1
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Landrini M, De Paolis E, Macchioni A, Tensi L, Hrobárik P, Rocchigiani L. Ion pairing in cationic Au(I)(µ‐H)2WCp2 bimetallic dihydrides. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Martina Landrini
- University of Perugia: Universita degli Studi di Perugia Department of Chemistry, Biology and Biotechnology ITALY
| | - Elena De Paolis
- University of Perugia: Universita degli Studi di Perugia Department of Chemistry, Biology and Biotechnology ITALY
| | - Alceo Macchioni
- University of Perugia: Universita degli Studi di Perugia Department of Chemistry, Biology and Biotechnology ITALY
| | - Leonardo Tensi
- University of Perugia: Universita degli Studi di Perugia Department of Chemistry, Biology and Biotechnology ITALY
| | - Peter Hrobárik
- Comenius University in Bratislava Faculty of Natural Sciences: Univerzita Komenskeho v Bratislave Prirodovedecka fakulta Department of Inorganic Chemistry SLOVAKIA
| | - Luca Rocchigiani
- University of Perugia: Universita degli Studi di Perugia Department of Chemistry, Biology and Biotechnology Via Elce di sotto, 8 06123 Perugia ITALY
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2
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Mo L, Barr HI, Odom AL. Investigation of Phosphine Donor Properties to Vanadium(V) Nitrides. RESULTS IN CHEMISTRY 2022. [DOI: 10.1016/j.rechem.2022.100344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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3
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Aldrich KE, Livshits MY, Stromberg LR, Janicke MT, Nhu Lam M, Stein B, Wagner GL, Abergel RJ, Mukundan H, Kozimor SA, Lilley LM. Th IV-Desferrioxamine: characterization of a fluorescent bacterial probe. Dalton Trans 2021; 50:15310-15320. [PMID: 34636377 DOI: 10.1039/d1dt02177j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Diversifying our ability to guard against emerging pathogenic threats is essential for keeping pace with global health challenges, including those presented by drug-resistant bacteria. Some modern diagnostic and therapeutic innovations to address this challenge focus on targeting methods that exploit bacterial nutrient sequestration pathways, such as the desferrioxamine (DFO) siderophore used by Staphylococcus aureus (S. aureus) to sequester FeIII. Building on recent studies that have shown DFO to be a versatile vehicle for chemical delivery, we show proof-of-principle that the FeIII sequestration pathway can be used to deliver a potential radiotherapeutic. Our approach replaces the FeIII nutrient sequestered by H4DFO+ with ThIV and made use of a common fluorophore, FITC, which we covalently bonded to DFO to provide a combinatorial probe for simultaneous chelation paired with imaging and spectroscopy, H3DFO_FITC. Combining insight provided from FITC-based imaging with characterization by NMR spectroscopy, we demonstrated that the fluorescent DFO_FITC conjugate retained the ThIV chelation properties of native H4DFO+. Fluorescence microscopy with both [Th(DFO_FITC)] and [Fe(DFO_FITC)] complexes showed similar uptake by S. aureus and increased intercellular accumulation as compared to the FITC and unchelated H3DFO_FITC controls. Collectively, these results demonstrate the potential for the newly developed H3DFO_FITC conjugate to be used as a targeting vector and bacterial imaging probe for S. aureus. The results presented within provide a framework to expand H4DFO+ and H3DFO_FITC to relevant radiotherapeutics (like 227Th).
