H₂ Activation in [FeFe]‐Hydrogenase Cofactor Versus Diiron Dithiolate Models: Factors Underlying the Catalytic Success of Nature and Implications for an Improved Biomimicry

Abstract

CatalyticH 2 oxidation has been dissected by means of DFT into the key steps commont ot he Fe 2 unit of both the [FeFe]-hydrogenase cofactor and selected biomimics. The aim wast oe lucidate the moleculard etails underlying the very different performances of the two systems.

Rational Design of Fe2(μ‐PR2)2(L)6 Coordination Compounds Featuring Tailored Potential Inversion

“…The present DFT calculations, carried out by means of the TURBOMOLE 7.2 suite, [50] explore different exchange and correlation functionals, in order to corroborate the energy trends that emerge comparing the calculated potentials for the different Fe 2 P 2 complexes. Given the similarity of these systems to classic hydrogenase models, we chose the BP86 functional, [51,52] which has been extensively used and validated for that class of compounds, [53][54][55][56] adding Grimme correction for dispersive contributions (BP86-D3). [57] Structures were also optimized using the B97-D functional (B97 re-parameterized to account for dispersions) [58] and, additionally, some molecules belonging to the set were optimized using the M06 functional (results not shown).…”

Insights into the Two‐Electron Reductive Process of [FeFe]H2ase Biomimetics: Cyclic Voltammetry and DFT Investigation on Chelate Control of Redox Properties of [Fe2(CO)4(κ2‐Chelate)(μ‐Dithiolate)]

“…All calculations were performed with the pure functional BP86 [28, 29] (as implemented in the TURBOMOLE 7.2 program package), [30] in conjunction with TZVP basis set (triple‐ξ for valence electrons plus polarization function) [31] . This Scheme is rather popular in the theoretical investigation of diiron complexes related to [FeFe]‐hydrogenases [32–34] . The D3 correction method and the COSMO approach were used to account for dispersive and solvent (MeCN, ϵ =37.5) effects, respectively [35, 36] .…”

“…[31] This Scheme is rather popular in the theoretical investigation of diiron complexes related to [FeFe]-hydrogenases. [32][33][34] The D3 correction method and the COSMO approach were used to account for dispersive and solvent (MeCN, e = 37.5) effects, respectively. [35,36] The nature of each stationary point was determined by full vibrational analysis, which was also used to make zero-point and thermal corrections to electronic energies to obtain free energy values.…”

Successes, challenges, and opportunities for quantum chemistry in understanding metalloenzymes for solar fuels research

“…Disclosure of these differences will guide the development of novel biomimetic models and lead to reconsider the utility of CN ligand in the catalyst design. 336 In addition to the extensive use of DFT methods, QM/MM thermodynamic cycle perturbation (QTCP) computations were recently shown as a valuable approach to obtain accurate free energies to model the catalytic cycle for hydrogen evolution by hydrogenases. In these calculations, the QM/MM method is used to compute the energy differences on configurations generated by MD simulations.…”