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Guan Y, Chang K, Su Y, Xu X, Xu X. Frustrated Lewis Pair-Type Reactivity of Intermolecular Rare-Earth Aryloxide and N-Heterocyclic Carbene/Olefin Combinations. Chem Asian J 2024:e202400190. [PMID: 38451014 DOI: 10.1002/asia.202400190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 03/08/2024]
Abstract
This work reports the cooperative reactivity of rare-earth aryloxide complexes with N-heterocyclic carbene (NHC) or N-heterocyclic olefin (NHO), showcasing their synergistic effect on the activation of H2 and diverse organic substrates. Reactions of RE(OAr)3 (RE=La, Sm, and Y; Ar=2,6-tBu2-C6H3) with unsaturated NHC ItBu (:C[N(R)CH]2, R=tBu) isolated abnormally bound RE metal NHC complexes RE/aNHC. In contrast, no metal-NHO adducts were formed when RE(OAr)3 were treated with NHO (R2C=C[N(R)C(R)]2, R=CH3). Both RE/aNHC and RE/NHO Lewis pairs enabled cooperative H2 activation. Furthermore, RE(OAr)3 were found to catalyze the hydrogenation of the exocyclic C=C double bond of NHO under mild conditions. Moreover, treatment of the La/aNHC complex with benzaldehyde produced a La/C4 1,2-addition product. The La/NHO Lewis pair could react with (trimethylsilyl)diazomethane and α, β-conjugated imine, affording an isocyanotrimethylsilyl lanthanum amide complex and a La/C 1,4-addition product, respectively.
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Affiliation(s)
- Yiwen Guan
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123, Suzhou, P. R. China
| | - Kejian Chang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123, Suzhou, P. R. China
| | - Yujie Su
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123, Suzhou, P. R. China
| | - Xian Xu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123, Suzhou, P. R. China
| | - Xin Xu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123, Suzhou, P. R. China
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2
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Emanuelson C, Bardhan A, Deiters A. DNA Logic Gates for Small Molecule Activation Circuits in Cells. ACS Synth Biol 2024; 13:538-545. [PMID: 38306634 PMCID: PMC10877608 DOI: 10.1021/acssynbio.3c00474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 01/09/2024] [Accepted: 01/09/2024] [Indexed: 02/04/2024]
Abstract
DNA-based devices such as DNA logic gates self-assemble into supramolecular structures, as dictated by the sequences of the constituent oligonucleotides and their predictable Watson-Crick base pairing interactions. The programmable nature of DNA-based devices permits the design and implementation of DNA circuits that interact in a dynamic and sequential manner capable of spatially arranging disparate DNA species. Here, we report the application of an activatable fluorescence reporter based on a proximity-driven inverse electron demand Diels-Alder (IEDDA) reaction and its robust integration with DNA strand displacement circuits. In response to specific DNA input patterns, sequential strand displacement reactions are initiated and culminate in the hybridization of two modified DNA strands carrying probes capable of undergoing an IEDDA reaction between a vinyl-ether-caged fluorophore and its reactive partner tetrazine, leading to the activation of fluorescence. This approach provides a major advantage for DNA computing in mammalian cells since circuit degradation does not induce fluorescence, in contrast to traditional fluorophore-quencher designs. We demonstrate the robustness and sensitivity of the reporter by testing its ability to serve as a readout for DNA logic circuits of varying complexity inside cells.
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Affiliation(s)
- Cole Emanuelson
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Anirban Bardhan
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Alexander Deiters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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3
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Nath S, Yadav E, Raghuvanshi A, Singh AK. Ru(II) Complexes with Protic- and Anionic-Naked-NHC Ligands for Cooperative Activation of Small Molecules. Chemistry 2023; 29:e202301971. [PMID: 37377294 DOI: 10.1002/chem.202301971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 06/29/2023]
Abstract
A set of ruthenium(II)-protic-N-heterocyclic carbene complexes, [Ru(NNCH )(PPh3 )2 (X)]Cl (1, X=Cl and 2, X=H) and their deprotonated forms [Ru(NNC)(PPh3 )2 (X)] (1', X=Cl and 2', X=H), in which NNC is a new unsymmetrical pincer ligand, are reported. The four complexes are interconvertible by simple acid-base chemistry. The combined theoretical and spectroscopic investigations indicate charge segregation in anionic-NHC complexes (1' and 2') and can be described from a Lewis pair perspective. The chemical reactivity of deprotonated complex 1' shows cooperative small molecule activation. Complex 1' activates H-H bond of hydrogen, C(sp3 )-I bond of iodomethane, and C(sp)-H bond of phenylacetylene. The activation of CO2 using anionic NHC complex 1' at moderate temperature and ambient pressure and subsequent conversion to formate is also described. All the new compounds have been characterized using ESI-MS, 1 H, 13 C, and 31 P NMR spectroscopy. Molecular structures of 1, 2, and 2' have also been determined with single-crystal X-ray diffraction. The cooperative small molecule activation perspective broadens the scope of potential applications of anionic-NHC complexes in small molecule activation, including the conversion of carbon dioxide to formate, a much sought after reaction in the renewable energy and sustainable development domains.
