Biomimics of [FeFe]-hydrogenases incorporating redox-active ligands: synthesis, redox properties and spectroelectrochemistry of diiron-dithiolate complexes with ferrocenyl-diphosphines as Fe₄S₄ surrogates

Abstract

[FeFe]-ase biomimics containing a redox-active ferrocenyl diphosphine have been prepared and their ability to reduce protons and oxidise H2 studied, including 1,1’-bis(diphenylphosphino)ferrocene (dppf) complexes Fe2(CO)4(-dppf)(-S(CH2)nS) (n = 2, edt; n...

Unsymmetric Co-Facial “Salixpyrrole” Hydrogen Evolution Catalysts: Two Metals are Better than One

“…Note that for 2 the monohydrate of p TSA was used for these measurements due to increased background overlap at higher acid concentrations when adding additional equivalents water (Figure S19). Although these values are not as large as the fastest reported HER catalysts from Bullock and co-workers, where TOFs over 100,000 s –1 were seen, − the salixpyrrole systems were still quite active, and compared favorably with known HER electrocatalysts from Artero, , Grapperhaus, − and many others. ,− It was also quite striking that 3 was almost three times faster than 2 , or alternatively, 40% faster on a per Pd atom basis. Moreover, under optimized conditions, 3 displayed a much lower overpotential than 2 ; 0.39 ± 0.2 vs 0.69 ± 0.4 V. Overpotentials were calculated using established procedures from Appel and Helm (see Supporting Information for sample overpotential calculations), as well as the experimentally determined p K a of p TSA in THF .…”

Facile access to tetra-substituted FeIIFeII biomimetics for the oxidized state active site of [FeFe]-hydrogenases

“…[11][12][13][14][15][16] Among these models, substitution of the basic [Fe 2 (μ-SR) 2 (CO) 6 ] core with various phosphines has been extensively studied due to their good electron-donating properties. [17][18][19][20][21][22][23][24][25][26][27][28][29][30] Multi-substituted Fe 2 (μ-SR) 2 (CO) 6−x P x (x ≥ 3) models were found to be highly reactive, [31][32][33][34][35][36] but they have not been studied extensively. With the increase in substitution degree, these models become more basic and easily protonated by acids.…”

Synthesis, Characterization and Electrochemical Studies of bis(Monothiolato) {FeFe} Complexes [Fe2(μ‐SC6H4‐OMe‐m)2(CO)5L] (L = CO, PCy3, PPh3)

“…Furthermore, most of the studies have considered mainly dithiolates as the linkers [1,19–50] . Only recently, the focus has shifted to monothiolate‐based {FeFe} systems.…”