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Chen JY, Li M, Liao RZ. Mechanistic Insights into Photochemical CO 2 Reduction to CH 4 by a Molecular Iron-Porphyrin Catalyst. Inorg Chem 2023. [PMID: 37279181 DOI: 10.1021/acs.inorgchem.3c00402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Iron tetraphenylporphyrin complex modified with four trimethylammonium groups (Fe-p-TMA) is found to be capable of catalyzing the eight-electron eight-proton reduction of CO2 to CH4 photochemically in acetonitrile. In the present work, density functional theory (DFT) calculations have been performed to investigate the reaction mechanism and to rationalize the product selectivity. Our results revealed that the initial catalyst Fe-p-TMA ([Cl-Fe(III)-LR4]4+, where L = tetraphenylporphyrin ligand with a total charge of -2, and R4 = four trimethylammonium groups with a total charge of +4) undergoes three reduction steps, accompanied by the dissociation of the chloride ion to form [Fe(II)-L••2-R4]2+. [Fe(II)-L••2-R4]2+, bearing a Fe(II) center ferromagnetically coupled with a tetraphenylporphyrin diradical, performs a nucleophilic attack on CO2 to produce the 1η-CO2 adduct [CO2•--Fe(II)-L•-R4]2+. Two intermolecular proton transfer steps then take place at the CO2 moiety of [CO2•--Fe(II)-L•-R4]2+, resulting in the cleavage of the C-O bond and the formation of the critical intermediate [Fe(II)-CO]4+ after releasing a water molecule. Subsequently, [Fe(II)-CO]4+ accepts three electrons and one proton to generate [CHO-Fe(II)-L•-R4]2+, which finally undergoes a successive four-electron-five-proton reduction to produce methane without forming formaldehyde, methanol, or formate. Notably, the redox non-innocent tetraphenylporphyrin ligand was found to play an important role in CO2 reduction since it could accept and transfer electron(s) during catalysis, thus keeping the ferrous ion at a relatively high oxidation state. Hydrogen evolution reaction via the formation of Fe-hydride ([Fe(II)-H]3+) turns out to endure a higher total barrier than the CO2 reduction reaction, therefore providing a reasonable explanation for the origin of the product selectivity.
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Affiliation(s)
- Jia-Yi Chen
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Man Li
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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Yang Q, Li Q, Scheiner S. Diboron Bonds Between BX 3 (X=H, F, CH 3 ) and BYZ 2 (Y=H, F; Z=CO, N 2 , CNH). Chemphyschem 2021; 22:1461-1469. [PMID: 34089563 DOI: 10.1002/cphc.202100332] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/27/2021] [Indexed: 11/12/2022]
Abstract
The ability of B atoms on two different molecules to engage with one another in a noncovalent diboron bond is studied by ab initio calculations. Due to electron donation from its substituents, the trivalent B atom of BYZ2 (Z=CO, N2 , and CNH; Y=H and F) has the ability to in turn donate charge to the B of a BX3 molecule (X=H, F, and CH3 ), thus forming a B⋅⋅⋅B diboron bond. These bonds are of two different strengths and character. BH(CO)2 and BH(CNH)2 , and their fluorosubstituted analogues BF(CO)2 and BF(CNH)2 , engage in a typical noncovalent bond with B(CH3 )3 and BF3 , with interaction energies in the 3-8 kcal/mol range. Certain other combinations result in a much stronger diboron bond, in the 26-44 kcal/mol range, and with a high degree of covalent character. Bonds of this type occur when BH3 is added to BH(CO)2 , BH(CNH)2 , BH(N2 )2 , and BF(CO)2 , or in the complexes of BH(N2 )2 with B(CH3 )3 and BF3 . The weaker noncovalent bonds are held together by roughly equal electrostatic and dispersion components, complemented by smaller polarization energy, while polarization is primarily responsible for the stronger ones.