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Affiliation(s)
- Shambhu Nath
- Department of Chemistry, Indian Institute of Technology Indore, Simrol, Indore, 453552, India
| | - Ekta Yadav
- Department of Chemistry, Indian Institute of Technology Indore, Simrol, Indore, 453552, India
| | - Abhinav Raghuvanshi
- Department of Chemistry, Indian Institute of Technology Indore, Simrol, Indore, 453552, India
| | - Amrendra K Singh
- Department of Chemistry, Indian Institute of Technology Indore, Simrol, Indore, 453552, India
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King AJ, Abbenseth J, Goicoechea JM. Reactivity of a Strictly T-Shaped Phosphine Ligated by an Acridane Derived NNN Pincer Ligand. Chemistry 2023; 29:e202300818. [PMID: 37042718 PMCID: PMC10947599 DOI: 10.1002/chem.202300818] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/10/2023] [Accepted: 04/12/2023] [Indexed: 04/13/2023]
Abstract
The steric tuning of a tridentate acridane-derived NNN pincer ligand allows for the isolation of a strictly T-shaped phosphine that exhibits ambiphilic reactivity. Well-defined phosphorus-centered reactivity towards nucleophiles and electrophiles is reported, contrasting with prior reports on this class of compounds. Reactions towards oxidants are also described. The latter result in the two-electron oxidation of the phosphorus atom from +III to +V and are accompanied by a strong geometric distortion of the NNN pincer ligand. By contrast, cooperative activation of E-H (HCl, HBcat, HOMe) bonds proceeds with retention of the phosphorus redox state. When using H2 O as a substrate, the reaction results in the full disassembly of H2 O to its constituent atoms, highlighting the potential of this platform for small molecule activation reactions.
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Affiliation(s)
- Aaron J. King
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK
| | - Josh Abbenseth
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Straße 212489BerlinGermany
| | - Jose M. Goicoechea
- Department of ChemistryIndiana University800 E. Kirkland Ave.Bloomington, In47401USA
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Yang L, Qu Y, Wang J, Xu W, Zhao Y, Yang XJ. Diverse Reactions of α-Diimine-Ligated Mg(I)-Mg(I)-Bonded Compound with Carbodiimides. Chemistry 2023:e202301266. [PMID: 37226708 DOI: 10.1002/chem.202301266] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/20/2023] [Accepted: 05/22/2023] [Indexed: 05/26/2023]
Abstract
The α-diimine-ligated dimagnesium(I) compound [K(thf)3]2[LMg-MgL] (1, L = [(2,6-iPr2C6H3)NC(Me)]22-) displays diverse reactivities toward carbodiimides (RN=C=NR) with different R substituents. In the reaction of 1 with Me3SiNCNSiMe3, one of the easily leaving trimethylsilyl groups loses to yield the Me3SiNCN- moiety that either bridges two Mg(II) centers (2) or terminally coordinated (3). In contrast, with the similarly bulky tBuNCNtBu, the carbodiimide inserts into Mg-Mg bond with accompanying C-H activation of a ligand or solvent (products 4 and 5). In the case of dicyclohexyl or diisopropyl carbodiimide, reductive C-C coupling of two RNCNR molecules occurs to form the [C2(NR)4]2- diamido moiety that bridges two Mg centers, giving complexes [{K(dme)2}2LMg(μ-{C2(NR)4})MgL] (6, R = Cy; 7, R = iPr) and [L•-Mg(μ-{C2(NR)4})MgL•-] (8). Most interestingly, by reaction of 1 with Me3SiC≡CSiMe3, the acetylide complex [K(dme)][LMg(C≡CSiMe3)(dme)] (9) was prepared, which undergoes a rare "double insertion" with CyNCNCy to afford [K(solv)][K(dme)2LMg(NCy)2C-C≡C-C(NCy)2MgL] (10) containing a diacetylide-coupled bis(amidinate) ligand that bridges two Mg atoms.
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Affiliation(s)
- Li Yang
- Northwest University, College of Chemistry and Materials Science, CHINA
| | - Yao Qu
- Beijing Institute of Technology, School of Chemistry and Chemical Engineering, CHINA
| | - Juju Wang
- Northwest University, College of Chemistry and Materials Science, CHINA
| | - Wenhua Xu
- Northwest University, College of Chemistry and Materials Science, CHINA
| | - Yanxia Zhao
- Northwest University, College of Chemistry and Materials Science, CHINA
| | - Xiao-Juan Yang
- Beijing Institute of Technology, School of Chemistry and Chemical Engineering, East Liangxiang Road 8, 10081, Beijing, CHINA
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Eisner T, Kostenko A, Hanusch F, Inoue S. Room-Temperature-Observable Interconversion Between Si(IV) and Si(II) via Reversible Intramolecular Insertion Into an Aromatic C-C Bond. Chemistry 2022; 28:e202202330. [PMID: 36098491 PMCID: PMC10092829 DOI: 10.1002/chem.202202330] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Indexed: 12/14/2022]
Abstract
An easily isolable silacycloheptatriene (silepin) 1 b was synthesized from the reaction of a N-heterocyclic imino (IPrN) substituted tribromosilane IPrNSiBr3 with the sterically congested bis(trimethylsilyl)triisopropylsilyl silanide KSi(TMS)2 Si(i Pr)3 (BTTPS). In solution, the Si(IV) silepin 1 b is in a thermodynamic equilibrium with the acyclic Si(II) silylene 1 a. The relative concentration of the Si(II) or Si(IV) isomers can be controlled by temperature variation and observed by variable temperature NMR and UV/Vis spectroscopy. DFT calculations show a small reaction barrier for the Si(II)⇌Si(IV) interconversion and a small energy gap between the Si(II) and Si(IV) species. The reactivity of 1 a/b is demonstrated on a variety of small molecules.
