No abstract

Two new heterodinuclear nickel-iron complexes [Ni(pbSmSe)FeCpCO]PF and [Ni(xbSmSe)FeCpCO]PF were synthesized as mimics of the [NiFeSe] hydrogenase active site (HCp = cyclopentadiene; HpbSmSe = 1,9-diselenol-3,7-dithia-2,2,8,8-tetramethylnonane; HxbSmSe = 1,2,-bis(2-thiabutyl-3,3-dimethyl-4-selenol)benzene). The compounds were characterized by single crystal X-ray diffraction and cyclic voltammetry. X-ray structure determinations showed that in both NiFe complexes the nickel(ii) center is in a square-planar SSe environment; the two selenolate donors are bridging to the iron(ii) center that is further coordinated to an η-cyclopentadienyl group and a carbon monoxide ligand. Electrochemical studies showed that the complex [Ni(pbSmSe)FeCpCO]PF is an electrocatalyst for the production of H in DMF in the presence of acetic acid at -2.1 V vs. Fc/Fc; a foot-of-the-wave (FOWA) analysis of the catalytic currents yielded an estimation of k of 24 s.

xbSmS = 1,2-bis(4-mercapto-3,3-dimethyl-2-thiabutyl)benzene; H 2 xbSmSe = 1,2-bis(2-thiabutyl-3,3-dimethyl-4-selenol)benzene; phen = phenanthroline]. The two [Ni 2 Ru] complexes were characterized by ESI-MS, NMR spectroscopy, elemental analysis, single-crystal X-ray crys-