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Affiliation(s)
- Qingqing Yang
- The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai, 264005, P. R. China
| | - Qingzhong Li
- The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai, 264005, P. R. China
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, 84322-0300, USA
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3
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Junxi L, Yu D, Jun B, Zhenhua L, Xiaoe W, Qiong S. Theoretical study of isomers XBEY, BEXY, and XYBE (E = N, P, and As, and X, Y = F and Cl): Substituent effect. COMPUT THEOR CHEM 2020. [DOI: 10.1016/j.comptc.2020.112873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Fantuzzi F, Wolff W, Quitián-Lara HM, Boechat-Roberty HM, Hilgers G, Rudek B, Nascimento MAC. Unexpected reversal of stability in strained systems containing one-electron bonds. Phys Chem Chem Phys 2019; 21:24984-24992. [PMID: 31709438 DOI: 10.1039/c9cp04964a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Ring strain energy is a very well documented feature of neutral cycloalkanes, and influences their structural, thermochemical and reactivity properties. In this work, we apply density functional theory and high-level coupled cluster calculations to describe the geometry and relative stability of C6H12+˙ radical cations, whose cyclic isomers are prototypes of singly-charged cycloalkanes. Molecular ions with the mentioned stoichiometry were produced via electron impact experiments using a gaseous cyclohexane sample (20-2000 eV). From our calculations, in addition to structures that resemble linear and branched alkenes as well as distinct conformers of cyclohexane, we have found low-lying species containing three-, four- and five-membered rings with the presence of an elongated C-C bond. Remarkably, the stability trend of these ring-bearing radical cations is anomalous, and the three-membered species are up to 11.3 kcal mol-1 more stable than the six-membered chair structure. Generalized Valence Bond calculations and the Spin Coupled theory with N electrons and M orbitals were used in conjunction with the Generalized Product Function Energy Partitioning (GPF-EP) method and Interference Energy Analysis (IEA) to describe the chemical bonding in such moieties. Our results confirm that these elongated C-C motifs are one-electron sigma bonds. Our calculations also reveal the effects that drive thermochemical preference of strained systems over their strained-free isomers, and the origin of the unusual stability trend observed for cycloalkane radical cations.
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Affiliation(s)
- Felipe Fantuzzi
- Instituto de Química, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos 149, 21941-909, Rio de Janeiro, Brazil. and Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany and Institute for Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg, Emil-Fischer-Straße 42, 97074 Würzburg, Germany
| | - Wania Wolff
- Instituto de Física, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos 149, 21941-972, Rio de Janeiro, Brazil.
| | - Heidy M Quitián-Lara
- Observatório do Valongo, Universidade Federal do Rio de Janeiro, Ladeira do Pedro Antônio 43, 20080-090, Rio de Janeiro, Brazil
| | - Heloisa M Boechat-Roberty
- Observatório do Valongo, Universidade Federal do Rio de Janeiro, Ladeira do Pedro Antônio 43, 20080-090, Rio de Janeiro, Brazil
| | - Gerhard Hilgers
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Benedikt Rudek
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany and Massachusetts General Hospital, Department of Radiation Oncology, 30 Fruit Street, Boston, MA 02114, USA
| | - Marco Antonio Chaer Nascimento
- Instituto de Química, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos 149, 21941-909, Rio de Janeiro, Brazil.