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Affiliation(s)
- Teresa Eisner
- School of Natural Sciences, Department of Chemistry WACKER-Institute of Silicon Chemistry and Catalysis Research Centre Technical University of Munich, Lichtenbergstraße 4, 85748, Garching bei München, Germany
| | - Arseni Kostenko
- School of Natural Sciences, Department of Chemistry WACKER-Institute of Silicon Chemistry and Catalysis Research Centre Technical University of Munich, Lichtenbergstraße 4, 85748, Garching bei München, Germany
| | - Franziska Hanusch
- School of Natural Sciences, Department of Chemistry WACKER-Institute of Silicon Chemistry and Catalysis Research Centre Technical University of Munich, Lichtenbergstraße 4, 85748, Garching bei München, Germany
| | - Shigeyoshi Inoue
- School of Natural Sciences, Department of Chemistry WACKER-Institute of Silicon Chemistry and Catalysis Research Centre Technical University of Munich, Lichtenbergstraße 4, 85748, Garching bei München, Germany
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Bedbur K, Stucke N, Liehrs L, Krahmer J, Tuczek F. Catalytic Ammonia Synthesis Mediated by Molybdenum Complexes with PN 3P Pincer Ligands: Influence of P/N Substituents and Molecular Mechanism. Molecules 2022; 27:molecules27227843. [PMID: 36431964 PMCID: PMC9692791 DOI: 10.3390/molecules27227843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/08/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022]
Abstract
Three molybdenum trihalogenido complexes supported by different PN3P pincer ligands were synthesized and investigated regarding their activity towards catalytic N2-to-NH3 conversion. The highest yields were obtained with the H-PN3PtBu ligand. The corresponding Mo(V)-nitrido complex also shows good catalytic activity. Experiments regarding the formation of the analogous Mo(IV)-nitrido complex lead to the conclusion that the mechanism of catalytic ammonia formation mediated by the title systems does not involve N-N cleavage of a dinuclear Mo-dinitrogen complex, but follows the classic Chatt cycle.
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8
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Zovko C, Krätschmer F, Schmidt S, Seifert TP, Gamer MT, Roesky PW. A Phosphine-ß-diketiminate Nickel(I)-Complex for Small Molecule Activation. Chempluschem 2022; 87:e202200288. [PMID: 36514880 DOI: 10.1002/cplu.202200288] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 11/07/2022] [Indexed: 11/10/2022]
Abstract
A bis(diphenyl)-phosphine functionalized ß-diketimine ligand (PNac-H) was applied for the synthesis of a subvalent Ni(I) complex [PNac-Ni]. Here, the Ni(I) center is stabilized by a tetradentate PNNP-type pocket, forming a square planar coordination sphere. Subsequently, the Ni(I) complex was investigated with regard to its reactivity and the activation of small molecules. The reductive potential of Ni(I) enabled an activation of different substrate classes, such as CH2 X2 (X=Br, I), I2 or Ph2 E2 (E=S, Se). The ligand's design allows a stabilization of the reactive Ni(I) species while at the same time enabling activation processes due to a hemilabile coordination behavior and accessible axial coordination sites. The activation products have been characterized by single crystal X-ray diffraction, NMR and IR spectroscopy as well as elemental analysis.
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Affiliation(s)
- Christina Zovko
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Frederic Krätschmer
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Sarah Schmidt
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Tim P Seifert
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Michael T Gamer
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Peter W Roesky
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
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Sun X, Hinz A, Kucher H, Gamer MT, Roesky PW. Stereoselective Activation of Small Molecules by a Stable Chiral Silene. Chemistry 2022; 28:e202201963. [PMID: 35762907 DOI: 10.1002/chem.202201963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Indexed: 01/07/2023]
Abstract
The reaction of the dilithium salt of the enantiopure (S)-BINOL (1,1'-bi-2-naphthol) with two equivalents of the amidinate-stabilized chlorosilylene [LPh SiCl] (LPh =PhC(NtBu)2 ) led to the formation of the first example of a chiral cyclic silene species comprising an (S)-BINOL ligand. The reactivity of the Si=C bond was investigated by reaction with elemental sulfur, CO2 and HCl. The reaction with S8 led to a Si=C bond cleavage and concomitantly to a ring-opened product with imine and silanethione functional groups. The reaction with CO2 resulted in the cleavage of the CO2 molecule into a carbonyl group and an isolated O atom, while a new stereocenter is formed in a highly selective manner. According to DFT calculations, the [2+2] cycloaddition product is the key intermediate. Further reactivity studies of the chiral cyclic silene with HCl resulted in a stereoselective addition to the Si=C bond, while the fully selective formation of two stereocenters was achieved. The quantitative stereoselective addition of CO2 and HCl to a Si=C bond is unprecedented.
