometry, cyclic voltammetry, and single-crystal X-ray diffraction analysis. Density function theory (DFT) calculations were used to rationalise the electrochemical behaviour of the carbene complexes and to elucidate the bonding situation in these compounds. An analysis using intrinsic bond orbitals (IBOs) revealed that the 1,2,4-triazol-5-ylidene ligand exerted a strong trans influence and showed a synergistic stabilisation by the negative inductive and positive π-donor effects of the nitrogen atoms adjacent to the carbene carbon atom; these effects were enhanced by conjugation with the CHN bond at the exterior, similar to that in imidazol-2-ylidenes.
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Affiliation(s)
- Michal Franc
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
| | - Jiří Schulz
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
| | - Petr Štěpnička
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
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10
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Calderón-Rangel D, Rentería-Gómez Á, Cruz-Jiménez AE, Rentería Gómez MA, Jiménez-Halla JOC, Gámez-Montaño R. Ultrasound-assisted diastereoselective green synthesis of spiro-fused-γ-lactams functionalized with an amide bond heterocyclic bioisostere via the Ugi azide/domino process coupled strategy. Org Biomol Chem 2024; 22:5289-5295. [PMID: 38881431 DOI: 10.1039/d4ob00606b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
A series of linked-type 1,5-disubstituted tetrazoles (1,5-DS-Ts) were synthesised via an isocyanide-based multicomponent reaction (IMCR) and used as synthetic platforms to access bound-type polyheterocycles containing an epoxyisoindol-1(6H)-one scaffold under green conditions. This rapid sonochemical synthetic strategy includes a double domino process using an orthogonal heterocyclic input in the Ugi-azide (UA) reaction. DFT calculations and NBO analysis were performed to understand the pseudopericyclic reaction involved in the 1,5-electrocyclization of the UA mechanism.
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Affiliation(s)
- David Calderón-Rangel
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Col. Noria Alta, Guanajuato C.P. 36050, Gto., Mexico.
| | - Ángel Rentería-Gómez
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Col. Noria Alta, Guanajuato C.P. 36050, Gto., Mexico.
| | - Alicia E Cruz-Jiménez
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Col. Noria Alta, Guanajuato C.P. 36050, Gto., Mexico.
| | - Manuel A Rentería Gómez
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Col. Noria Alta, Guanajuato C.P. 36050, Gto., Mexico.
| | - J Oscar C Jiménez-Halla
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Col. Noria Alta, Guanajuato C.P. 36050, Gto., Mexico.
| | - Rocío Gámez-Montaño
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Col. Noria Alta, Guanajuato C.P. 36050, Gto., Mexico.
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11
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Zenner A, Steinmetzer J, Ueberschaar N, Freesmeyer M, Weigand W, Greiser J. The synthesis of N,1,4-tri(alkoxy-hydroxybenzyl)-1,4-diazepane-amines: investigations on reaction characteristics and mechanism. ROYAL SOCIETY OPEN SCIENCE 2024; 11:240293. [PMID: 39076358 PMCID: PMC11285842 DOI: 10.1098/rsos.240293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/26/2024] [Accepted: 05/07/2024] [Indexed: 07/31/2024]
Abstract
1,4-Diazepane-6-amine (DAZA) can be alkylated with three 2-hydroxybenzyl pendant arms, resulting in hexadentate chelators suitable for coordination of radiometals like 68Ga. These chelators, N,1,4-tri(alkoxy-2-hydroxybenzyl)-DAZA, can be produced via a one-pot synthesis, with the first step being a carbonyl amine condensation of DAZA with two respective 4-alkoxy-2-hydroxybenzaldehydes, followed by reductive amination with sodium borohydride. While the first step of this reaction is predictable, the subsequent reductive amination can result in either mono-, di- or tri(alkoxy-hydroxybenzyl)-DAZA compounds. Seeking to identify dependencies that might allow a specific reaction control towards the formation of either of the three possible products, and particularly towards the favoured trialkylated DAZA compounds, a variety of synthesis trials were performed. Additionally, computational methods were employed to evaluate the underlying reaction mechanism. Synthesis trials verified that the trialkylated DAZA compounds are formed via direct reductive amination of the dialkylated DAZA compounds. Subsequently, a synthetic method was established, leading to an increase in the percentage of the trialkylated DAZA compounds, which allowed the successful isolation of those hexadentate chelators. Additionally, an alternative pathway proceeding via aminal C-N bond insertion of an attacking third carbonyl moiety was evaluated by means of quantum chemical calculations but so far remains entirely hypothetical.
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Affiliation(s)
- Anne Zenner
- Working Group for Translational Nuclear Medicine and Radiopharmacy, Clinic of Nuclear Medicine, Jena University Hospital, Jena, Germany
| | - Johannes Steinmetzer
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Jena, Germany
| | - Nico Ueberschaar
- Mass Spectrometry Platform, Friedrich Schiller University Jena, Jena, Germany
| | - Martin Freesmeyer
- Working Group for Translational Nuclear Medicine and Radiopharmacy, Clinic of Nuclear Medicine, Jena University Hospital, Jena, Germany
| | - Wolfgang Weigand
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Jena, Germany
| | - Julia Greiser
- Working Group for Translational Nuclear Medicine and Radiopharmacy, Clinic of Nuclear Medicine, Jena University Hospital, Jena, Germany
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12
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Karnbrock SBH, Golz C, Alcarazo M. P(V)-bis(amidophenolate) ligand cooperation: stoichiometric CO-bond cleavage in aldehydes and ketones. Chem Commun (Camb) 2024; 60:6745-6748. [PMID: 38864327 DOI: 10.1039/d4cc02202e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
The cooperation between a geometrically constrained, highly electrophilic phosphorus(V) center, and an electronically rich tetradentate bis(amidophenolate) ligand enables the cleavage of the CO bond from typical aldehydes and ketones delivering iminio phosphoramidate species. The amphiphilic nature of these products, which is demonstrated through their reaction with typical Lewis acids and bases, enables their use as a mild source of silylium cations from silanes, allowing the selective reductive coupling of aldehydes to ethers under catalytic conditions.
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Affiliation(s)
- Simon B H Karnbrock
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstraße 2, 37077 Göttingen, Germany.
| | - Christopher Golz
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstraße 2, 37077 Göttingen, Germany.
| | - Manuel Alcarazo
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstraße 2, 37077 Göttingen, Germany.
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13
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Li L, Zhou Y, Xi Z, Guo Z, Duan JC, Yu ZX, Gao H. Desulfurdioxidative N-N Coupling of N-Arylhydroxylamines and N-Sulfinylanilines: Reaction Development and Mechanism. Angew Chem Int Ed Engl 2024; 63:e202406478. [PMID: 38637953 DOI: 10.1002/anie.202406478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 04/20/2024]
Abstract
A highly efficient and chemoselective approach for the divergent assembling of unsymmetrical hydrazines through an unprecedented intermolecular desulfurdioxidative N-N coupling is developed. This metal free protocol employs readily accessible N-arylhydroxylamines and N-sulfinylanilines to provide highly valuable hydrazine products with good reaction yields and excellent functional group tolerance under simple conditions. Computational studies suggest that the in situ generated O-sulfenylated arylhydroxylamine intermediate undergoes a retro-[2π+2σ] cycloaddition via a stepwise diradical mechanism to form the N-N bond and release SO2.
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Affiliation(s)
- Linwei Li
- School of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Ji'nan, 250100, Shandong, China
| | - Yi Zhou
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China
| | - Zhenguo Xi
- School of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Ji'nan, 250100, Shandong, China
| | - Zhaoquan Guo
- School of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Ji'nan, 250100, Shandong, China
| | - Ji-Cheng Duan
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China
| | - Zhi-Xiang Yu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China
| | - Hongyin Gao
- School of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Ji'nan, 250100, Shandong, China
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14
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Cheng YH, Ho YS, Yang CJ, Chen CY, Hsieh CT, Cheng MJ. Electron Dynamics in Alkane C-H Activation Mediated by Transition Metal Complexes. J Phys Chem A 2024; 128:4638-4650. [PMID: 38832757 PMCID: PMC11182348 DOI: 10.1021/acs.jpca.4c01131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 05/15/2024] [Accepted: 05/28/2024] [Indexed: 06/05/2024]
Abstract
Alkanes, ideal raw materials for industrial chemical production, typically exhibit limited reactivity due to their robust and weakly polarized C-H bonds. The challenge lies in selectively activating these C-H bonds under mild conditions. To address this challenge, various C-H activation mechanisms have been developed. Yet, classifying these mechanisms depends on the overall stoichiometry, which can be ambiguous and sometimes problematic. In this study, we utilized density functional theory calculations combined with intrinsic bond orbital (IBO) analysis to examine electron flow in the four primary alkane C-H activation mechanisms: oxidative addition, σ-bond metathesis, 1,2-addition, and electrophilic activation. Methane was selected as the representative alkane molecule to undergo C-H heterolytic cleavage in these reactions. Across all mechanisms studied, we find that the CH3 moiety in methane consistently uses an electron pair from the cleaved C-H bond to form a σ-bond with the metal. Yet, the electron pair that accepts the proton differs with each mechanism: in oxidative addition, it is derived from the d-orbitals; in σ-bond metathesis, it resulted from the metal-ligand σ-bonds; in 1,2-addition, it arose from the π-orbital of the metal-ligand multiple bonds; and in electrophilic activation, it came from the lone pairs on ligands. This detailed analysis not only provides a clear visual understanding of these reactions but also showcases the ability of the IBO method to differentiate between mechanisms. The electron flow discerned from IBO analysis is further corroborated by results from absolutely localized molecular orbital energy decomposition analysis, which also helps to quantify the two predominant interactions in each process. Our findings offer profound insights into the electron dynamics at play in alkane C-H activation, enhancing our understanding of these critical reactions.
