Synthetic Active Site Model of the [NiFeSe] Hydrogenase

Synthetic Active Site Model of the [NiFeSe] Hydrogenase

A dinuclear synthetic model of the [NiFeSe] hydrogenase active site and a structural, spectroscopic and electrochemical analysis of this complex is reported. [NiFe('S2Se2')(CO)3] (H2'S2Se2' = 1,2-bis(2-thiabutyl-3,3-dimethyl-4-selenol)benzene) has been synthesized by reacting the nickel selenolate complex [Ni('S2Se2')] with [Fe(CO)3bda] (bda = benzylideneacetone). X-ray crystal structure analys...

Synthetic [FeFe] Hydrogenase Active Site Model Complexes

Oxidative inactivation of NiFeSe hydrogenase.

We propose a resolution to the paradox that spectroscopic studies of NiFeSe hydrogenase have not revealed any major signal attributable to Ni(III) states formed upon reaction with O2, despite the fact that two inactive states are formed upon either aerobic or anaerobic oxidation.

Evidence for selenocysteine coordination to the active site nickel in the [NiFeSe]hydrogenases from Desulfovibrio baculatus.

Ni and Se x-ray absorption spectroscopic studies of the [NiFeSe]hydrogenases from Desulfovibrio baculatus are described. The Ni site geometry is pseudo-octahedral with a coordinating ligand composition of 3-4 (N,O) at 2.06 A, 1-2 (S,Cl) at 2.17 A, and 1 Se at 2.44 A. The Se coordination environment consists of 1 C at 2.0 A and a heavy scatterer M (M = Ni or Fe) at approximately 2.4 A. These res...

Bio-inspired, side-on attachment of a ruthenium photosensitizer to an iron hydrogenase active site model.

The first ruthenium-diiron complex [(mu-pdt)Fe2(CO)5{PPh2(C6H4CCbpy)}Ru(bpy)2]2+ 1 (pdt = propyldithiolate, bpy = 2,2'-bipyridine) is described in which the photoactive ruthenium trisbipyridyl unit is linked to a model of the iron hydrogenase active site by a ligand directly attached to one of the iron centers. Electrochemical and photophysical studies show that the light-induced MLCT excited s...