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Affiliation(s)
- Xiaofei Sun
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Alexander Hinz
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Hannes Kucher
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Michael T Gamer
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Peter W Roesky
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany
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Paula S, Goulding LS, Robertson KN, Clyburne JAC. Simple Ion-Gas Mixtures as a Source of Key Molecules Relevant to Prebiotic Chemistry. Molecules 2021; 26:7394. [PMID: 34885977 DOI: 10.3390/molecules26237394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/15/2021] [Accepted: 11/30/2021] [Indexed: 11/17/2022] Open
Abstract
Very simple chemistry can result in the rapid and high-yield production of key prebiotic inorganic molecules. The two reactions investigated here involve such simple systems, (a) carbon disulfide (CS2) and acetate (CH3COO¯) and (b) sulfur dioxide (SO2) and formate (HCOO¯). They have been carried out under non-aqueous conditions, either in an organic solvent or with a powdered salt exposed to the requisite gas. Under such dry conditions the first reaction generated the thioacetate anion [CH3COS]¯ while the second produced the radical [SO2·]¯anion. Anhydrous conditions are not rare and may have arisen on the early earth at sites where an interface between different phases (liquid/gas or solid/gas) could be generated. This is one way to rationalize the formation of molecules and ions (such as we have produced) necessary in the prebiotic world. Interpretation of our results provides insight into scenarios consistent with the more prominent theories of abiogenesis.
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Abbenseth J, Townrow OPE, Goicoechea JM. Thermoneutral N-H Bond Activation of Ammonia by a Geometrically Constrained Phosphine. Angew Chem Int Ed Engl 2021; 60:23625-23629. [PMID: 34478227 PMCID: PMC8596738 DOI: 10.1002/anie.202111017] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Indexed: 01/07/2023]
Abstract
A geometrically constrained phosphine bearing a tridentate NNS pincer ligand is reported. The effect of the geometric constraint on the electronic structure was probed by theoretical calculations and derivatization reactions. Reactions with N−H bonds result in formation of cooperative addition products. The thermochemistry of these transformations is strongly dependent on the substrate, with ammonia activation being thermoneutral. This represents the first example of a molecular compound that reversibly activates ammonia via N−H bond scission in solution upon mild heating.
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Affiliation(s)
- Josh Abbenseth
- Department of Chemistry, University of Oxford, 12 Mansfield Road, OX1 3TA, Oxford, UK
| | - Oliver P E Townrow
- Department of Chemistry, University of Oxford, 12 Mansfield Road, OX1 3TA, Oxford, UK
| | - Jose M Goicoechea
- Department of Chemistry, University of Oxford, 12 Mansfield Road, OX1 3TA, Oxford, UK
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Gendy C, Mikko Rautiainen J, Mailman A, Tuononen HM. Low-Valent Germanylidene Anions: Efficient Single-Site Nucleophiles for Activation of Small Molecules. Chemistry 2021; 27:14405-14409. [PMID: 34403540 PMCID: PMC8596740 DOI: 10.1002/chem.202102804] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Indexed: 11/09/2022]
Abstract
Rare mononuclear and helical chain low-valent germanylidene anions supported by cyclic (alkyl)(amino)carbene and hypermetallyl ligands were synthesised by stepwise reduction from corresponding germylene precursors via stable and isolable germanium radicals. The electronic structures of the anions can be described with ylidene and ylidone resonance forms with the Ge-C π-electrons capable of binding even weak electrophiles. The germanylidene anions reacted with CO2 to give μ-CO2 -κC:κO complexes, a rare coordination mode for low-valent germanium and inaccessible for the related neutral germylones. These results implicate low-valent germanylidene anions as efficient single-site nucleophiles for activation of small molecules.
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Affiliation(s)
- Chris Gendy
- Department of ChemistryNanoScience CentreUniversity of JyväskyläP.O. Box. 3540014JyväskyläFinland
| | - J. Mikko Rautiainen
- Department of ChemistryNanoScience CentreUniversity of JyväskyläP.O. Box. 3540014JyväskyläFinland
| | - Aaron Mailman
- Department of ChemistryNanoScience CentreUniversity of JyväskyläP.O. Box. 3540014JyväskyläFinland
| | - Heikki M. Tuononen
- Department of ChemistryNanoScience CentreUniversity of JyväskyläP.O. Box. 3540014JyväskyläFinland
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Yadav R, Weber M, Singh AK, Münzfeld L, Gramüller J, Gschwind RM, Scheer M, Roesky PW. A Structural Diversity of Molecular Alkaline-Earth-Metal Polyphosphides: From Supramolecular Wheel to Zintl Ion. Chemistry 2021; 27:14128-14137. [PMID: 34403183 PMCID: PMC8518058 DOI: 10.1002/chem.202102355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Indexed: 01/31/2023]
Abstract
A series of molecular group 2 polyphosphides has been synthesized by using air-stable [Cp*Fe(η5 -P5 )] (Cp*=C5 Me5 ) or white phosphorus as polyphosphorus precursors. Different types of group 2 reagents such as organo-magnesium, mono-valent magnesium, and molecular calcium hydride complexes have been investigated to activate these polyphosphorus sources. The organo-magnesium complex [(Dipp BDI-Mg(CH3 ))2 ] (Dipp BDI={[2,6-i Pr2 C6 H3 NCMe]2 CH}- ) reacts with [Cp*Fe(η5 -P5 )] to give an unprecedented Mg/Fe-supramolecular wheel. Kinetically controlled activation of [Cp*Fe(η5 -P5 )] by different mono-valent magnesium complexes allowed the isolation of Mg-coordinated formally mono- and di-reduced products of [Cp*Fe(η5 -P5 )]. To obtain the first examples of molecular calcium-polyphosphides, a molecular calcium hydride complex was used to reduce the aromatic cyclo-P5 ring of [Cp*Fe(η5 -P5 )]. The Ca-Fe-polyphosphide is also characterized by quantum chemical calculations and compared with the corresponding Mg complex. Moreover, a calcium coordinated Zintl ion (P7 )3- was obtained by molecular calcium hydride mediated P4 reduction.