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Affiliation(s)
| | | | | | | | - Mila Nhu Lam
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA.
| | - Benjamin Stein
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA.
| | | | - Rebecca J Abergel
- Department of Chemistry, University of California, Berkeley, California, 94720, USA
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4
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Khan FST, Waldbusser AL, Carrasco MC, Pourhadi H, Hematian S. Synthetic, spectroscopic, structural, and electrochemical investigations of ferricenium derivatives with weakly coordinating anions: ion pairing, substituent, and solvent effects. Dalton Trans 2021; 50:7433-7455. [PMID: 33970173 DOI: 10.1039/d1dt01192h] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A facile and effective strategy for the preparation of a series of ferricenium complexes bearing either electron-donating or electron-withdrawing substituents with weakly coordinating anions such as [B(C6F5)4]- or SbF6- is reported. These systems were thoroughly investigated for their ground state electronic structures in both solution and solid states using infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies as well as single crystal X-ray crystallography and electrochemical measurements. The X-ray structures of the six electron-deficient ferricenium derivatives are of particular interest as only a handful (∼5) of such derivatives have been structurally characterized to date. Comparison of the structural data for both neutral and oxidized derivatives reveals that the nature of the substituents on the cyclopentadienyl (Cp) ligands displays a more significant impact on the metal-ligand separations (FeCt) in the oxidized species than in their neutral analogs. Our 1H-NMR measurements corroborate that in the neutral ferrocene derivatives, electron-donating ring substitutions lead to a greater shielding of the ring protons while electron-withdrawing groups via induction deshield the nearby ring protons. However, the data for the paramagnetic ferricenium derivatives reveals that this substitutional behavior is more complex and fundamentally reversed, which is further supported by our structural studies. We ascribe this reversal of behavior in the ferricenium derivatives to the δ back-donation from the iron atom into the Cp rings which can lead to the overall shielding of the ring protons. Interestingly, our NMR results for the electron-deficient ferricenium derivatives in solution also indicate a direct correlation between the solvent dielectric constant and the energy barrier for rotation around the metal-ligand bond in these systems, whereas such a correlation is absent or not significant in the case of the electron-rich ferricenium species or the corresponding neutral ferrocene analogs. In this work, we also present the electrochemical behavior of the corresponding ferricenium/ferrocene redox couples including potential values (E1/2), peak-to-peak separation (ΔE1/2), and diffusion coefficients (D) of the redox active species in order to provide a concise outline of these data in one place. Our electrochemical studies involved three different solvents and two supporting electrolytes. Notably, our findings point to the significant effect of ion-pairing in lowering the energy necessary for reduction of the ferricenium ion and E1/2 in lower-polarity media. This has significant implications in applications of the ferrocene or ferricenium derivatives as redox agents in low-polarity solvents where an accurate determination of redox potential is critical.
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Affiliation(s)
- Firoz Shah Tuglak Khan
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Amy L Waldbusser
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Maria C Carrasco
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Hadi Pourhadi
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Shabnam Hematian
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
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5
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Martı Nez-Alonso M, Sanz P, Ortega P, Espino G, Jalón FA, Martín M, Rodrı Guez AM, López JA, Tejel C, Manzano BR. Analysis of Ion Pairing in Solid State and Solution in p-Cymene Ruthenium Complexes. Inorg Chem 2020; 59:14171-14183. [PMID: 32930592 DOI: 10.1021/acs.inorgchem.0c01951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The importance of ion pairing in different fields of chemistry is widely recognized. In this work, we have synthesized a set of cationic p-cymene ruthenium complexes of general formula [(p-cym)Ru(L')(κ2-O^N-L)]X (p-cym = p-cymene; L' = N-methylimidazole (MeIm), N-ethylpiperidylimidazole (EpipIm), 1,3,5-triaza-7-phosphaadamantane (PTA); L = 2-(1H-benzimidazol-2-yl)phenolato (L1), 2-(1,3-benzothiazol-2-yl)phenolato (L2); X = Cl-, BF4-, OTf-, BPh4-). X-ray diffraction studies on selected complexes revealed relatively strong anion-cation interactions in the solid state mainly based on N-H···X (X = Cl, F, O) and C-H···π interactions, also observed in the DFT-modeled complexes in the gas phase. Moreover, NMR studies showed that they exist as intimate ion pairs in solution and, remarkably, as head-to-tail quadruples in the particular case of the cation [(p-cym)Ru(MeIm)(κ2- O^N-L1)]+ ([1]+) with Cl- and BPh4- as counteranions. Furthermore, a value of ΔG = -2.9 kcal mol-1 at 299 K has been estimated for the equilibrium {[1]BPh4···[1]BPh4} ⇆ 2{[1]+···BPh4-} in concentrated CDCl3 solutions. In addition, preliminary studies concerning the cytotoxic properties against HeLa cell lines of the derivatives suggested a positive effect derived from the presence of the lipophilic BPh4- anion and also from the NH group of the benzimidazolyl fragment.