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Affiliation(s)
| | | | - Chia-Jung Yang
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
| | - Chun-Yu Chen
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
| | - Chi-Tien Hsieh
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
| | - Mu-Jeng Cheng
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
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15
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Jung H, Choi J, Kim D, Lee JH, Ihee H, Kim D, Chang S. Photoinduced Group Transposition via Iridium-Nitrenoid Leading to Amidative Inner-Sphere Aryl Migration. Angew Chem Int Ed Engl 2024:e202408123. [PMID: 38871650 DOI: 10.1002/anie.202408123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 06/13/2024] [Accepted: 06/13/2024] [Indexed: 06/15/2024]
Abstract
We herein report a fundamental mechanistic investigation into photochemical metal-nitrenoid generation and inner-sphere transposition reactivity using organometallic photoprecursors. By designing Cp*Ir(hydroxamate)(Ar) complexes, we induced photo-initiated ligand activation, allowing us to explore the amidative σ(Ir-aryl) migration reactivity. A combination of experimental mechanistic studies, femtosecond transient absorption spectroscopy, and density functional theory (DFT) calculations revealed that the metal-to-ligand charge transfer enables the σ(N-O) cleavage, followed by Ir-acylnitrenoid generation. The final inner-sphere σ(Ir-aryl) group migration results in a net amidative group transposition.
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Affiliation(s)
- Hoimin Jung
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jungkweon Choi
- Center for Advanced Reaction Dynamics, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Daniel Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jeong Hoon Lee
- Center for Advanced Reaction Dynamics, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hyotcherl Ihee
- Center for Advanced Reaction Dynamics, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Dongwook Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Sukbok Chang
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
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16
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Snabilié DD, Ham R, Reek JNH, de Bruin B. Light Induced Cobalt(III) Carbene Radical Formation from Dimethyl Malonate As Carbene Precursor. Organometallics 2024; 43:1299-1307. [PMID: 38873572 PMCID: PMC11167645 DOI: 10.1021/acs.organomet.4c00127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/13/2024] [Accepted: 05/16/2024] [Indexed: 06/15/2024]
Abstract
Radical-type carbene transfer catalysis is an efficient method for the direct functionalization of C-H and C=C bonds. However, carbene radical complexes are currently formed via high-energy carbene precursors, such as diazo compounds or iodonium ylides. Many of these carbene precursors require additional synthetic steps, have an explosive nature, or generate halogenated waste. Consequently, the utilization of carbene radical catalysis is limited by specific carbene precursors that access the carbene radical intermediate. In this study, we generate a cobalt(III) carbene radical complex from dimethyl malonate, which is commercially available and bench-stable. EPR and NMR spectroscopy were used to identify the intermediates and showed that the cobalt(III) carbene radical complex is formed upon light irradiation. In the presence of styrene, carbene transfer occurred, forming cyclopropane as the product. With this photochemical method, we demonstrate that dimethyl malonate can be used as an alternative carbene precursor in the formation of a cobalt(III) carbene radical complex.
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Affiliation(s)
- Demi D. Snabilié
- Van ‘t Hoff Institute
for Molecular Sciences, University of Amsterdam,
Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Rens Ham
- Van ‘t Hoff Institute
for Molecular Sciences, University of Amsterdam,
Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Joost N. H. Reek
- Van ‘t Hoff Institute
for Molecular Sciences, University of Amsterdam,
Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Bas de Bruin
- Van ‘t Hoff Institute
for Molecular Sciences, University of Amsterdam,
Science Park 904, Amsterdam 1098 XH, The Netherlands
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17
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Torić J, Karković Marković A, Mustać S, Pulitika A, Jakobušić Brala C, Pilepić V. Proton-Coupled Electron Transfer and Hydrogen Tunneling in Olive Oil Phenol Reactions. Int J Mol Sci 2024; 25:6341. [PMID: 38928048 PMCID: PMC11203655 DOI: 10.3390/ijms25126341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
Olive oil phenols are recognized as molecules with numerous positive health effects, many of which rely on their antioxidative activity, i.e., the ability to transfer hydrogen to radicals. Proton-coupled electron transfer reactions and hydrogen tunneling are ubiquitous in biological systems. Reactions of olive oil phenols, hydroxytyrosol, tyrosol, oleuropein, oleacein, oleocanthal, homovanillyl alcohol, vanillin, and a few phenolic acids with a DPPH• (2,2-diphenyl-1-picrylhydrazyl) radical in a 1,4-dioxane:water = 95:5 or 99:1 v/v solvent mixture were studied through an experimental kinetic analysis and computational chemistry calculations. The highest rate constants corresponding to the highest antioxidative activity are obtained for the ortho-diphenols hydroxytyrosol, oleuropein, and oleacein. The experimentally determined kinetic isotope effects (KIEs) for hydroxytyrosol, homovanillyl alcohol, and caffeic acid reactions are 16.0, 15.4, and 16.7, respectively. Based on these KIEs, thermodynamic activation parameters, and an intrinsic bond orbital (IBO) analysis along the IRC path calculations, we propose a proton-coupled electron transfer mechanism. The average local ionization energy and electron donor Fukui function obtained for the phenolic compounds show that the most reactive electron-donating sites are associated with π electrons above and below the aromatic ring, in support of the IBO analysis and proposed PCET reaction mechanism. Large KIEs and isotopic values of Arrhenius pre-exponential factor AH/AD determined for the hydroxytyrosol, homovanillyl alcohol, and caffeic acid reactions of 0.6, 1.3, and 0.3, respectively, reveal the involvement of hydrogen tunneling in the process.
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Affiliation(s)
- Jelena Torić
- Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia; (J.T.); (A.K.M.); (S.M.)
| | - Ana Karković Marković
- Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia; (J.T.); (A.K.M.); (S.M.)
| | - Stipe Mustać
- Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia; (J.T.); (A.K.M.); (S.M.)
| | - Anamarija Pulitika
- Faculty of Chemical Engineering and Technology, University of Zagreb, 10000 Zagreb, Croatia;
| | - Cvijeta Jakobušić Brala
- Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia; (J.T.); (A.K.M.); (S.M.)
| | - Viktor Pilepić
- Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia; (J.T.); (A.K.M.); (S.M.)
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18
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Kadiyam RK, Sangolkar AA, Faizan M, Pawar R. Bispericyclic Ambimodal Dimerization of Pentafulvene: The Origin of Asynchronicity and Kinetic Selectivity of the Endo Transition State. J Org Chem 2024; 89:6813-6825. [PMID: 38661667 DOI: 10.1021/acs.joc.4c00186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The propensity of fulvenes to undergo dimerization has long been known, although the in-depth mechanism and electronic behavior during dimerization are still elusive. Herein, we made an attempt to gain insights into the reactivity of pentafulvene for Diels-Alder (DA) and [6 + 4]-cycloadditions via conventional and ambimodal routes. The result emphasizes that pentafulvene dimerization preferentially proceeds through a unique bifurcation mechanism where two DA pathways merge together to produce two degenerate [4 + 2]-cycloadducts from a single TS. Despite the [6 + 4]-cycloadduct being thermodynamically preferred, [4 + 2]-cycloaddition reactions are kinetically driven. Singlet biradicaloid is involved in through-space 6e- delocalization as a secondary orbital interaction that originates asynchronicity and stabilizes the bispericyclic transition state (TS). The transformation of various actively participating intrinsic bonding orbitals (IBOs) unambiguously forecasts the formation of multiple products from a single TS and rationalizes the mechanism of ambimodal reactions that are rather difficult to probe with other analyses. The changes in active IBOs clearly distinguish the conventional reactions from bifurcation reactions and can be employed to characterize and confirm the ambimodal mechanism. This report gains a crucial theoretical insight into the mechanism of bifurcation, the origin of asynchronicity, and electronic behavior in ambimodal TS, which will certainly be of enormous value for future studies.
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Affiliation(s)
- Rama Krishna Kadiyam
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana 506004, India
| | - Akanksha Ashok Sangolkar
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana 506004, India
| | - Mohmmad Faizan
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana 506004, India
| | - Ravinder Pawar
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana 506004, India
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19
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Vesseur D, Li S, Mallet-Ladeira S, Miqueu K, Bourissou D. Ligand-Enabled Oxidative Fluorination of Gold(I) and Light-Induced Aryl-F Coupling at Gold(III). J Am Chem Soc 2024. [PMID: 38607393 DOI: 10.1021/jacs.4c00913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
MeDalphos Au(I) complexes featuring aryl, alkynyl, and alkyl groups readily react with electrophilic fluorinating reagents such as N-fluorobenzenesulfonimide and Selectfluor. The ensuing [(MeDalphos)Au(R)F]+ complexes have been isolated and characterized by multinuclear NMR spectroscopy as well as X-ray diffraction. They adopt a square-planar contra-thermodynamic structure, with F trans to N. DFT/IBO calculations show that the N lone pair of MeDalphos assists and directs the transfer of F+ to gold. The [(MeDalphos)Au(Ar)F]+ (Ar = Mes, 2,6-F2Ph) complexes smoothly engage in C-C cross-coupling with PhCCSiMe3 and Me3SiCN, providing direct evidence for the oxidative fluorination/transmetalation/reductive elimination sequence proposed for F+-promoted gold-catalyzed transformations. Moreover, direct reductive elimination to forge a C-F bond at Au(III) was explored and substantiated. Thermal means proved unsuccessful, leading mostly to decomposition, but irradiation with UV-visible light enabled efficient promotion of aryl-F coupling (up to 90% yield). The light-induced reductive elimination proceeds under mild conditions; it works even with the electron-deprived 2,6-difluorophenyl group, and it is not limited to the contra-thermodynamic form of the aryl Au(III) fluoride complexes.