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Affiliation(s)
- Ravi Yadav
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
| | - Martin Weber
- Institute of Inorganic ChemistryUniversity of RegensburgUniversitätsstrasse 3193040RegensburgGermany).
| | - Akhil K. Singh
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
| | - Luca Münzfeld
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
| | - Johannes Gramüller
- Institute of Organic ChemistryUniversity of RegensburgUniversitätsstrasse 3193040RegensburgGermany
| | - Ruth M. Gschwind
- Institute of Organic ChemistryUniversity of RegensburgUniversitätsstrasse 3193040RegensburgGermany
| | - Manfred Scheer
- Institute of Inorganic ChemistryUniversity of RegensburgUniversitätsstrasse 3193040RegensburgGermany).
| | - Peter W. Roesky
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
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Abstract
A rare three‐coordinate germanone [IPrN]2Ge=O (IPrN=bis(2,6‐diisopropylphenyl)imidazolin‐2‐imino) was successfully isolated. The germanone has a rather high thermal stability in arene solvent, and no detectable change was observed at 80 °C for at least one week. However, high thermal stability of [IPrN]2Ge=O does not prevent its reactivity toward small molecules. Structural analysis and initial reactivity studies revealed the highly polarized nature of the terminal Ge=O bond. Besides, the addition of phenylacetylene, as well as O‐atom transfer with 2,6‐dimethylphenyl isocyanide make it a mimic of nucleophilic transition‐metal oxides. Mechanism for O‐atom transfer reaction was investigated via DFT calculations, which revealed that the reaction proceeds via a [2+2] cycloaddition intermediate.
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Affiliation(s)
- Xuan-Xuan Zhao
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstraße 4, 85748, Garching bei, München, Germany
| | - Tibor Szilvási
- Department of Chemical and Biological Engineering, University of Alabama, Tuscaloosa, AL, 35487, USA
| | - Franziska Hanusch
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstraße 4, 85748, Garching bei, München, Germany
| | - Shigeyoshi Inoue
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstraße 4, 85748, Garching bei, München, Germany
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15
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Xu M, Kooij B, Wang T, Lin JH, Qu ZW, Grimme S, Stephan DW. Facile Synthesis of Cyanide and Isocyanides from CO. Angew Chem Int Ed Engl 2021; 60:16965-16969. [PMID: 34004079 DOI: 10.1002/anie.202105909] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Indexed: 11/09/2022]
Abstract
The reaction of K[N(SiMe3 )2 ] with 13 CO proceeds in C6 D6 or THF affording K13 CN and O(SiMe3 )2 under mild conditions as confirmed by crystallographic characterization of K(18-crown-6)CN. Similarly reaction of the alkali metal amides, M[N(SiR3 )R'] (M=Li, K; R=Ph, Me; R'=alkyl, aryl) provides the corresponding 13 C labeled isocyanide RN13 C and MOSiR3 , generally in high yields. In some instances, the use of the sterically bulky Ph3 Si-substituent is required to preclude 1,2-silyl migration affording the silylcarbamoyl salt M[Me3 SiC(O)NR']. These reactions have been used to obtain 19 examples of 13 C labelled isocyanides, and several examples of gram scale reactions are reported. The mechanism of the reactions is probed via reliable DFT calculations.
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Affiliation(s)
- Maotong Xu
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario, M5S3H6, Canada
| | - Bastiaan Kooij
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario, M5S3H6, Canada.,Van't Hoff Institute for Molecular Sciences, University of Amsterdam, 1090 GD, Amsterdam, The Netherlands
| | - Tongtong Wang
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario, M5S3H6, Canada.,School of Chemistry, Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, Dalian, 116023, China
| | - Jack H Lin
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario, M5S3H6, Canada
| | - Zheng-Wang Qu
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstrasse 4, 53115, Bonn, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstrasse 4, 53115, Bonn, Germany
| | - Douglas W Stephan
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario, M5S3H6, Canada
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16
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von Wolff N, Robert M. Taming Electron Transfers: From Breaking Bonds to Creating Molecules. CHEM REC 2021; 21:2095-2106. [PMID: 34235842 DOI: 10.1002/tcr.202100151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 11/07/2022]
Abstract
The electron is the ultimate redox reagent to build and reshape molecular structures. Understanding and controlling the parameters underlying dissociative electron transfer (DET) reactivity and its coupling with proton transfer is crucial for combining selectivity, kinetics and energy efficiency in molecular chemistry. Reactivity understanding and mechanistic elements in DET processes are traced back and key examples of current research efforts are presented, demonstrating a large variety of applications. The involvement of DET pathways indeed encompasses a broad range of processes such as photoredox catalysis, CO2 reduction and alcohol oxidation. Interplay between these experimental examples and fundamental mechanistic study provides a powerful path to the understanding of driving force-rate relationships, which is crucial for the development of future generations of energy efficient catalytic schemes in redox organic chemistry.
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Affiliation(s)
- Niklas von Wolff
- Université de Paris, Laboratoire d'Électrocimie Moléculaire, CNRS, F-75006, Paris, France
| | - Marc Robert
- Université de Paris, Laboratoire d'Électrocimie Moléculaire, CNRS, F-75006, Paris, France.,Institut Universitaire de France (IUF), F-75005, Paris, France
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17
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Abstract
Use of a silyl supported stannylene (Mes TerSn(Sit Bu3 ) [Mes Ter=2,6-(2,4,6-Me3 C6 H2 )2 C6 H3 ] enables activation of white phosphorus under mild conditions, which is reversible under UV light. The reaction of a silylene chloride with the activated P4 complex results in facile P-atom transfer. The computational analysis rationalizes the electronic features and high reactivity of the heteroleptic silyl-substituted stannylene in contrast to the previously reported bis(aryl)stannylene.