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Affiliation(s)
- Marta Martı Nez-Alonso
- University de Burgos. Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s. n., 09001-Burgos, Spain
| | - Pedro Sanz
- University de Castilla-La Mancha, Departamento de Química Inorgánica, Orgánica y Bioquímica, CRIB, Fac. de Ciencias y Tecnologías Químicas, Avda. C. J. Cela, 10, 13071-Ciudad Real, Spain
| | - Paula Ortega
- University de Castilla-La Mancha, Departamento de Química Inorgánica, Orgánica y Bioquímica, CRIB, Fac. de Ciencias y Tecnologías Químicas, Avda. C. J. Cela, 10, 13071-Ciudad Real, Spain
| | - Gustavo Espino
- University de Burgos. Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s. n., 09001-Burgos, Spain
| | - Félix A Jalón
- University de Castilla-La Mancha, Departamento de Química Inorgánica, Orgánica y Bioquímica, CRIB, Fac. de Ciencias y Tecnologías Químicas, Avda. C. J. Cela, 10, 13071-Ciudad Real, Spain
| | - Mairena Martín
- University de Castilla-La Mancha, Departamento de Química Inorgánica, Orgánica y Bioquímica, CRIB, Fac. de Ciencias y Tecnologías Químicas, Avda. C. J. Cela, 10, 13071-Ciudad Real, Spain
| | - Ana M Rodrı Guez
- University de Castilla-La Mancha, Departamento de Química Inorgánica, Orgánica y Bioquímica, IRICA, Escuela Técnica Superior de Ingenieros Industriales, Avda. C. J. Cela, 3, 13071-Ciudad Real, Spain
| | - José A López
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009-Zaragoza, Spain
| | - Cristina Tejel
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009-Zaragoza, Spain
| | - Blanca R Manzano
- University de Castilla-La Mancha, Departamento de Química Inorgánica, Orgánica y Bioquímica, CRIB, Fac. de Ciencias y Tecnologías Químicas, Avda. C. J. Cela, 10, 13071-Ciudad Real, Spain
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6
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Wang D, Jahan F, Meise KJ, Lindeman SV, Gardinier JR. Silver(I) and Copper(I) Complexes of Semi‐Bulky Nitrogen‐Confused
C
‐Scorpionates. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000173] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Denan Wang
- Department of Chemistry Marquette University 1414 W. Clybourne St 53233 Milwaukee WI USA
| | - Fathiya Jahan
- Department of Chemistry Marquette University 1414 W. Clybourne St 53233 Milwaukee WI USA
| | - Kristen J. Meise
- Department of Chemistry Marquette University 1414 W. Clybourne St 53233 Milwaukee WI USA
| | - Sergey V. Lindeman
- Department of Chemistry Marquette University 1414 W. Clybourne St 53233 Milwaukee WI USA
| | - James R. Gardinier
- Department of Chemistry Marquette University 1414 W. Clybourne St 53233 Milwaukee WI USA
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7
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Aldrich KE, Kansal D, Odom AL. Catalyst design insights from modelling a titanium-catalyzed multicomponent reaction. Faraday Discuss 2019; 220:208-230. [PMID: 31528974 DOI: 10.1039/c9fd00033j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High oxidation state transition metal catalysis touches our daily lives through bulk chemical production, e.g. olefin polymerization, and through specialty chemical reactions common in organic synthesis, e.g. the Sharpless asymmetric epoxidation and olefin dihydroxylation. Our group has been expanding the reaction chemistry of titanium(iv) to produce a host of nitrogen-based heterocycles via multicomponent coupling reactions. One such multicomponent coupling reaction discovered in our laboratory is iminoamination, involving an amine, an alkyne, and an isonitrile. However, the experimental modeling of high oxidation state reactions lags far behind that of low oxidation state systems, where a great deal is known about ligands, their donor properties and how their structures affect catalysis. As a result, we have developed an experimental method for determining the donor abilities of anionic ligands on high oxidation state systems, which is based on the chromium(vi) nitride system