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Affiliation(s)
- David Vesseur
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069) , CNRS/Université Paul Sabatier , 118 Route de Narbonne, 31062 Toulouse, Cedex 09, France
| | - Shuo Li
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069) , CNRS/Université Paul Sabatier , 118 Route de Narbonne, 31062 Toulouse, Cedex 09, France
| | - Sonia Mallet-Ladeira
- Institut de Chimie de Toulouse (UAR 2599) , 118 Route de Narbonne, 31062 Toulouse, Cedex 09, France
| | - Karinne Miqueu
- E2S-UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM, UMR 5254), CNRS/Université de Pau et des Pays de l'Adour, Hélioparc, 2 Avenue du Président Angot, 64053 Pau, Cedex 09, France
| | - Didier Bourissou
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069) , CNRS/Université Paul Sabatier , 118 Route de Narbonne, 31062 Toulouse, Cedex 09, France
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20
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Araujo L, Fantuzzi F, Cardozo TM. Chemical Aristocracy: He 3 Dication and Analogous Noble-Gas-Exclusive Covalent Compounds. J Phys Chem Lett 2024; 15:3757-3763. [PMID: 38551487 PMCID: PMC11017316 DOI: 10.1021/acs.jpclett.4c00826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 03/23/2024] [Accepted: 03/25/2024] [Indexed: 04/12/2024]
Abstract
Herein, we predict the first set of covalently bonded triatomic molecular compounds composed exclusively of noble gases. Using a combination of double-hybrid DFT, CCSD(T), and MRCI+Q calculations and a range of bonding analyses, we explored a set of 270 doubly charged triatomics, which included various combinations of noble gases and main group elements. This extensive exploration uncovered nine noble-gas-exclusive covalent compounds incorporating helium, neon, argon, or combinations thereof, exemplified by cases such as He32+ and related systems. This work brings to light a previously uncharted domain of noble gas chemistry, demonstrating the potential of noble gases in forming covalent molecular clusters.
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Affiliation(s)
- Lucas Araujo
- Instituto
de Química, Universidade Federal
do Rio de Janeiro, Av. Athos da Silveira Ramos 149, Rio de Janeiro 21941-909, Brazil
| | - Felipe Fantuzzi
- School
of Chemistry and Forensic Science, University
of Kent, Park Wood Road, Canterbury CT2 7NH, U.K.
| | - Thiago M. Cardozo
- Instituto
de Química, Universidade Federal
do Rio de Janeiro, Av. Athos da Silveira Ramos 149, Rio de Janeiro 21941-909, Brazil
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21
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Zhang P, Yu ZX. Dynamically or Kinetically Controlled? Computational Study of the Mechanisms of Electrophilic Aminoalkenylation of Heteroaromatics with Keteniminium Ions. J Org Chem 2024; 89:4326-4335. [PMID: 38506441 DOI: 10.1021/acs.joc.3c02379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Quantum chemical calculations and molecular dynamics simulations were applied to study the electrophilic aminoalkenylation of heteroaromatics with keniminium ions. Post-transition state bifurcation (PTSB) was found in the electrophilic addition step for the aminoalkenylation of pyrroles and indoles, and the selectivity for these reactions was dynamically controlled. However, the aminoalkenylation of furan was kinetically controlled because no apparent PTSB was found in the electrophilic addition step. The substituents on the keteniminium ions can also affect the dynamic results for the aminoalkenylations to pyrroles: the C2-aminoalkenylated product is much more favored over the C3-aminoalkenylated product for keteniminium ions with electron-donating substituents, while the product ratio (C2 product/C3 product) decreased when stronger electron-withdrawing substituents were applied.
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Affiliation(s)
- Pan Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Zhi-Xiang Yu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
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22
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Hess KM, Leach IF, Wijtenhorst L, Lee H, Klein JEMN. Valence Tautomerism Induced Proton Coupled Electron Transfer:X-H Bond Oxidation with a Dinuclear Au(II) Hydroxide Complex. Angew Chem Int Ed Engl 2024; 63:e202318916. [PMID: 38324462 DOI: 10.1002/anie.202318916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/25/2024] [Accepted: 02/05/2024] [Indexed: 02/09/2024]
Abstract
We report the preparation and characterization of the dinuclear AuII hydroxide complex AuII 2(L)2(OH)2 (L=N,N'-bis (2,6-dimethyl) phenylformamidinate) and study its reactivity towards weak X-H bonds. Through the interplay of kinetic analysis and computational studies, we demonstrate that the oxidation of cyclohexadiene follows a concerted proton-coupled electron transfer (cPCET) mechanism, a rare type of reactivity for Au complexes. We find that the Au-Au σ-bond undergoes polarization in the PCET event leading to an adjustment of oxidation levels for both Au centers prior to C(sp3)-H bond cleavage. We thus describe the oxidation event as a valence tautomerism-induced PCET where the basicity of one reduced Au-OH unit provides a proton acceptor and the second more oxidized Au center serves as an electron acceptor. The coordination of these events allows for unprecedented radical-type reactivity by a closed shell AuII complex.
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Affiliation(s)
- Kristopher M Hess
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Isaac F Leach
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Lisa Wijtenhorst
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Hangyul Lee
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Johannes E M N Klein
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
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23
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Liu X, Wang F, Zhao Y, Azhati A, Wang X, Zhang Z, Lv X. First Principles Investigation of C, Cl 2 and CO Co-Adsorption on ZrSiO 4 Surfaces for Carbochlorination Reaction. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1500. [PMID: 38612015 PMCID: PMC11012826 DOI: 10.3390/ma17071500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/11/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024]
Abstract
The study of the adsorption behavior of C, CO and Cl2 on the surface of ZrSiO4 is of great significance for the formulation of the technological parameters in the carbochlorination reaction process. Based on first principles, the adsorption structure, adsorption energy, Barder charge, differential charge density, partial density of states and energy barrier were calculated to research the adsorption and reaction mechanism of C and Cl2 on ZrSiO4 surfaces. The results indicated that when C, CO and Cl2 co-adsorbed on the surface of ZrSiO4, they interacted with surface atoms and the charge transfer occurred. The Cl2 molecules dissociated and formed Zr-Cl bonds, while C atoms formed C1=O1 bonds with O atoms. Compared with CO, the co-adsorption energy and reaction energy barrier of C and Cl2 are lower, and the higher the C content, the lower the adsorption energy and energy barrier, which is beneficial for promoting charge transfer and the dissociation of Cl2. The 110-2C-2Cl2 has the lowest adsorption energy and the highest reaction activity, with adsorption energy and energy barriers of -13.45 eV and 0.02 eV. The electrons released by C are 2.30 e, while the electrons accepted by Cl2 are 2.37 e.
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Affiliation(s)
- Xingping Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; (X.W.); (Z.Z.)
- Xinte Energy Co., Ltd., Urmqi 830011, China; (Y.Z.); (A.A.)
| | - Fumin Wang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; (X.W.); (Z.Z.)
| | - Yalan Zhao
- Xinte Energy Co., Ltd., Urmqi 830011, China; (Y.Z.); (A.A.)
| | - Arepati Azhati
- Xinte Energy Co., Ltd., Urmqi 830011, China; (Y.Z.); (A.A.)
| | - Xingtao Wang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; (X.W.); (Z.Z.)
| | - Zhengliang Zhang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; (X.W.); (Z.Z.)
| | - Xueqian Lv
- Xinte Energy Co., Ltd., Urmqi 830011, China; (Y.Z.); (A.A.)
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24
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Dankert F, Hevia E. Synthesis and Modular Reactivity of Low Valent Al/Zn Heterobimetallics Supported by Common Monodentate Amides. Chemistry 2024; 30:e202304336. [PMID: 38189633 DOI: 10.1002/chem.202304336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 01/09/2024]
Abstract
Recent advances on low valent main group metal chemistry have shown the excellent potential of heterobimetallic complexes derived from Al(I) to promote cooperative small molecule activation processes. A signature feature of these complexes is the use of bulky chelating ligands which act as spectators providing kinetic stabilization to their highly reactive Al-M bonds. Here we report the synthesis of novel Al/Zn bimetallics prepared by the selective formal insertion of AlCp* into the Zn-N bond of the utility zinc amides ZnR2 (R=HMDS, hexamethyldisilazide; or TMP, 2,2,6,6-tetramethylpiperidide). By systematically assessing the reactivity of the new [(R)(Cp*)AlZn(R)] bimetallics towards carbodiimides, structural and mechanistic insights have been gained on their ability to undergo insertion in their Zn-Al bond. Disclosing a ligand effect, when R=TMP, an isomerization process can be induced giving [(TMP)2AlZn(Cp*)] which displays a special reactivity towards carbodiimides and carbon dioxide involving both its Al-N bonds, leaving its Al-Zn bond untouched.
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Affiliation(s)
- Fabian Dankert
- Department für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestraße 3, Bern, 3012, Switzerland
| | - Eva Hevia
- Department für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestraße 3, Bern, 3012, Switzerland
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25
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Deng CL, Hollister KK, Molino A, Tra BYE, Dickie DA, Wilson DJD, Gilliard RJ. Unveiling Three Interconvertible Redox States of Boraphenalene. J Am Chem Soc 2024; 146:6145-6156. [PMID: 38380615 DOI: 10.1021/jacs.3c13726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Neutral 1-boraphenalene displays the isoelectronic structure of the phenalenyl carbocation and is expected to behave as an attractive organoboron multi-redox system. However, the isolation of new redox states have remained elusive even though the preparation of neutral boron(III)-containing phenalene compounds have been extensively studied. Herein, we have adopted an N-heterocyclic carbene ligand stabilization approach to achieve the first isolation of the stable and ambipolar 1-boraphenalenyl radical 1•. The 1-boraphenalenyl cation 1+ and anion 1- have also been electrochemically observed and chemically isolated, representing new redox forms of boraphenalene for the study of non-Kekulé polynuclear benzenoid molecules. Experimental and theoretical investigations suggest that the interconvertible three-redox-state species undergo reversible electronic structure modifications, which primarily take place on the polycyclic framework of the molecules, exhibiting atypical behavior compared to known donor-stabilized organoboron compounds. Initial reactivity studies, aromaticity evaluations, and photophysical studies show redox-state-dependent trends. While 1+ is luminescent in both the solution and solid states, 1• exhibits boron-centered reactivity and 1- undergoes substitution chemistry on the boraphenalenyl skeleton and serves as a single-electron transfer reductant.