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Affiliation(s)
- Debotra Sarkar
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research CenterTechnische Universität MünchenLichtenbergstraße 485748GarchingGermany
| | - Catherine Weetman
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research CenterTechnische Universität MünchenLichtenbergstraße 485748GarchingGermany
- Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Dominik Munz
- Department of Chemistry and PharmacyGeneral and Inorganic ChemistryFriedrich-Alexander-University Erlangen-Nuremberg (FAU)Egerlandstraße 191058ErlangenGermany
- Inorganic Chemistry: Coordination ChemistrySaarland University, Geb. C4.166123SaarbrückenGermany
| | - Shigeyoshi Inoue
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research CenterTechnische Universität MünchenLichtenbergstraße 485748GarchingGermany
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18
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Abstract
Since the discovery that the so-called "double-bond" rule could be broken, the field of molecular main group multiple bonds has expanded rapidly. With the majority of homodiatomic double and triple bonds realised within the p-block, along with many heterodiatomic combinations, this Minireview examines the reactivity of these compounds with a particular emphasis on small molecule activation. Furthermore, whilst their ability to act as transition metal mimics has been explored, their catalytic behaviour is somewhat limited. This Minireview aims to highlight the potential of these complexes towards catalytic application and their role as synthons in further functionalisations making them a versatile tool for the modern synthetic chemist.
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Affiliation(s)
- Catherine Weetman
- WestCHEMDepartment of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
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19
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Schwab MM, Himmel D, Kacprzak S, Radtke V, Kratzert D, Weis P, Wernet M, Peter A, Yassine Z, Schmitz D, Scheidt EW, Scherer W, Weber S, Feuerstein W, Breher F, Higelin A, Krossing I. Synthesis, Characterisation and Reactions of Truly Cationic Ni I -Phosphine Complexes. Chemistry 2017; 24:918-927. [PMID: 29155467 DOI: 10.1002/chem.201704436] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Indexed: 11/07/2022]
Abstract
The recently published purely metallo-organic NiI salt [Ni(cod)2 ][Al(ORF )4 ] (1, cod=1,5-cyclooctadiene, RF =C(CF3 )3 ) provides a starting point for a new synthesis strategy leading to NiI phosphine complexes, replacing cod ligands by phosphines. Clearly visible colour changes indicate reactions within minutes, while quantum chemical calculations (PBE0-D3(BJ)/def2-TZVPP) approve exergonic reaction enthalpies in all performed ligand exchange reactions. Hence, [Ni(dppp)2 ][Al(ORF )4 ] (2, dppp=1,3-bis(diphenylphosphino)propane), [Ni(dppe)2 ][Al(ORF )4 ] (3, dppe=1,3-bis(diphenyl-phosphino)ethane), three-coordinate [Ni(PPh3 )3 ][Al(ORF )4 ] (4) and a remarkable two-coordinate NiI phosphine complex [Ni(PtBu3 )2 ][Al(ORF )4 ] (5) were characterised by single crystal X-ray structure analysis. EPR studies were performed, confirming a nickel d9 -configuration in complexes 2, 4 and 5. This result is supported by additional magnetization measurements of 4 and 5. Further investigations by cyclic voltammetry indicate relatively high oxidation potentials for these NiI compounds between 0.7 and 1.7 V versus Fc/Fc+ . Screening reactions with O2 and CO gave first insights on the reaction behaviour of the NiI phosphine complexes towards small molecules with formation of mixed phosphine-CO-NiI complexes and oxidation processes yielding new NiI and/or NiII derivatives. Moreover, 4 reacted with CH2 Cl2 at RT to give a dimeric NiII ylide complex (4 c). As CH2 Cl2 is a rather stable alkyl halide with relatively high C-Cl bond energies, 4 appears to be a suitable reagent for more general C-Cl bond activation reactions.
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Affiliation(s)
- Miriam Mareen Schwab
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
| | - Daniel Himmel
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
| | - Sylwia Kacprzak
- Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 21, 79104, Freiburg, Germany
| | - Valentin Radtke
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
| | - Daniel Kratzert
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
| | - Philippe Weis
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
| | - Melanie Wernet
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
| | - Andreas Peter
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
| | - Zeinab Yassine
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
| | - Dominik Schmitz
- Institut für Physik, Universität Augsburg, Universitätsstraße 1, 86159, Augsburg, Germany
| | - Ernst-Wilhelm Scheidt
- Institut für Physik, Universität Augsburg, Universitätsstraße 1, 86159, Augsburg, Germany
| | - Wolfgang Scherer
- Institut für Physik, Universität Augsburg, Universitätsstraße 1, 86159, Augsburg, Germany
| | - Stefan Weber
- Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 21, 79104, Freiburg, Germany.,Freiburg Institute for Advanced Studies (FRIAS), Albertstr. 19, 79104, Freiburg, Germany
| | - Wolfram Feuerstein
- Division Molecular Chemistry, Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr 15, 76131, Karlsruhe, Germany
| | - Frank Breher
- Division Molecular Chemistry, Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr 15, 76131, Karlsruhe, Germany
| | - Alexander Higelin
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Stefan-Meier-Straße 21, 79104, Freiburg, Germany
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20
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Abstract
Tertiary silane 1H , 2-[(diphenylsilyl)methyl]-6-methylpyridine, reacts with tris(pentafluorophenyl)borane (BCF) to form the intramolecular pyridine-stabilized silylium 1+ -HBCF. The corresponding 2-[(diphenylsilyl)methyl]pyridine, lacking the methyl-group on the pyridine ring, forms classic N(py)→B adduct 2H -BCF featuring an intact silane Si-H fragment. Complex 1+ -HBCF promotes cleavage of the C≡O triple bond in carbon monoxide with double C-Csp2 bond formation, leading to complex 3 featuring a B-(diarylmethyl)-B-aryl-boryloxysilane fragment. Reaction with pinacol generates bis(pentafluorophenyl)methane 4 as isolable product, proving the transition-metal-free deoxygenation of carbon monoxide by this main-group system. Experimental data and DFT calculations support the existence of an equilibrium between the silylium-hydroborate ion pair and the silane-borane mixture that is responsible for the observed reactivity.