NCr(NiPr2)2X, where X = the ligand being interrogated. The parameters obtained are simply called ligand donor parameters (LDP). In this contribution, a detailed optimization of the Ti(NMe2)2(dpm)-catalyzed iminoamination reaction was carried out, where dpm = 5,5-dimethyldipyrrolylmethane. During the course of these studies, dimeric {Ti(μ-N-tolyl)(dpm)}2 was isolated, which is proposed as the resting state of the catalyst. To destabilize this resting state, a more electron-rich bis(aryloxide) catalyst system was investigated. The more electron-rich system is somewhat more active for iminoamination under some conditions; however, the catalyst is prone to disproportionation. A study of heteroleptic titanium complexes revealed that the disproportionation equilibrium constant can be effectively modeled as a function of the square of the difference in LDP between the ligands, (ΔLDP)2. Using this methodology, one can estimate the stability of titanium complexes toward disproportionation.
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Affiliation(s)
- Kelly E Aldrich
- Department of Chemistry, Michigan State University, 578 S. Shaw Ln, East Lansing, MI 48824, USA.
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8
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Tang Y, Yu B. Coinage Metal (Bisfluorosulfonyl)imide Complexes: Preparation, Characterization, and Catalytic Applications. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201901058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Yu Tang
- State Key Laboratory of Bioorganic and Natural Products Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road 200032 Shanghai China
| | - Biao Yu
- State Key Laboratory of Bioorganic and Natural Products Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road 200032 Shanghai China
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9
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Citek C, Oyala PH, Peters JC. Mononuclear Fe(I) and Fe(II) Acetylene Adducts and Their Reductive Protonation to Terminal Fe(IV) and Fe(V) Carbynes. J Am Chem Soc 2019; 141:15211-15221. [PMID: 31430146 PMCID: PMC6800224 DOI: 10.1021/jacs.9b06987] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The activity of nitrogenase enzymes, which catalyze the conversion of atmospheric dinitrogen to bioavailable ammonia, is most commonly assayed by the reduction of acetylene gas to ethylene. Despite the practical importance of acetylene as a substrate, little is known concerning its binding or activation in the iron-rich active site. "Fischer-Tropsch" type coupling of non-native C1 substrates to higher-order C≥2 products is also known for nitrogenase, though potential metal-carbon multiply bonded intermediates remain underexplored. Here we report the activation of acetylene gas at a mononuclear tris(phosphino)silyl-iron center, (SiP3)Fe, to give Fe(I) and Fe(II) side-on adducts, including S = 1/2 FeI(η2-HCCH); the latter is characterized by pulse EPR spectroscopy and DFT calculations. Reductive protonation reactions with these compounds converge at stable examples of unusual, formally iron(IV) and iron(V) carbyne complexes, as in diamagnetic (SiP3)Fe≡CCH3 and the paramagnetic cation S = 1/2 [(SiP3)Fe≡CCH3]+. Both alkylcarbyne compounds possess short Fe-C triple bonds (approximately 1.7 Å) trans to the anchoring silane. Pulse EPR experiments, X-band ENDOR and HYSCORE, reveal delocalization of the iron-based spin onto the α-carbyne nucleus in carbon p-orbitals. Furthermore, isotropic coupling of the distal β-CH3 protons with iron indicates hyperconjugation with the spin/hole character on the Fe≡CCH3 unit. The electronic structures of (SiP3)Fe≡CCH3 and [(SiP3)Fe≡CCH3]+ are discussed in comparison to previously characterized, but heterosubstituted, iron carbynes, as well as a hypothetical nitride species, (SiP3)Fe≡N. Such comparisons are germane to the consideration of formally high-valent, multiply bonded Fe≡C and/or Fe≡N intermediates in synthetic or biological catalysis by iron.