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Affiliation(s)
- Chun-Lin Deng
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kimberly K Hollister
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Andrew Molino
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086 Victoria, Australia
| | - Bi Youan E Tra
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - David J D Wilson
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086 Victoria, Australia
| | - Robert J Gilliard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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26
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Jörges M, Mondal S, Kumar M, Duari P, Krischer F, Löffler J, Gessner VH. Phosphinoyl-Substituted Ketenyl Anions: Synthesis and Substituent Effects on the Structural Properties. Organometallics 2024; 43:585-593. [PMID: 38425382 PMCID: PMC10900514 DOI: 10.1021/acs.organomet.3c00530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 03/02/2024]
Abstract
Ketenyl anions are versatile intermediates in synthetic chemistry and have recently become accessible as isolable reagents from metalated ylides by exchange of the phosphine with CO. Herein, we report on a systematic study of substituent effects on the structure and bonding situation in ketenyl anions. A series of phosphinoyl-substituted ketenyl anions {[R2P(X)CCO]- with X = O, NTol, S, Se} were prepared by carbonylation of the corresponding yldiides and isolated as their corresponding potassium salts. NMR and IR spectroscopic analyses together with computational studies demonstrate that the more electron-withdrawing oxo- and iminophosphinoyl substituents increase the s-character in the bond to the ketene moiety and hence the ynolate character of the anion. This trend is particularly seen in solution, whereas the solid-state properties are influenced by packing effects affecting the bonding situation.
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Affiliation(s)
- Mike Jörges
- Faculty of Chemistry and
Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | | | | | | | - Felix Krischer
- Faculty of Chemistry and
Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Julian Löffler
- Faculty of Chemistry and
Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Viktoria H. Gessner
- Faculty of Chemistry and
Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
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27
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Wang Y, Liu J, Sun W, Zhou Y, Wang X, Hu Q, Wen Z, Yao J, Li H. Oxygenation of Phenols with Water as the Oxygen Source and Oxoammonium Salt as the Oxidant. J Org Chem 2024; 89:2440-2447. [PMID: 38306296 DOI: 10.1021/acs.joc.3c02448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
Aromatic C-H oxygenation is important in both industrial production and organic synthesis. Here we report a metal-free approach for phenol oxygenation with water as the oxygen source using oxoammonium salts as the renewable oxidant. Employing this protocol, various alkyl-substituted phenols were converted into benzoquinones in yields of 59-98%. On the basis of 18O-labeling and kinetic studies, the hydroxy-oxoammonium adduct was proposed to attack the aromatic ring similarly to electrophilic aromatic substitution. We suppose that the findings described here not only provide an efficient and highly selective protocol for aromatic C-H oxygenation but also may encourage further developments of possible transition-metal-free catalytic methods.
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Affiliation(s)
- Yongtao Wang
- Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
- Center of Chemistry for Frontier Technologies, ZJU-NHU United R&D Center, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
| | - Jiaxin Liu
- Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
| | - Wenjing Sun
- Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
| | - Yujia Zhou
- Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
| | - Xinyu Wang
- Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
| | - Qixuan Hu
- Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
| | - Zeyu Wen
- Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
| | - Jia Yao
- Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
- Center of Chemistry for Frontier Technologies, ZJU-NHU United R&D Center, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
| | - Haoran Li
- Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
- Center of Chemistry for Frontier Technologies, ZJU-NHU United R&D Center, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China
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28
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Epping RF, de Zwart FJ, van Leest NP, van der Vlugt JI, Siegler MA, Mathew S, Reek JNH, de Bruin B. PhenTAA: A Redox-Active N 4-Macrocyclic Ligand Featuring Donor and Acceptor Moieties. Inorg Chem 2024; 63:1974-1987. [PMID: 38215498 PMCID: PMC10828995 DOI: 10.1021/acs.inorgchem.3c03708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 01/14/2024]
Abstract
Here, we present the development and characterization of the novel PhenTAA macrocycle as well as a series of [Ni(R2PhenTAA)]n complexes featuring two sites for ligand-centered redox-activity. These differ in the substituent R (R = H, Me, or Ph) and overall charge of the complex n (n = -2, -1, 0, +1, or +2). Electrochemical and spectroscopic techniques (CV, UV/vis-SEC, X-band EPR) reveal that all redox events of the [Ni(R2PhenTAA)] complexes are ligand-based, with accessible ligand charges of -2, -1, 0, +1, and +2. The o-phenylenediamide (OPD) group functions as the electron donor, while the imine moieties act as electron acceptors. The flanking o-aminobenzaldimine groups delocalize spin density in both the oxidized and reduced ligand states. The reduced complexes have different stabilities depending on the substituent R. For R = H, dimerization occurs upon reduction, whereas for R = Me/Ph, the reduced imine groups are stabilized. This also gives electrochemical access to a [Ni(R2PhenTAA)]2- species. DFT and TD-DFT calculations corroborate these findings and further illustrate the unique donor-acceptor properties of the respective OPD and imine moieties. The novel [Ni(R2PhenTAA)] complexes exhibit up to five different ligand-based oxidation states and are electrochemically stable in a range from -2.4 to +1.8 V for the Me/Ph complexes (vs Fc/Fc+).
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Affiliation(s)
- Roel F.
J. Epping
- Homogeneous,
Supramolecular Catalysis and Bio-Inspired Catalysis Group, van ’t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Felix J. de Zwart
- Homogeneous,
Supramolecular Catalysis and Bio-Inspired Catalysis Group, van ’t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Nicolaas P. van Leest
- Homogeneous,
Supramolecular Catalysis and Bio-Inspired Catalysis Group, van ’t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Jarl Ivar van der Vlugt
- Homogeneous,
Supramolecular Catalysis and Bio-Inspired Catalysis Group, van ’t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Maxime A. Siegler
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Simon Mathew
- Homogeneous,
Supramolecular Catalysis and Bio-Inspired Catalysis Group, van ’t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Joost N. H. Reek
- Homogeneous,
Supramolecular Catalysis and Bio-Inspired Catalysis Group, van ’t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous,
Supramolecular Catalysis and Bio-Inspired Catalysis Group, van ’t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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29
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Mandal M, Buss JA, Chen SJ, Cramer CJ, Stahl SS. Mechanistic insights into radical formation and functionalization in copper/ N-fluorobenzenesulfonimide radical-relay reactions. Chem Sci 2024; 15:1364-1373. [PMID: 38274066 PMCID: PMC10806759 DOI: 10.1039/d3sc03597b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 12/09/2023] [Indexed: 01/27/2024] Open
Abstract
Copper-catalysed radical-relay reactions that employ N-fluorobenzenesulfonimide (NFSI) as the oxidant have emerged as highly effective methods for C(sp3)-H functionalization. Herein, computational studies are paired with experimental data to investigate a series of key mechanistic features of these reactions, with a focus on issues related to site-selectivity, enantioselectivity, and C-H substrate scope. (1) The full reaction energetics of enantioselective benzylic C-H cyanation are probed, and an adduct between Cu and the N-sulfonimidyl radical (˙NSI) is implicated as the species that promotes hydrogen-atom transfer (HAT) from the C-H substrate. (2) Benzylic versus 3° C-H site-selectivity is compared with different HAT reagents: Cu/˙NSI, ˙OtBu, and Cl˙, and the data provide insights into the high selectivity for benzylic C-H bonds in Cu/NFSI-catalyzed C-H functionalization reactions. (3) The energetics of three radical functionalization pathways are compared, including radical-polar crossover (RPC) to generate a carbocation intermediate, reductive elimination from a formal CuIII organometallic complex, and radical addition to a Cu-bound ligand. The preferred mechanism is shown to depend on the ligands bound to copper. (4) Finally, the energetics of three different pathways that convert benzylic C-H bonds into benzylic cations are compared, including HAT/ET (ET = electron transfer), relevant to the RPC mechanism with Cu/NFSI; hydride transfer, involved in reactions with high-potential quinones; and sequential ET/PT/ET (PT = proton transfer), involved in catalytic photoredox reactions. Collectively, the results provide mechanistic insights that establish a foundation for further advances in radical-relay C-H functionalization reactions.
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Affiliation(s)
- Mukunda Mandal
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota 207 Pleasant Street SE Minneapolis MN 55455 USA
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Joshua A Buss
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Si-Jie Chen
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Christopher J Cramer
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota 207 Pleasant Street SE Minneapolis MN 55455 USA
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
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30
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Hu C, Wang XF, Li J, Chang XY, Liu LL. A stable rhodium-coordinated carbene with a σ 0π 2 electronic configuration. Science 2024; 383:81-85. [PMID: 38175894 DOI: 10.1126/science.adk6533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 11/20/2023] [Indexed: 01/06/2024]
Abstract
Isolable singlet carbenes have universally adopted a σ2π0 electronic state, making them σ-donors and π-acceptors. We present a rhodium-coordinated, cationic cyclic diphosphinocarbene with a σ0π2 ground state configuration. Nuclear magnetic resonance spectroscopy studies show a carbene carbon chemical shift below -30.0 parts per million. X-ray crystallography reveals a planar RhP2C configuration. Quantum chemical calculations rationalize how σ-electron delocalization/donation and π-electron negative hyperconjugation together stabilize the formally vacant σ orbital and the filled π orbital at the carbene center. In contrast to traditional carbene counterparts this carbene can undergo synthetic transformations with both a Lewis base and a silver salt, producing a Lewis acid/base adduct and a silver π-complex, respectively. Exhibiting ambiphilic reactivity, it can also form a ketenimine through reaction with an isocyanide.