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Affiliation(s)
- Marc Devillard
- van ‘t Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
| | - Bas de Bruin
- van ‘t Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
| | - Maxime A. Siegler
- Small Molecule X-ray CrystallographyJohn Hopkins University3400 N Charles StBaltimoreMD21218USA
| | - J. I. van der Vlugt
- van ‘t Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
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21
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Abstract
A comparison of P4 activations mediated by low-valent β-diketiminato (L) cobalt complexes is presented. The formal Co0 source [K2 (L3 Co)2 (μ2 :η1 ,η1 -N2 )] (1) reacts with P4 to form a mixture of the monoanionic complexes [K(thf)6 ][(L3 Co)2 (μ2 :η4 ,η4 -P4 )] (2) and [K(thf)6 ][(L3 Co)2 (μ2 :η3 ,η3 -P3 )] (3). The analogue CoI precursor [L3 Co(tol)] (4 a), however, selectively yields the corresponding neutral derivative [(L3 Co)2 (μ2 :η4 ,η4 -P4 )] (5 a). Compound 5 a undergoes thermal P atom loss to form the unprecedented complex [(L3 Co)2 (μ2 :η3 ,η3 -P3 )] (6). The products 2 and 3 can be obtained selectively by an one-electron reduction of their neutral precursors 5 a and 6, respectively. The electrochemical behaviour of 2, 3, 5 a, and 6 is monitored by cyclic voltammetry and their magnetism is examined by SQUID measurements and the Evans method. The initial CoI -mediated P4 activation is not influenced by applying the structurally different ligands L1 and L2 , which is proven by the formation of the isostructural products [(LCo)2 (μ2 :η4 ,η4 -P4 )] [L=L3 (5 a), L1 (5 b), L2 (5 c)].
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Affiliation(s)
- Fabian Spitzer
- Institut für Anorganische ChemieUniversität RegensburgUniversitätsstrasse 3193040RegensburgGermany
| | - Christian Graßl
- Institut für Anorganische ChemieUniversität RegensburgUniversitätsstrasse 3193040RegensburgGermany
| | - Gábor Balázs
- Institut für Anorganische ChemieUniversität RegensburgUniversitätsstrasse 3193040RegensburgGermany
| | - Eric Mädl
- Institut für Anorganische ChemieUniversität RegensburgUniversitätsstrasse 3193040RegensburgGermany
| | - Martin Keilwerth
- Department of Chemistry and Pharmacy, Inorganic ChemistryFriedrich-Alexander University Erlangen-Nürnberg (FAU)Egerlandstrasse 191058ErlangenGermany
| | - Eva M. Zolnhofer
- Department of Chemistry and Pharmacy, Inorganic ChemistryFriedrich-Alexander University Erlangen-Nürnberg (FAU)Egerlandstrasse 191058ErlangenGermany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic ChemistryFriedrich-Alexander University Erlangen-Nürnberg (FAU)Egerlandstrasse 191058ErlangenGermany
| | - Manfred Scheer
- Institut für Anorganische ChemieUniversität RegensburgUniversitätsstrasse 3193040RegensburgGermany
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22
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Formanuik A, Ortu F, Inman CJ, Kerridge A, Castro L, Maron L, Mills DP. Concomitant Carboxylate and Oxalate Formation From the Activation of CO 2 by a Thorium(III) Complex. Chemistry 2016; 22:17976-17979. [PMID: 27714966 PMCID: PMC5215673 DOI: 10.1002/chem.201604622] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Indexed: 11/14/2022]
Abstract
Improving our comprehension of diverse CO2 activation pathways is of vital importance for the widespread future utilization of this abundant greenhouse gas. CO2 activation by uranium(III) complexes is now relatively well understood, with oxo/carbonate formation predominating as CO2 is readily reduced to CO, but isolated thorium(III) CO2 activation is unprecedented. We show that the thorium(III) complex, [Th(Cp′′)3] (1, Cp′′={C5H3(SiMe3)2‐1,3}), reacts with CO2 to give the mixed oxalate‐carboxylate thorium(IV) complex [{Th(Cp′′)2[κ2‐O2C{C5H3‐3,3′‐(SiMe3)2}]}2(μ‐κ2:κ2‐C2O4)] (3). The concomitant formation of oxalate and carboxylate is unique for CO2 activation, as in previous examples either reduction or insertion is favored to yield a single product. Therefore, thorium(III) CO2 activation can differ from better understood uranium(III) chemistry.