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Affiliation(s)
- Cooper Citek
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Paul H. Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jonas C. Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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10
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Aldrich KE, Billow BS, Staples RJ, Odom AL. Phosphine interactions with high oxidation state metals. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.11.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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11
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Wozniak DI, Hicks AJ, Sabbers WA, Dobereiner GE. Imidazolyl-phenyl (IMP) anions: a modular structure for tuning solubility and coordinating ability. Dalton Trans 2019; 48:14138-14155. [DOI: 10.1039/c9dt03511g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The effect of counteranion upon a cation's solution-phase reactivity depends on a subtle interplay of weak interactions.
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12
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Heimann JE, Bernskoetter WH, Hazari N, Mayer JM. Acceleration of CO 2 insertion into metal hydrides: ligand, Lewis acid, and solvent effects on reaction kinetics. Chem Sci 2018; 9:6629-6638. [PMID: 30310595 PMCID: PMC6115618 DOI: 10.1039/c8sc02535e] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 07/05/2018] [Indexed: 11/21/2022] Open
Abstract
The insertion of CO2 into metal hydrides and the microscopic reverse decarboxylation of metal formates are important elementary steps in catalytic cycles for both CO2 hydrogenation to formic acid and methanol as well as formic acid and methanol dehydrogenation. Here, we use rapid mixing stopped-flow techniques to study the kinetics and mechanism of CO2 insertion into transition metal hydrides. The investigation finds that the most effective method to accelerate the rate of CO2 insertion into a metal hydride can be dependent on the nature of the rate-determining transition state (TS). We demonstrate that for an innersphere CO2 insertion reaction, which is proposed to have a direct interaction between CO2 and the metal in the rate-determining TS, the rate of insertion increases as the ancillary ligand becomes more electron rich or less sterically bulky. There is, however, no rate enhancement from Lewis acids (LA). In comparison, we establish that for an outersphere CO2 insertion, proposed to proceed with no interaction between CO2 and the metal in the rate-determining TS, there is a dramatic LA effect. Furthermore, for both inner- and outersphere reactions, we show that there is a small solvent effect on the rate of CO2 insertion. Solvents that have higher acceptor numbers generally lead to faster CO2 insertion. Our results provide an experimental method to determine the pathway for CO2 insertion and offer guidance for rate enhancement in CO2 reduction catalysis.
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Affiliation(s)
- Jessica E Heimann
- Department of Chemistry , Yale University , P. O. Box 208107 , New Haven , Connecticut 06520 , USA .
| | | | - Nilay Hazari
- Department of Chemistry , Yale University , P. O. Box 208107 , New Haven , Connecticut 06520 , USA .
| | - James M Mayer
- Department of Chemistry , Yale University , P. O. Box 208107 , New Haven , Connecticut 06520 , USA .