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Affiliation(s)
- Chaopeng Hu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Xin-Feng Wang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Jiancheng Li
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Xiao-Yong Chang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Liu Leo Liu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
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31
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R D, Sengupta T, Kumar D, Khanna SN. Effect of Ligand Attachment at Ag 11 for CO Oxidation: A Computational Investigation. J Phys Chem A 2023; 127:10766-10774. [PMID: 38095876 DOI: 10.1021/acs.jpca.3c04675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Heterogeneous CO oxidation is a demanding reaction at room temperature due to the high activation energy required to break the O=O bond. While several metal clusters are reported to oxidize CO successfully, they fall short of their selectivity for the reaction and recyclability. In this regard, there is a need for economic catalysts with high catalytic activity, low activation barrier, and reusability. In this study, we have investigated the catalytic activity of the neutral pristine and ligated Ag11 cluster toward CO oxidation. We investigated the attachment effect of three organic donor ligands: trimethylphosphine, triethylphosphine, and N-ethyl pyrrolidone to the Ag11 cluster. Our results show that including donor ligands on the Ag11 cluster surface can significantly reduce the barrier heights for CO oxidation. The minimum barrier heights with the system coordinated with triethylphosphine showed the lowest activation barrier of 1.06 kcal/mol compared to the high activation barrier of 14.77 kcal/mol recorded for the pristine cluster. Exploration of the reaction mechanism and charge analysis showed that the electron donor ligands activate O2 via charge donation, thereby reducing the barrier heights of CO oxidation.
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Affiliation(s)
- Deeksha R
- Department of Chemistry, Faculty of Mathematical and Physical Sciences, M.S. Ramaiah University of Applied Sciences, Bengaluru, Karnataka 560058, India
| | - Turbasu Sengupta
- Physics Department, Virginia Commonwealth University, 701 W. Grace St., Richmond, Virginia 23284-2000, United States
| | - Deepak Kumar
- Department of Chemistry, Faculty of Mathematical and Physical Sciences, M.S. Ramaiah University of Applied Sciences, Bengaluru, Karnataka 560058, India
| | - Shiv N Khanna
- Physics Department, Virginia Commonwealth University, 701 W. Grace St., Richmond, Virginia 23284-2000, United States
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32
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Franc M, Vosáhlo P, Schulz J, Císařová I, Štěpnička P. Synthesis and reactivity of Pd(II) imidoyl complexes obtained by insertion of isocyanoferrocene into the Pd-C bonds of orthopalladated precursors. Dalton Trans 2023; 52:17701-17710. [PMID: 37830260 DOI: 10.1039/d3dt02717a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
While the multifaceted reactivity of organic isocyanides has been extensively demonstrated, that of their organometallic analogue, isocyanoferrocene (FcNC; Fc = ferrocenyl), has not yet been adequately explored. This contribution describes the syntheses of novel chelating Pd(II) imidoyl complexes, [(YCH2C6H4C(NFc)-κ2Y,C)PdCl(PR3)], by insertion of FcNC into the Pd-C bond of cyclopalladated precursors [(YCH2C6H4-κ2Y,C)PdCl(PR3)] (Y = Me2N, MeS, R = Ph, Me). The imidoyl complexes underwent facile alkylation with [Me3O][BF4] to produce the cationic aminocarbene complexes [{YCH2C6H4C(N(Me)Fc)-κ2Y,C}PdCl(PR3)][BF4]. All compounds were fully characterised using a combination of spectroscopic methods (NMR, FTIR and ESI MS), cyclic voltammetry and single-crystal X-ray crystallography. In addition, DFT calculations were used to describe the bonding in the two compound families. Analyses with intrinsic bond orbitals (IBOs) and the quantum theory of atoms in molecules (QTAIM) consistently pointed to the transformation of an X-type imidoyl C-ligand (σ-organyl) into an L-type carbene donor upon alkylation, which has only a minor structural consequence. Also reported is the unexpected conversion of the imidoyl complex [(Me2NCH2C6H4C(NFc)-κ2N,C)PdCl(PPh3)] into (Z)-2,2-dimethyl-1-(ferrocenylimino)isoindolin-2-ium tetrafluoroborate as a reductive elimination product, which was induced by Lewis and Brønsted acids.
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Affiliation(s)
- Michal Franc
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40, Prague, Czech Republic.
| | - Petr Vosáhlo
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40, Prague, Czech Republic.
| | - Jiří Schulz
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40, Prague, Czech Republic.
| | - Ivana Císařová
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40, Prague, Czech Republic.
| | - Petr Štěpnička
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40, Prague, Czech Republic.
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33
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Britto NJ, Sen A, Rajaraman G. Unravelling the Effect of Acid-Driven Electron Transfer in High-Valent Fe IV =O/Mn IV =O Species and Its Implications for Reactivity. Chem Asian J 2023; 18:e202300773. [PMID: 37855305 DOI: 10.1002/asia.202300773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/12/2023] [Accepted: 10/16/2023] [Indexed: 10/20/2023]
Abstract
The electron transfer (ET) step is one of the crucial processes in biochemical redox reactions that occur in nature and has been established as a key step in dictating the reactivity of high-valent metal-oxo species. Although metalloenzymes possessing metal-oxo units at their active site are typically associated with outer-sphere electron transfer (OSET) processes, biomimetic models, in contrast, have been found to manifest either an inner-sphere electron transfer (ISET) or OSET mechanism. This distinction is clearly illustrated through the behaviour of [(N4Py)MnIV (O)]2+ (1) and [(N4Py)FeIV (O)]2+ (2) complexes, where complex 1 showcases an OSET mechanism, while complex 2 exhibits an ISET mechanism, especially evident in their reactions involving C-H bond activation and oxygen atom transfer reactions in the presence of a Lewis/Bronsted acid. However, the precise reason for this puzzling difference remains elusive. This work unveils the origin of the perplexing inner-sphere vs outer-sphere electron transfer process (ISET vs OSET) in [(N4Py)MnIV (O)]2+ (1) and [(N4Py)FeIV (O)]2+ (2) species in the presence of Bronsted acid. The calculations indicate that when the substrate (toluene) approaches both 1 and 2 that is hydrogen bonded with two HOTf molecules (denoted as 1-HOTf and 2-HOTf, respectively), proton transfer from one of the HOTf molecules to the metal-oxo unit is triggered and a simultaneous electron transfer occurs from toluene to the metal centre. Interestingly, the preference for OSET by 1-HOTf is found to originate from the choice of MnIV =O centre to abstract spin-down (β) electron from toluene to its δ(dxy ) orbital. On the other hand, in 2-HOTf, a spin state inversion from triplet to quintet state takes place during the proton (from HOTf) coupled electron transfer (from toluene) preferring a spin-up (α) electron abstraction to its σ* (dz 2 ) orbital mediated by HOTf giving rise to ISET. In addition, 2-HOTf was calculated to possess a larger reorganisation energy, which facilitates the ISET process via the acid. The absence of spin-inversion and smaller reorganisation energy switch the mechanism to OSET for 1-HOTf. Therefore, for the first time, the significance of spin-state and spin-inversion in the electron transfer process has been identified and demonstrated within the realm of high-valent metal-oxo chemistry. This discovery holds implications for the potential involvement of high-valent Mn-oxo species in performing similar transformative processes within Photosystem II.
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Affiliation(s)
| | - Asmita Sen
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
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34
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Kumar S, Parameswaran P, Jana A, Jemmis ED. Lewis Acid Stabilized Diatomic Molecules of Group 14: A Computational Study on [(CO) 4Fe] 2E 2 (E = C, Si, Ge, Sn, Pb). J Phys Chem A 2023; 127:9442-9450. [PMID: 37931177 DOI: 10.1021/acs.jpca.3c04376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
A Lewis base and acid combination has been effectively employed to stabilize and isolate the low-valent group 14 compounds. We report DFT studies on stabilizing low-valent group 14 diatomics as adducts of Lewis acids employing transition metal carbonyl fragment iron tetracarbonyl [Fe(CO)4] as Lewis acid. Computational studies on [(CO)4Fe]2E2, E = C, Si, Ge, Sn, and Pb, predict five plausible isomers on its potential energy surface: linear (E2_L), bent (E2_B), three-membered (E2_T), dibridged (E2_D), and four-membered (E2_F). For the carbon analogue, the lowest energy configuration is linear and has a typical cumulenic structure, while silicon and germanium analogues favor three-membered cyclic isomers. Four-membered cyclic isomers are the most stable for tin and lead analogues.
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Affiliation(s)
- Sandeep Kumar
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore, 560012, India
| | - Pattiyil Parameswaran
- Department of Chemistry, National Institute of Technology Calicut, Kozhikode, 673601, Kerala, India
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500107, Telangana, India
| | - Eluvathingal D Jemmis
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore, 560012, India
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35
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Fuemmeler EG, Damle A, DiStasio RA. Selected Columns of the Density Matrix in an Atomic Orbital Basis I: An Intrinsic and Non-iterative Orbital Localization Scheme for the Occupied Space. J Chem Theory Comput 2023. [PMID: 37944142 DOI: 10.1021/acs.jctc.1c00801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
In this work, we extend the selected columns of the density matrix (SCDM) methodology [J. Chem. Theory Comput. 2015, 11, 1463-1469]─a non-iterative and real-space procedure for generating localized occupied orbitals for condensed-phase systems─to the construction of local molecular orbitals (LMOs) in systems described using non-orthogonal atomic orbital (AO) basis sets. In particular, we introduce three different theoretical and algorithmic variants of SCDM (referred to as SCDM-M, SCDM-L, and SCDM-G) that can be used in conjunction with the AO basis sets used in standard quantum chemistry codebases. The SCDM-M and SCDM-L variants are based on a pivoted QR factorization of the Mulliken and Löwdin representations of the density matrix and are tantamount to selecting a well-conditioned set of projected atomic orbitals (PAOs) and projected (symmetrically-) orthogonalized atomic orbitals, respectively, as proto-LMOs that can be orthogonalized to exactly span the occupied space. The SCDM-G variant is based on a real-space (grid) representation of the wavefunction, and therefore has the added flexibility of considering a large number of grid points (or δ functions) when selecting a set of well-conditioned proto-LMOs. A detailed comparative analysis across molecular systems of varying size, dimensionality, and saturation level reveals that the LMOs generated by these three non-iterative/direct SCDM variants are robust, comparable in orbital locality to those produced with the iterative Boys or Pipek-Mezey (PM) localization schemes, and completely agnostic toward any single orbital locality metric. Although all three SCDM variants are based on the density matrix, we find that the character of the generated LMOs can differ significantly between SCDM-M, SCDM-L, and SCDM-G. In this regard, only the grid-based SCDM-G procedure (like PM) generates LMOs that qualitatively preserve σ-π symmetry (in systems such as s-trans alkenes), and are well-aligned with chemical (i.e., Lewis structure) intuition. While the direct and standalone use of SCDM-generated LMOs should suffice for most chemical applications, our findings also suggest that the use of these orbitals as an unbiased and cost-effective (initial) guess also has the potential to improve the convergence of iterative orbital localization schemes, in particular for large-scale and/or pathological molecular systems.