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Affiliation(s)
- Alasdair Formanuik
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Fabrizio Ortu
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Christopher J Inman
- Department of Chemistry and Biochemistry, School of Life Sciences, University of Sussex, Brighton, BN1 9QL, UK
| | - Andrew Kerridge
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK
| | - Ludovic Castro
- LPCNO, CNRA and INSA, Université Paul Sabatier, 135 Avenue de Rangeuil, Toulouse, 31077, France
| | - Laurent Maron
- LPCNO, CNRA and INSA, Université Paul Sabatier, 135 Avenue de Rangeuil, Toulouse, 31077, France
| | - David P Mills
- School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
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23
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Abstract
This contribution describes the reactivities of CO2 , CO, O2 , and ArNC with the pincer-type complexes [(κ(P) ,κ(C) ,κ(P') -POC sp 3OP)NiX] (POC sp 3OP=(R2 POCH2 )2 CH; R=iPr; X=OSiMe3 , NArH; Ar=2,6-iPr2 C6 H3 ). Reaction of the amido derivative with CO2 and CO leads to a simple insertion into the NiN bond to give stable carbamate and carbamoyl derivatives, respectively, the pincer ligand backbone remaining intact in both cases. In contrast, the analogous reactions with the siloxide derivative produced kinetically labile insertion products that either revert to the starting material (in the case of CO2 ) or react further to give the mixed-valent, dinickel species [(POC sp 3OP)Ni(II) {μ,κ(O) ,κ(P) ,κ(P') -OCOCH(CH2 CH2 OPR2 )2 }Ni(0) (CO)2 ]. The zero-valent center in the latter compound is ligated by a new ligand arising from transformation of the POC sp 3OP ligand backbone. The carbonylation and carboxylation of the siloxido derivative also produced minor quantities of a side-product identified as the trinickel species, [{(η(3) -allyl)Ni(μ(O) ,κ(P) -R2 PO)2 }2 Ni], arising from total dismantling of the POC sp 3OP ligand. Similar reactivities were observed with isonitrile, ArNC: reaction with the siloxido derivative resulted in a complex sequence of steps involving initial insertion, a 1,3-hydrogen shift, and an Arbuzov rearrangement to give [Ni(CNAr)4 ] and a methacrylamide based on fragments of the POC sp 3OP ligand. Oxygenation of the amido and siloxido derivatives led to the phosphinate derivative, [(POC sp 3OP)Ni(OP(O)R2 )], arising from oxidative transformation of the original ligand frame; the reaction with the Ni-NHAr derivative also gave ArHNP(O)R2 through a complex NP bond-forming reaction.
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Affiliation(s)
- Jingjun Hao
- Département de chimie, Université de Montréal, 2900 Boul. Edouard-Montpetit, Montréal, Québec, H3C 3 J7 (Canada)
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24
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Rittle J, Peters JC. Fe-N2/CO complexes that model a possible role for the interstitial C atom of FeMo-cofactor (FeMoco). Proc Natl Acad Sci U S A 2013; 110:15898-903. [PMID: 24043796 DOI: 10.1073/pnas.1310153110] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report here a series of four- and five-coordinate Fe model complexes that feature an axial tri(silyl)methyl ligand positioned trans to a substrate-binding site. This arrangement is used to crudely model a single-belt Fe site of the FeMo-cofactor that might bind N2 at a position trans to the interstitial C atom. Reduction of a trigonal pyramidal Fe(I) complex leads to uptake of N2 and subsequent functionalization furnishes an open-shell Fe-diazenido complex. A related series of five-coordinate Fe-CO complexes stable across three redox states is also described. Spectroscopic, crystallographic, and Density Functional Theory (DFT) studies of these complexes suggest that a decrease in the covalency of the Fe-C(alkyl) interaction occurs upon reduction and substrate binding. This leads to unusually long Fe-C(alkyl) bond distances that reflect an ionic Fe-C bond. The data presented are contextualized in support of a hypothesis wherein modulation of a belt Fe-C interaction in the FeMo-cofactor facilitates substrate binding and reduction.
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25
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Abstract
Nickel-containing carbon monoxide dehydrogenases, acetyl-CoA synthases, nickel-iron hydrogenases, and diron hydrogenases are distinct metalloenzymes yet they share a number of important characteristics. All are O(2)-sensitive, with active-sites composed of iron and/or nickel ions coordinated primarily by sulfur ligands. In each case, two metals are juxtaposed at the "heart" of the active site, within range of forming metal-metal bonds. These active-site clusters exhibit multielectron redox abilities and must be reductively activated for catalysis. Reduction potentials are milder than expected based on formal oxidation state changes. When reductively activated, each cluster attacks an electrophilic substrate via an oxidative addition reaction. This affords a two-electron-reduced substrate bound to one or both metals of an oxidized cluster. M-M bonds have been established in hydrogenases where they serve to initiate the oxidative addition of protons and perhaps stabilize active sites in multiple redox states. The same may be true of the CODH and ACS active sites-Ni-Fe and Ni-Ni bonds in these sites may play critical roles in catalysis, stabilizing low-valence states and initiating oxidative addition of CO(2) and methyl group cations, respectively. In this article, the structural and functional commonalities of these metalloenzyme active sites are described, and the case is made for the formation and use of metal-metal bonds in each enzyme mentioned. As a post-script, the importance of Fe-Fe bonds in the nitrogenase FeMoco active site is discussed.
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Affiliation(s)
- Paul A Lindahl
- Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA.
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