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Nance PJ, Thompson NB, Oyala PH, Peters JC. Zerovalent Rhodium and Iridium Silatranes Featuring Two-Center, Three-Electron Polar σ Bonds. Angew Chem Int Ed Engl 2019; 58:6220-6224. [PMID: 30759317 DOI: 10.1002/anie.201814206] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/26/2019] [Indexed: 12/19/2022]
Abstract
Species with 2-center, 3-electron (2c/3e- ) σ bonds are of interest owing to their fascinating electronic structures and potential for interesting reactivity patterns. Report here is the synthesis and characterization of a pair of zerovalent (d9 ) trigonal pyramidal Rh and Ir complexes that feature 2c/3e- σ bonds to the Si atom of a tripodal tris(phosphine)silatrane ligand. X-ray diffraction, continuous wave and pulse electron paramagnetic resonance, density-functional theory calculations, and reactivity studies have been used to characterize these electronically distinctive compounds. The data available highlight a 2c/3e- bonding framework with a σ*-SOMO of metal 4- or 5dz 2 parentage that is partially stabilized by significant mixing with Si (3pz ) and metal (5- or 6pz ) orbitals. Metal-ligand covalency thus buffers the expected destabilization of transition-metal (TM)-silyl σ*-orbitals by d-p mixing, affording well-characterized examples of TM-main group, and hence polar, 2c/3e- σ "half-bonds".
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Affiliation(s)
- Patricia J Nance
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Niklas B Thompson
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Jonas C Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
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Nance PJ, Thompson NB, Oyala PH, Peters JC. Zerovalent Rhodium and Iridium Silatranes Featuring Two‐Center, Three‐Electron Polar σ Bonds. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201814206] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Patricia J. Nance
- Division of Chemistry and Chemical EngineeringCalifornia Institute of Technology Pasadena CA 91125 USA
| | - Niklas B. Thompson
- Division of Chemistry and Chemical EngineeringCalifornia Institute of Technology Pasadena CA 91125 USA
| | - Paul H. Oyala
- Division of Chemistry and Chemical EngineeringCalifornia Institute of Technology Pasadena CA 91125 USA
| | - Jonas C. Peters
- Division of Chemistry and Chemical EngineeringCalifornia Institute of Technology Pasadena CA 91125 USA
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Taylor JW, McSkimming A, Moret ME, Harman WH. A Molecular Boroauride: A Donor-Acceptor Complex of Anionic Gold. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201703235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jordan W. Taylor
- Department of Chemistry; University of California-Riverside; Riverside CA 92521 USA
| | - Alex McSkimming
- Department of Chemistry; University of California-Riverside; Riverside CA 92521 USA
| | - Marc-Etienne Moret
- Organic Chemistry & Catalysis; Debye Institute for Nanomaterials Science; Utrecht University; Universiteitsweg 99 3584 CG Utrecht The Netherlands
| | - W. Hill Harman
- Department of Chemistry; University of California-Riverside; Riverside CA 92521 USA
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Taylor JW, McSkimming A, Moret ME, Harman WH. A Molecular Boroauride: A Donor-Acceptor Complex of Anionic Gold. Angew Chem Int Ed Engl 2017; 56:10413-10417. [PMID: 28589611 DOI: 10.1002/anie.201703235] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Indexed: 11/06/2022]
Abstract
Gold is unique among the transition metals in that it is stable as an isolated anion (auride). Despite this fact, the coordination chemistry of anionic gold is virtually nonexistent, and this unique oxidation state is not readily exploited in conventional solution chemistry owing to its high reactivity. Through the use of a new molecular scaffold based on diboraanthracene (B2 P2 , 1), we have overcome these issues by avoiding the intermediacy of zerovalent gold and stabilizing the highly reduced gold anion through acceptor interactions. We have thus synthesized a molecular boroauride [(B2 P2 )Au]- ([2]- ) and showed its reversible conversion between Au-I and AuI states. Through a combination of spectroscopic and computational studies, we show the neutral state to be a AuI complex with a ligand radical anion. Bonding analyses (NBO and QTAIM) and the isolobal relationship between gold and hydrogen provide support for the description of [2]- as a boroauride complex.
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Affiliation(s)
- Jordan W Taylor
- Department of Chemistry, University of California-Riverside, Riverside, CA, 92521, USA
| | - Alex McSkimming
- Department of Chemistry, University of California-Riverside, Riverside, CA, 92521, USA
| | - Marc-Etienne Moret
- Organic Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - W Hill Harman
- Department of Chemistry, University of California-Riverside, Riverside, CA, 92521, USA
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