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Affiliation(s)
- Eric G Fuemmeler
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Anil Damle
- Department of Computer Science, Cornell University, Ithaca, New York 14853, United States
| | - Robert A DiStasio
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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36
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Li B, Ju CW, Wang W, Gu Y, Chen S, Luo Y, Zhang H, Yang J, Liang HW, Bonn M, Müllen K, Goddard WA, Zhou Y. Heck Migratory Insertion Catalyzed by a Single Pt Atom Site. J Am Chem Soc 2023; 145:24126-24135. [PMID: 37867298 DOI: 10.1021/jacs.3c07851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Single-atom catalysts (SACs) have generated excitement for their potential to downsize metal particles to the atomic limit with engineerable local environments and improved catalytic reactivities and selectivities. However, successes have been limited to small-molecule transformations with little progress toward targeting complex-building reactions, such as metal-catalyzed cross-coupling. Using a supercritical carbon-dioxide-assisted protocol, we report a heterogeneous single-atom Pt-catalyzed Heck reaction, which provides the first C-C bond-forming migratory insertion on SACs. Our quantum mechanical computations establish the reaction mechanism to involve a novel C-rich coordination site (i.e., PtC4) that demonstrates an unexpected base effect. Notably, the base was found to transiently modulate the coordination environment to allow migratory insertion into an M-C species, a process with a high steric impediment with no previous example on SACs. The studies showcase how SACs can introduce coordination structures that have remained underexplored in catalyst design. These findings offer immense potential for transferring the vast and highly versatile reaction manifold of migratory-insertion-based bond-forming protocols to heterogeneous SACs.
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Affiliation(s)
- Bo Li
- School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Cheng-Wei Ju
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, United States
| | - Wenlong Wang
- School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Yanwei Gu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Shuai Chen
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yongrui Luo
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China
| | - Haozhe Zhang
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, United States
| | - Juan Yang
- School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Hai-Wei Liang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Klaus Müllen
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - William A Goddard
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Yazhou Zhou
- School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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37
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Fernandes GFS, Machado FBC, Ferrão LFA. Electronic Structure of Small Isolated and Supported Manganese Oxide Clusters. J Phys Chem A 2023; 127:8773-8781. [PMID: 37839039 DOI: 10.1021/acs.jpca.3c01644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
In the present work, possible molecular models of the isolated manganese oxides and supported Mn3Ox/Al2O3 structures were built based on small clusters of passivated MnOx. The support was represented as a simplified model of the alumina tetramer cluster based on small fragments of AlOxHy. Combinations of MnOxHy and AlOxHy clusters were made to form both the isolated and supported manganese oxides clusters. The electronic structure of these systems was characterized by ab initio methods (DFT and CASPT2). It was observed that the vertical excitation energy of the isolated and supported Mn3OxHy clusters is significantly lower than that of the alumina cluster model, while both the isolated and supported Mn3OxHy wave function characters are qualitatively similar with respect to the ground state and electronic transition processes, suggesting that the alumina cluster behaves as an inert support, since there is little contribution of this component in the description of the low-lying electronic states. The present study also reports for the first time the spectroscopic parameters of several clusters containing the manganese transition metal atom.
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Affiliation(s)
- Gabriel F S Fernandes
- Departamento de Química, Instituto Tecnológico de Aeronáutica, São José dos Campos,SP 12228-900, Brasil
| | - Francisco B C Machado
- Departamento de Química, Instituto Tecnológico de Aeronáutica, São José dos Campos,SP 12228-900, Brasil
| | - Luiz F A Ferrão
- Departamento de Química, Instituto Tecnológico de Aeronáutica, São José dos Campos,SP 12228-900, Brasil
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38
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Kim SY, Park JW. Approximate Excited-State Geometry Optimization with the State-Averaged Adaptive Sampling Configuration Interaction Algorithm with Large Active Spaces. J Chem Theory Comput 2023; 19:7260-7272. [PMID: 37800852 DOI: 10.1021/acs.jctc.3c00808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
The selected configuration interaction (SCI) wave function is a useful approximation to the full configuration interaction (FCI) one. The adaptive sampling CI (ASCI) method is a deterministic SCI method. By combining ASCI and orbital optimization, the ASCI self-consistent field (ASCI-SCF) method, which is an approximation of the complete active space self-consistent field (CASSCF) method, can be formulated as well. However, their applicability has been tested mainly on the systems in their electronically ground states. In this work, we implement the state-average (SA) ansatz in ASCI-SCF calculations to calculate excited states. We also derive expressions for the approximate analytical gradient and implement them as a computer program. We demonstrate the applicability of the current method for calculating vertical and adiabatic excitation energies and optimizing the molecular geometries of thermally activated delayed fluorescence (TADF) molecules.
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Affiliation(s)
- So Yeon Kim
- Department of Chemistry, Chungbuk National University (CBNU), Cheongju 28644, Korea
| | - Jae Woo Park
- Department of Chemistry, Chungbuk National University (CBNU), Cheongju 28644, Korea
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39
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Helmer J, Hepp A, Berger RJF, Lips F. Synthesis and functionalization of the six-vertex anionic amido-substituted silicon cluster [Si 6{N(SiMe 3)Ph} 5] . Dalton Trans 2023; 52:14949-14955. [PMID: 37800884 DOI: 10.1039/d2dt03952d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
The reaction of the six-vertex amido-substituted silicon cluster Si6{N(SiMe3)Ph}6 1 with two equiv. of KC8 results in the abstraction of K{N(SiMe3)Ph} and leads to the contact ion pair 2 including an anionic silicon cluster with two unsubstituted pyramidal vertices. Facile functionalization of 2 was achieved with MeI, SiCl4 and SiBr4 and results in neutral two-fold functionalized silicon clusters.
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Affiliation(s)
- Joschua Helmer
- Westfälische Wilhelms-Universität Münster, Institut für Anorganische und Analytische Chemie, Corrensstraße 28-30, 48149 Münster, Germany.
| | - Alexander Hepp
- Westfälische Wilhelms-Universität Münster, Institut für Anorganische und Analytische Chemie, Corrensstraße 28-30, 48149 Münster, Germany.
| | - Raphael J F Berger
- Paris Lodron Universität Salzburg, Materialchemie, Jakob-Harringerstr. 2a, 5020 Salzburg, Austria
| | - Felicitas Lips
- Westfälische Wilhelms-Universität Münster, Institut für Anorganische und Analytische Chemie, Corrensstraße 28-30, 48149 Münster, Germany.
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40
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Chao W, Jones GH, Okumura M, Percival CJ, Winiberg FAF. A-Band Absorption Spectrum of the ClSO Radical: Electronic Structure of the Sulfinyl Group. J Phys Chem A 2023; 127:8374-8382. [PMID: 37772907 PMCID: PMC10577680 DOI: 10.1021/acs.jpca.3c04977] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/14/2023] [Indexed: 09/30/2023]
Abstract
Sulfur oxide species (RSOx) play a critical role in many fields, ranging from biology to atmospheric chemistry. Chlorine-containing sulfur oxides may play a key role in sulfate aerosol formation in Venus' cloud layer by catalyzing the oxidation of SO to SO2 via sulfinyl radicals (RSO). We present results from the gas-phase UV-vis transient absorption spectroscopy study of the simplest sulfinyl radical, ClSO, generated from the pulsed-laser photolysis of thionyl chloride at 248 nm (at 40 Torr of N2 and 292 K). A weak absorption spectrum from 350 to 480 nm with a peak at 385 nm was observed, with partially resolved vibronic bands (spacing = 226 cm-1), and a peak cross section σ(385 nm) = (7.6 ± 1.9) × 10-20 cm2. From ab initio calculations at the EOMEE-CCSD/ano-pVQZ level, we assigned this band to 12A' ← X2A″ and 22A' ← X2A″ transitions. The spectrum was modeled as a sum of a bound-to-free transition to the 12A' state and a bound-to-bound transition to the 22A' state with similar oscillator strengths; the prediction agreed well with the observed spectrum. We attributed the vibronic structure to a progression in the bending vibration of the 22A' state. Further calculations at the XDW-CASPT2 level predicted a conical intersection between the excited 12A' and 22A' potential energy surfaces near the Franck-Condon region. The geometry of the minimum-energy conical intersection was similar to that of the ground-state geometry. The lack of structure at shorter wavelengths could be evidence of a short excited-state lifetime arising from strong vibronic coupling. From simplified molecular orbital analysis, we attributed the ClSO spectrum to transitions involving the out-of-plane π/π* orbitals along the S-O bond and the in-plane orbital possessing a σ/σ* character along the S-Cl bond. We hypothesize that these orbitals are common to other sulfinyl radicals, RSO, which would share a combination of a strong and a weak transition in the UV (near 300 nm) and visible (400-600 nm) regions.
