| Hydrogenases are enzymes mediators in hydrogen activation either for reduction or oxidation processes. There are three types of hydrogenase enzymes: (1) [Ni-Fe] hydrogenase. (2) [Fe-Fe] hydrogenase. (3) HMD or FeS cluster-free hydrogenases.;The first two are involved in producing hydrogen from H+ and electrons or evolving H2. HMD catalyzes the reduction of N 5,N10-methenyl-5,6,7,8-tetrahydro methanopterin, a hydrogen acceptor, and the reverse process. Hydrogenases possess iron moieties in their active centers; with carbonyl and cyanide ligands what is remarkable for being, so far, a singular case in biological systems.;A series of mimic complexes [(PS2')Fe(CN)x(CO)(3-x)] n (x= 0, 1, 2, 3) have been synthesized from the reaction of (PS2') 2- (bis(5-methyl-2-phenylthiolate) phenylphosphine) with FeCl2 in high yield. These compounds have been structurally characterized; their chemical, spectroscopic and electrochemical properties have been studied. They constitute useful spectroscopic models for the [Fe(CN) x(CO)y] centers in [Ni-Fe] and [Fe-Fe] hydrogenases and the cis-[Fe(CO)2] containing cofactor in Hmd hydrogenases.;Looking for a new synthetic route to achieve new mimics, a set of [Fe II,III(CN)4L2]n- complexes has been synthesized by the single step reaction of Fe(II) with CN-. This compounds have a moderate reactivity and are also useful building blocks to prepare new Prussian blue type materials and as possible stoichiometric or catalytic reagents.;The synthesis of the [Fe(CN)4L2] (L = monodentate ligand) and their applications is a new area in the chemistry of iron-cyanide compounds, the oldest known field of coordination chemistry. [FeII (CN)6]4-, the parent of iron-cyanide complexes, which has been known for 250 years is characterized by its inert nature such that it is not poisonous. [Et4N]4[FeII(CN) 6] is the first well characterized salt which is soluble in organic solvents. It is a powerful reducing agent and shows dramatic increases in the rate of substitution reactions of its CN- ligands. |
