Among the large family of mononuclear bis-diphosphine nickel catalysts with pendant amines, the so-called NiCyArg complex, with a cyclohexyl group at the phosphine and an arginine substituted amine, h...

The expression “catalytic reversibility” describes the situation where a bidirectional molecular redox catalyst can function in either direction of the reaction under near equilibrium conditions, as o...

[FeFe] hydrogenases are highly efficient metalloenzymes that catalyze hydrogen conversion via a sophisticated active site cofactor known as the H-cluster. Biosynthesis of its [2Fe]H subcluster, which ...

Enzymatic biofuel cells (EBFCs) utilizing hydrogenases to oxidize hydrogen offer a sustainable approach to energy conservation. However, the oxygen se…

Herein, we show for the first time that thiolate ligands can play an important role in promoting 2e- oxo atom transfer with nonheme iron. We examine the mechanism of oxo atom transfer to a cis thiolate sulfur for two structurally related iron complexes using low-temperature kinetics, spectroscopic, and computational methods. Intermediate oxo atom donor adducts, FeOIAr, are spectroscopically characterized and shown to have electronic spectral, EPR, and Mössbauer parameters, and kinetic barriers dependent on the nature of the oxo atom donor. More stable adducts containing pyridine N-oxide (PNO) were crystallographically characterized and computationally optimized to establish optimum functionals and basis sets. Oxo atom transfer is shown both experimentally and computationally to involve a stepwise, as opposed to a concerted, mechanism. A new metastable intermediate is observed by low-temperature Mössbauer and ⊥-mode EPR after the Fe–OxIPh intermediate and prior to the final sulfenate Fe-OSR product. The DFT calculated minimum energy pathway is shown to contain a local minimum between the Fe–O2IPh adduct and Fe–S(R)O product. The DFT optimized geometric and electronic structure of this intermediate is shown to be consistent with an S = 1 Fe(IV)═O that is antiferromagnetically coupled to an S = 1/2 radical delocalized over the two cis thiolate-sulfurs, analogous to the electronic configuration of P450 Cmpd I. Radical character on the thiolate sulfur adjacent to the oxo is shown to facilitate trapping of the high-valent Fe-oxo as a η2-SO-Fe sulfenate complex.

Manganese bipyridine tricarbonyl complexes show high efficiency and selectivity in electrochemical CO2 reduction (e-CO2RR) to CO. Efforts to shift selectivity toward HCOOH have been made by introducin...

Heme nitrite reductases (NiRs) are key enzymes in the assimilatory and dissimilatory reduction of nitrite (NO2–) by 6e–/8H+ to NH4+ and by 1e–/2H+ to NO during denitrification in the global nitrogen c...

Developing efficient photocatalytic systems for sustainable H2 production is a crucial step toward reducing dependence on fossil fuels. While extensive research over the past two decades has focused o...