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Affiliation(s)
- Wen Chao
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, 1200 E California Blvd, Pasadena, California 91125, United States
| | - Gregory H. Jones
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, 1200 E California Blvd, Pasadena, California 91125, United States
| | - Mitchio Okumura
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, 1200 E California Blvd, Pasadena, California 91125, United States
| | - Carl J. Percival
- Jet
Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, United States
| | - Frank A. F. Winiberg
- Jet
Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, United States
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41
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Leach IF, Speelman T, Somsen C, Klein JEMN, Havenith RWA. Revisiting sp 2 Dilithio Methandiides: From Geometric Curiosity to Simple Bonding Description. Chemistry 2023; 29:e202301911. [PMID: 37427720 DOI: 10.1002/chem.202301911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 07/11/2023]
Abstract
The reported tetracoordinate dilithio methandiide complex from Liddle and co-workers (1) is investigated from a coordination chemistry perspective, to probe the origin of its intriguing geometry. Through the application of a variety of computational techniques, non-covalent (steric, electrostatic) interactions are found to be dominant. Further, we arrive at a bonding description which emphasizes the tricoordinate sp2 -hybridized nature of the central methandiide carbon, differing somewhat from the original proposal. Thus, 1 is distinct from other dilithio methandiides since it contains only one C-Li σ-bond, and is found to be comparable to a simple aryllithium compound, phenyllithium.
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Affiliation(s)
- Isaac F Leach
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Tom Speelman
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Chiel Somsen
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Johannes E M N Klein
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Remco W A Havenith
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Ghent Quantum Chemistry Group, Department of Chemistry, Ghent University, 9000, Gent, Belgium
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42
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Barchenko M, Malcomson T, de Visser SP, O’Malley PJ. Computational Study on the Influence of Mo/V Centers on the Electronic Structure and Hydrazine Reduction Capability of [MFe 3S 4] 3+/2+ Complexes. Inorg Chem 2023; 62:16401-16411. [PMID: 37756478 PMCID: PMC10565805 DOI: 10.1021/acs.inorgchem.3c02072] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Indexed: 09/29/2023]
Abstract
[MFe3S4] cubanes have for some time been of interest for their ability to mimic the electronic and geometric structure of the active site of nitrogenase, the enzyme responsible for fixing N2 to NH3. Nitrogenase naturally occurs in three forms, with the major difference being that the metal ion present in the cofactor active site is either molybdenum (FeMoco), vanadium (FeVco), or iron. The molybdenum and vanadium versions of these cofactors are more closely studied, owing to their larger abundance and rate of catalysis. In this study, we compare free energy profiles and electronic properties of the Mo/V cubanes at various stages during the reduction of N2H4 to NH3. Our findings highlight the differences in how the complexes facilitate the reaction, in particular, vanadium's comparatively weaker ability to interact with the Fe/S network and stabilize reducing electrons prior to N-N bond cleavage, which may have implications when considering the lower efficiency of the vanadium-dependent nitrogenase.
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Affiliation(s)
- Maxim Barchenko
- Department
of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K.
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess
Street, Manchester M1 7DN, U.K.
| | - Thomas Malcomson
- Department
of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K.
| | - Sam P. de Visser
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess
Street, Manchester M1 7DN, U.K.
- Department
of Chemical Engineering, The University
of Manchester, Oxford
Road, Manchester M13 9PL, U.K.
| | - Patrick J. O’Malley
- Department
of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K.
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43
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Faizan M, Kumar A, Raghasudha M, Pawar R. PIO and IBO analysis to unravel the hidden details of the CO 2 sequestration mechanism of aromatically tempered N/B-based IFLPs. Phys Chem Chem Phys 2023; 25:24809-24818. [PMID: 37671753 DOI: 10.1039/d3cp02928j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Enhancing the catalytic reactivity of Frustrated Lewis Pairs (FLPs) in various activities such as CO2 activation and sequestration has recently gained interest among researchers around the globe. A recent investigation showed the use of aromaticity as a tool to modulate the catalytic behaviour of FLPs, establishing a whole new dimension in this area. In this work, aromatically tempered N/B-based intramolecular frustrated Lewis Pairs (IFLPs) are proposed for CO2 sequestration. Density functional theory (DFT)-based calculations were carried out to probe the reaction mechanism. The detailed mechanistic investigation was carried out using intrinsic reaction coordinate (IRC), principal interacting orbital (PIO), intrinsic bond orbital (IBO) and natural bonding orbital (NBO) analyses. The results show that aromatic gain in the system at the basic sites lowers the activation barrier, whereas the antiaromatic gain results in increased activation energy. The sequestration mechanism was found to be an asynchronous concerted mechanism, and polar solvents result in higher asynchronicity. This work, for the first time, reports asynchronicity in the catalytic behavior of aromatically tempered IFLPs, which can be crucial to designing better IFLPs for CO2 sequestration.
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Affiliation(s)
- Mohmmad Faizan
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana-506004, India.
| | - Adarsh Kumar
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana-506004, India.
| | - Mucherla Raghasudha
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana-506004, India.
| | - Ravinder Pawar
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana-506004, India.
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44
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Faizan M, Saini K, Mucherla R, Pawar R. Unprecedented Activation of CO 2 by α-Amino Boronic Acids. J Phys Chem A 2023; 127:7429-7442. [PMID: 37656936 DOI: 10.1021/acs.jpca.3c02508] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/03/2023]
Abstract
Efficient and environmentally benign transformation of carbon dioxide (CO2) into valuable chemicals is mainly obstructed by the lack of suitable catalysts. To date, various catalysts have already been investigated for the conversion of CO2 molecules, but still finding metal-free, simple, and environment-friendly catalysts is a topic of utmost interest among researchers. Thus, in this regard, the present work projects α-amino boronic acids (AABs) as a metal-free and simple catalyst for CO2 activation. The density functional theory (DFT)-based calculations have been carried out to explore the catalytic potential of AABs. The detailed electronic structure analysis of the considered AABs unveils the catalytic similarities with frustrated Lewis pairs (FLPs) in a gas phase. Interestingly, a peculiar catalytic action of AABs has been observed in the presence of solvents. The contrasting catalytic behavior of AABs in solvents has been extensively investigated by employing principal interacting orbital (PIO), intrinsic bond orbital (IBO), and natural bond orbital (NBO) analyses along the reaction paths. The results of the orbital studies provide concrete ground for the observed reaction mechanism. Further, the energetic analysis of the reaction of CO2 with AABs reveals that <5 kcal/mol energy is required for activation in a solvent phase, and the formed adducts are readily active. These observations show that AABs can be considered as an efficient catalyst for CO2 activation.
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Affiliation(s)
- Mohmmad Faizan
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal 506004, Telangana, India
| | - Kajal Saini
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal 506004, Telangana, India
| | - Raghasudha Mucherla
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal 506004, Telangana, India
| | - Ravinder Pawar
- Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal 506004, Telangana, India
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45
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Barchenko M, O’Malley PJ, de Visser SP. Mechanism of Nitrogen Reduction to Ammonia in a Diiron Model of Nitrogenase. Inorg Chem 2023; 62:14715-14726. [PMID: 37650683 PMCID: PMC10498488 DOI: 10.1021/acs.inorgchem.3c02089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Indexed: 09/01/2023]
Abstract
Nitrogenase is a fascinating enzyme in biology that reduces dinitrogen from air to ammonia through stepwise reduction and protonation. Despite it being studied in detail by experimental and computational groups, there are still many unknown factors in the catalytic cycle of nitrogenase, especially related to the addition of protons and electrons and their order. A recent biomimetic study characterized a potential dinitrogen-bridged diiron cluster as a synthetic model of nitrogenase. Using strong acid and reductants, the dinitrogen was converted into ammonia molecules, but details of the mechanism remains unknown. In particular, it was unclear from the experimental studies whether the proton and electron transfer steps are sequential or alternating. Moreover, the work failed to establish what the function of the diiron core is and whether it split into mononuclear iron fragments during the reaction. To understand the structure and reactivity of the biomimetic dinitrogen-bridged diiron complex [(P2P'PhFeH)2(μ-N2)] with triphenylphosphine ligands, we performed a density functional theory study. Our computational methods were validated against experimental crystal structure coordinates, Mössbauer parameters, and vibrational frequencies and show excellent agreement. Subsequently, we investigated the alternating and consecutive addition of electrons and protons to the system. The calculations identify a number of possible reaction channels, namely, same-site protonation, alternating protonation, and complex dissociation into mononuclear iron centers. The calculations show that the overall mechanism is not a pure sequential set of electron and proton transfers but a mixture of alternating and consecutive steps. In particular, the first reaction steps will start with double proton transfer followed by an electron transfer, while thereafter, there is another proton transfer and a second electron transfer to give a complex whereby ammonia can split off with a low energetic barrier. The second channel starts with alternating protonation of the two nitrogen atoms, whereafter the initial double proton transfer, electrons and protons are added sequentially to form a hydrazine-bound complex. The latter split off ammonia spontaneously after further protonation. The various reaction channels are analyzed with valence bond and orbital diagrams. We anticipate the nitrogenase enzyme to operate with mixed alternating and consecutive protonation and electron transfer steps.
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Affiliation(s)
- Maxim Barchenko
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Patrick J. O’Malley
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Sam P. de Visser
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
- Department
of Chemical Engineering, The University
of Manchester, Oxford
Road, Manchester M13 9PL, U.K.
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46
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Möbs M, Graubner T, Karttunen AJ, Kraus F. [(μ 3 -F)(BrF 5 ) 3 ] - - An Unprecedented Molecular Fluoridobromate(V) Anion in Cs[Br 3 F 16 ]. Chemistry 2023; 29:e202301876. [PMID: 37522612 DOI: 10.1002/chem.202301876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Indexed: 08/01/2023]
Abstract
The reaction of Cs[BrF6 ] with BrF5 gave the compound Cs[Br3 F16 ] with the unprecedented propeller-shaped, C3 -symmetric [(μ3 -F)(BrF5 )3 ]- anion. All other currently known fluoridobromates(V) contain only octahedral [BrF6 ]- anions, which, unlike the related [IF6 ]- anions, never exhibited stereochemical activity of the lone pair on the Br atoms. Despite the same coordination number of six for the Br atom in the [BrF6 ]- and [(μ3 -F)(BrF5 )3 ]- anions, the longer μ3 -F-Br bonds provide additional space, allowing the lone pairs on the Br atoms to become stereochemically active. Cs[Br3 F16 ] was characterized by single-crystal X-ray diffraction, Raman spectroscopy, and quantum-chemical calculations for both the solid-state compound and the isolated anion at 0 K. Intrinsic bond orbital calculations show that the μ3 -F-Br bond is essentially ionic in nature and also underpin the stereochemical activity of the lone pairs of the Br(V) atoms.