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13
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Oßwald S, Casper LA, Anders P, Schiebel E, Demeshko S, Winter RF. Electrochemical, Spectroelectrochemical, Mößbauer, and EPR Spectroscopic Studies on Ferrocenyl-Substituted Tritylium Dyes. Chemistry 2018; 24:12524-12538. [PMID: 29904938 DOI: 10.1002/chem.201802364] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/12/2018] [Indexed: 11/09/2022]
Abstract
Four monoferrocenyl tritylium derivatives with donor-substituted (OMe, NMe2 ) aryl rings are reported, along with their spectroscopic and electrochemical properties. All the complexes show a one-electron reduction and a quasi-reversible ferrocene oxidation at a very positive potential. Small quadrupole splittings, ΔEQ , in Mößbauer spectra agree with highly electron-deficient ferrocenes. Comparison of the experimental half-wave potentials for ferrocene oxidation, E1/2 (Fc/Fc+ ), with those estimated from established correlations of E1/2 (Fc/Fc+ ) with ΔEQ indicates that the E1/2 values of the anisyl-substituted congeners FcOMe+ and FcMeOMe+ are affected by Coulombic repulsion between the positive charges at the Fe ion and the neighboring methylium site. Electronic spectra are recorded and interpreted with the aid of quantum chemical calculations. UV/Vis spectroelectrochemical measurements as well as chemical reduction provide insight into the redox-induced color changes upon ferrocene oxidation or upon reduction to the neutral trityl radicals. The neutral radicals reversibly form EPR-silent dimers. This process is studied by temperature-dependent EPR spectroscopy, and thermodynamic data for their dimerization are determined. Experimental and quantum chemical data suggest that the dimers assume classical hexaarylethane structures as opposed to normal or "offset" Jacobson-Nauta-type structures.
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Affiliation(s)
- Steffen Oßwald
- Fachbereich Chemie, Universität Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Larissa A Casper
- Fachbereich Chemie, Universität Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Patrick Anders
- Fachbereich Chemie, Universität Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Eva Schiebel
- Fachbereich Chemie, Universität Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Serhiy Demeshko
- Fakultät für Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Rainer F Winter
- Fachbereich Chemie, Universität Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
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14
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Wozniak DI, Sabbers WA, Weerasiri KC, Dinh LV, Quenzer JL, Hicks AJ, Dobereiner GE. Comparing Interactions of a Three-Coordinate Pd Cation with Common Weakly Coordinating Anions. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Derek I. Wozniak
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - William A. Sabbers
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Kushan C. Weerasiri
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Luckym V. Dinh
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Jacqueline L. Quenzer
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Andrew J. Hicks
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Graham E. Dobereiner
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
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15
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Gardinier JR, Meise KJ, Jahan F, Lindeman SV. Reaction Chemistry of Silver(I) Trifluoromethanesulfonate Complexes of Nitrogen-Confused C-Scorpionates. Inorg Chem 2018; 57:1572-1589. [PMID: 29359926 DOI: 10.1021/acs.inorgchem.7b02927] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Two new C-scorpionate ligands with a bis(3,5-dimethylpyrazol-1-yl)methyl group bound to the 3 position of either an N-tosyl (TsL*) or an N-H pyrazole (HL*) ring have been prepared. The silver(I) complexes of these new ligands and the two previously reported analogous ligands with unsubstituted bis(pyrazol-1-yl)methyl groups (TsL and HL) in both 1:1 and 2:1 ligand/metal ratios were investigated to explore the effects of ligand sterics on their physical and chemical properties. The structurally characterized derivatives of the type [Ag(L)2](OTf) are four-coordinate, where the confused pyrazolyl is not bound to the metal. On the other hand, three 1:1 complexes [Ag(L)](OTf) had all pyrazolyls bound, while the μ-κ1,κ1-TsL derivative had an unbound confused pyrazolyl. The molecularity of the latter four ranged from polymeric to dimeric to monomeric in the solid with increasing steric bulk of the ligand. The utility of these complexes in stoichiometric ligand-transfer reactions and in styrene aziridination was demonstrated. Thus, tricarbonylmanganese(I) complexes were prepared as kinetically inert models for comparative solution diffusion NMR studies. Also, [Fe(HL)2](OTf)2 was prepared for similar reasons and to compare the effects of anion on spin-crossover properties.
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Affiliation(s)
- James R Gardinier
- Department of Chemistry, Marquette University , Milwaukee, Wisconsin 53201-1881, United States
| | - Kristin J Meise
- Department of Chemistry, Marquette University , Milwaukee, Wisconsin 53201-1881, United States
| | - Fathiya Jahan
- Department of Chemistry, Marquette University , Milwaukee, Wisconsin 53201-1881, United States
| | - Sergey V Lindeman
- Department of Chemistry, Marquette University , Milwaukee, Wisconsin 53201-1881, United States
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