Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF2)2 and Co(dmgH)2 Cobaloxime Complexes in Acetonitrile–Water Solvent

Chen, Jinfan; Sit, Patrick H.‐L.

doi:10.1021/acs.jpca.7b00163

Cited by 15 publications

(34 citation statements)

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“…229,230 Similar reactions involving proton transfer on biomimetic catalytic complexes and materials have been reported, such as hydrogenase model complexes, 231 hydrogen production from water promoted by a hydrogenase-inspired catalyst [FeFe]/electrode complex [FeS 2 ], 232 or cobaloxime catalysts. 233…”

Section: Competition Between Methods and Model Accuracies In Computatimentioning

confidence: 99%

Computational Approach to Molecular Catalysis by 3d Transition Metals: Challenges and Opportunities

et al. 2018

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Computational chemistry provides a versatile toolbox for studying mechanistic details of catalytic reactions and holds promise to deliver practical strategies to enable the rational in silico catalyst design. The versatile reactivity and nontrivial electronic structure effects, common for systems based on 3d transition metals, introduce additional complexity that may represent a particular challenge to the standard computational strategies. In this review, we discuss the challenges and capabilities of modern electronic structure methods for studying the reaction mechanisms promoted by 3d transition metal molecular catalysts. Particular focus will be placed on the ways of addressing the multiconfigurational problem in electronic structure calculations and the role of expert bias in the practical utilization of the available methods. The development of density functionals designed to address transition metals is also discussed. Special emphasis is placed on the methods that account for solvation effects and the multicomponent nature of practical catalytic systems. This is followed by an overview of recent computational studies addressing the mechanistic complexity of catalytic processes by molecular catalysts based on 3d metals. Cases that involve noninnocent ligands, multicomponent reaction systems, metal–ligand and metal–metal cooperativity, as well as modeling complex catalytic systems such as metal–organic frameworks are presented. Conventionally, computational studies on catalytic mechanisms are heavily dependent on the chemical intuition and expert input of the researcher. Recent developments in advanced automated methods for reaction path analysis hold promise for eliminating such human-bias from computational catalysis studies. A brief overview of these approaches is presented in the final section of the review. The paper is closed with general concluding remarks.

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Section: Competition Between Methods and Model Accuracies In Computatimentioning

confidence: 99%

Computational Approach to Molecular Catalysis by 3d Transition Metals: Challenges and Opportunities

et al. 2018

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“…The hydrogen production reaction pathways found in the localized basis set DFT calculations in this work are in agreement with those found in the plane-wave DFT calculations. 18…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, the easy dissociation of the axial ligand from the complexes makes these two complexes the same at the end of the reaction. 18,53…”

Section: Resultsmentioning

confidence: 99%

“…These coordination configurations were previously found to be favorable in each case. 18 For Co(dmgH) 2 (py)(Cl), the Cl – was found to readily dissociate from the complex and be replaced by a H 2 O molecule in the aqueous environment after being reduced. 53 Therefore, Co(dmgH) 2 (py)(Cl) was replaced by Co(dmgH) 2 (py)(H 2 O) when solvated in the AN–water mixture.…”

Section: Dft Approaches For the Calculation Of Reduction Potentials mentioning

confidence: 98%

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Thermodynamic Properties of Hydrogen-Producing Cobaloxime Catalysts: A Density Functional Theory Analysis

Chen

Sit

2019

ACS Omega

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Density functional theory calculations were carried out to study the electrochemical properties including reduction potentials, p K a values, and thermodynamic hydricities of three prototypical cobaloxime complexes, Co(dmgBF 2 ) 2 (dmgBF 2 = difluoroboryl-dimethylglyoxime), Co(dmgH) 2 (dmgH = dimethylglyoxime), and Co(dmgH) 2 (py)(Cl) (py = pyridine) in the acetonitrile (AN)–water solvent mixture. The electrochemical properties of Co(dmgBF 2 ) 2 in pure AN and pure water were also considered for comparison to reveal the key roles of the solvent on the catalytic reaction. In agreement with previous studies, hydrogen production pathways starting from reduction of the resting state of Co II and involving formation of the Co III H and Co II H intermediates are the favorable ones for both bimetallic and monometallic pathways. However, we found that in pure AN, both the Co III H and Co II H intermediates can react with a proton to produce H 2 . In the presence of water in the solvent, the reduction of Co III H to Co II H is necessary for the reaction with a proton to occur to form H 2 . This suggests that it is possible to design catalytic systems by suitably tuning the composition of the AN–water mixture. We also identified the key role of axial coordination of the solvent molecules in affecting the catalytic reaction, which allows further catalyst design strategy. The highest hydride donor ability of Co(dmgH) 2 (py)(Cl) indicates that this complex displays the best catalytic hydrogen-producing performance among the three cobaloximes studied in this work.

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“…A los efectos de comprender mejor el mecanismo de la producción catalítica de hidrógeno catalizada por cobaloximas, se han venido realizando estudios de química computacional utilizando la teoría del funcional de la densidad (DFT por sus siglas en inglés) (Chen & Sit, 2019;Chen & Sit, 2017).…”

Section: Dimetilglioxima En Síntesis Orgánica Y Catálisisunclassified

DIMETILGLIOXIMA: un reactivo químico con 100 años de historia

et al. 2019

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La dimetilglioxima (diacetildioxima o butano-2,3-dioxima), dmgH2, es uno de los quelatos de uso más extendido en química de coordinación y analítica. La reacción de formación del bis(dimetilglioximato) de níquel(II), reportada por Lev A. Chugaev (Tschugaeff) en 1905, constituye una de las primeras pruebas específicas para la identificación cualitativa de un metal de transición. Desde entonces, y por más de un siglo, la dimetilglioxima adquirió importancia como un notable agente quelante, y sus compuestos complejos se han venido utilizando en áreas como la química inorgánica, catálisis, electroquímica, ciencia de materiales, entre otras. En este artículo, presentamos una breve revisión de la dimetilglioxima, los dimetilglioximatos metálicos y algunas de sus aplicaciones más representativas. La revisión indica que, además de su gran éxito como reactivo analítico para la determinación de metales, existen importantes estudios de los dimetilglioximatos metálicos como catalizadores de diversas reacciones, destacando la producción de hidrógeno molecular, una reacción de importancia por su impacto en la economía del hidrógeno y la química verde.

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Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF₂)₂ and Co(dmgH)₂ Cobaloxime Complexes in Acetonitrile–Water Solvent

Cited by 15 publications

References 76 publications

Computational Approach to Molecular Catalysis by 3d Transition Metals: Challenges and Opportunities

Computational Approach to Molecular Catalysis by 3d Transition Metals: Challenges and Opportunities

Thermodynamic Properties of Hydrogen-Producing Cobaloxime Catalysts: A Density Functional Theory Analysis

DIMETILGLIOXIMA: un reactivo químico con 100 años de historia

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