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Affiliation(s)
- Martin Möbs
- Anorganische Chemie, Fluorchemie, Philipps-Universität Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany
| | - Tim Graubner
- Anorganische Chemie, Fluorchemie, Philipps-Universität Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany
| | - Antti J Karttunen
- Department of Chemistry and Materials Science, Aalto University, 00076, Espoo, Finland
| | - Florian Kraus
- Anorganische Chemie, Fluorchemie, Philipps-Universität Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany
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47
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Schulz J, Antala J, Rezazgui D, Císařová I, Štěpnička P. Synthesis, Structure, Reactivity, and Intramolecular Donor-Acceptor Interactions in a Phosphinoferrocene Stibine and Its Corresponding Phosphine Chalcogenides and Stiboranes. Inorg Chem 2023; 62:14028-14043. [PMID: 37566394 PMCID: PMC10466383 DOI: 10.1021/acs.inorgchem.3c02075] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Indexed: 08/12/2023]
Abstract
Ferrocene-based phosphines equipped with additional functional groups are versatile ligands for coordination chemistry and catalysis. This contribution describes a new compound of this type, combining phosphine and stibine groups at the ferrocene backbone, viz. 1-(diphenylphosphino)-1'-(diphenylstibino)ferrocene (1). Phosphinostibine 1 and the corresponding P-chalcogenide derivatives Ph2P(E)fcSbPh2 (1E, fc = ferrocene-1,1'-diyl, E = O, S, Se) were synthesized and further converted to the corresponding stiboranes Ph2P(E)fcSb(O2C6Cl4)Ph2 (6 and 6E) by oxidation with o-chloranil. All compounds were characterized by spectroscopic methods, X-ray diffraction analysis, cyclic voltammetry, and theoretical methods. Both NMR spectroscopy and DFT calculations confirmed the presence of P → Sb and P═O → Sb donor-acceptor interactions in 6 and 6O, triggered by the oxidation of the stibine moiety into Lewis acidic stiborane. The corresponding interactions in 6S and 6Se were of the same type but significantly weaker. A coordination study with AuCl as the model metal fragment revealed that the phosphine group acts as the "primary" coordination site, in line with its higher basicity. The obtained Au(I) complexes were applied as catalysts in the Au-catalyzed cyclization of N-propargylbenzamide and in the oxidative [2 + 2 + 1] cyclization of ethynylbenzene with acetonitrile and pyridine N-oxides. The catalytic results showed that the stibine complexes had worse catalytic performance than their phosphine counterparts, most likely due to the formation of weaker coordination bonds and hence poorer stabilization of the active metal species. Nevertheless, the stibine moiety could be used to fine-tune the properties of the ligated metal center by changing the oxidation state or substituents at the "remote" Sb atom.
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Affiliation(s)
- Jiří Schulz
- Department
of Inorganic Chemistry,
Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic
| | - Jakub Antala
- Department
of Inorganic Chemistry,
Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic
| | - David Rezazgui
- Department
of Inorganic Chemistry,
Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic
| | - Ivana Císařová
- Department
of Inorganic Chemistry,
Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic
| | - Petr Štěpnička
- Department
of Inorganic Chemistry,
Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic
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48
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Kametani Y, Ikeda K, Yoshizawa K, Shiota Y. Mechanistic Study of Reduction of Nitrite to NO by the Copper(II) Complex: Different Concerted Proton-Electron Transfer Reactivity between Nitrite and Nitro Complexes. Inorg Chem 2023; 62:13765-13774. [PMID: 37590095 DOI: 10.1021/acs.inorgchem.3c01383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
The literature contains numerous reports of copper complexes for nitrite (NO2-) reduction. However, details of how protons and electrons arrive and how nitric oxide (NO) is released remain unknown. The influence of the coordination mode of nitrite on reactivity is also under debate. Kundu and co-workers have reported nitrite reduction by a copper(II) complex [J. Am. Chem. Soc. 2020, 142, 1726-1730]. In their report, the copper(II) complex reduced nitrite using a phenol derivative as a reductant, resulting in NO, a hydroxyl copper(II) complex, and the corresponding biphenol. Also, the involvement of proton-coupled electron transfer was proposed by mechanistic studies. Herein, density functional theory calculations were performed to determine a mechanism for reduction of nitrite by a copper(II) complex. As a result of geometry optimization of an initial complex, two possible structures were obtained: Cu-ONO and Cu-NO2. Two possible reaction pathways initiated from Cu-ONO or Cu-NO2 were then considered. The calculation results indicated that the Cu-ONO pathway is energetically favorable. When changes in the electronic structure were considered, both pathways were found to involve concerted proton-electron transfer (CPET). In addition, an intrinsic reaction coordinate analysis revealed that the two pathways were achieved by different types of CPET. Furthermore, an intrinsic bond orbital analysis clearly indicated that, in the Cu-ONO pathway, the chemical events involved proceeded concertedly yet asynchronously.
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Affiliation(s)
- Yohei Kametani
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kei Ikeda
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yoshihito Shiota
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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Huchthausen J, Escher BI, Grasse N, König M, Beil S, Henneberger L. Reactivity of Acrylamides Causes Cytotoxicity and Activates Oxidative Stress Response. Chem Res Toxicol 2023; 36:1374-1385. [PMID: 37531411 PMCID: PMC10445285 DOI: 10.1021/acs.chemrestox.3c00115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Indexed: 08/04/2023]
Abstract
Acrylamides are widely used industrial chemicals that cause adverse effects in humans or animals, such as carcinogenicity or neurotoxicity. The excess toxicity of these reactive electrophilic chemicals is especially interesting, as it is mostly triggered by covalent reactions with biological nucleophiles, such as DNA bases, proteins, or peptides. The cytotoxicity and activation of oxidative stress response of 10 (meth)acrylamides measured in three reporter gene cell lines occurred at similar concentrations. Most acrylamides exhibited high excess toxicity, while methacrylamides acted as baseline toxicants. The (meth)acrylamides showed no reactivity toward the hard biological nucleophile 2-deoxyguanosine (2DG) within 24 h, and only acrylamides reacted with the soft nucleophile glutathione (GSH). Second-order degradation rate constants (kGSH) were measured for all acrylamides with N,N'-methylenebis(acrylamide) (NMBA) showing the highest kGSH (134.800 M-1 h-1) and N,N-diethylacrylamide (NDA) the lowest kGSH (2.574 M-1 h-1). Liquid chromatography coupled to high-resolution mass spectrometry was used to confirm the GSH conjugates of the acrylamides with a double conjugate formed for NMBA. The differences in reactivity between acrylamides and methacrylamides could be explained by the charge density of the carbon atoms because the electron-donating inductive effect of the methyl group of the methacrylamides lowered their electrophilicity and thus their reactivity. The differences in reactivity within the group of acrylamides could be explained by the energy of the lowest unoccupied molecular orbital and steric hindrance. Cytotoxicity and activation of oxidative stress response were linearly correlated with the second-order reaction rate constants of the acrylamides with GSH. The reaction of the acrylamides with GSH is hence not only a detoxification mechanism but also leads to disturbances of the redox balance, making the cells more vulnerable to reactive oxygen species. The reactivity of acrylamides explained the oxidative stress response and cytotoxicity in the cells, and the lack of reactivity of the methacrylamides led to baseline toxicity.
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Affiliation(s)
- Julia Huchthausen
- Department
of Cell Toxicology, Helmholtz Centre for
Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
| | - Beate I. Escher
- Department
of Cell Toxicology, Helmholtz Centre for
Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
- Department
of Geosciences, Eberhard Karls University
Tübingen, Environmental Toxicology, 72076 Tübingen, Germany
| | - Nico Grasse
- Department
of Analytical Chemistry, Helmholtz Centre
for Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
| | - Maria König
- Department
of Cell Toxicology, Helmholtz Centre for
Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
| | - Stephan Beil
- Institute
of Water Chemistry, Technische Universität
Dresden, 01069 Dresden, Germany
| | - Luise Henneberger
- Department
of Cell Toxicology, Helmholtz Centre for
Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
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50
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Zhang V, Accardo JV, Kevlishvili I, Woods EF, Chapman SJ, Eckdahl CT, Stern CL, Kulik HJ, Kalow JA. Tailoring Dynamic Hydrogels by Controlling Associative Exchange Rates. Chem 2023; 9:2298-3317. [PMID: 37790656 PMCID: PMC10545375 DOI: 10.1016/j.chempr.2023.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Dithioalkylidenes are a newly-developed class of conjugate acceptors that undergo thiol exchange via an associative mechanism, enabling decoupling of key material properties for sustainability, biomedical, and sensing applications. Here, we show that the exchange rate is highly sensitive to the structure of the acceptor and tunable over four orders of magnitude in aqueous environments. Cyclic acceptors exchange rapidly, from 0.95 to 15.6 M-1s-1, while acyclic acceptors exchange between 3.77x10-3 and 2.17x10-2 M-1s-1. Computational, spectroscopic, and structural data suggest that cyclic acceptors are more reactive than their acyclic counterparts because of resonance stabilization of the tetrahedral exchange intermediate. We parametrize molecular reactivity with respect to computed descriptors of the electrophilic site and leverage this insight to design a compound with intermediate characteristics. Lastly, we incorporate this dynamic bond into hydrogels and demonstrate that the characteristic stress relaxation time (τ) is directly proportional to molecular kex.
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Affiliation(s)
- Vivian Zhang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA
| | - Joseph. V Accardo
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA
| | - Ilia Kevlishvili
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames Street, Cambridge, MA, USA
| | - Eliot F. Woods
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA
| | - Steven J. Chapman
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA
| | | | - Charlotte L. Stern
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA
| | - Heather J. Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames Street, Cambridge, MA, USA
| | - Julia A. Kalow
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA
- Lead contact
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