Faizah S Aljohani
Taibah University, Saudi Arabia
Title: Hydrogen bonding interactions of tris and bis urea and thioureas with cyanide ligand in an analogue of the sub-site of [FeFe]-hydrogenase
Biography
Biography: Faizah S Aljohani
Abstract
Second coordination sphere interactions of metal centres involving hydrogen bonding, ion-pairing or dipolar bonding can play an important role in determining the physical and chemical properties of molecular and biomolecular systems. The second coordination sphere interactions of coordinated cyanide in a model for the diiron subsite of [FeFe]-hydrogenase has been examined. The natural subsite in its protein environment catalyses hydrogen evolution (or uptake) at very fast rates ca 104 s-1 near the reversible potential of the H+ 1/2 H2 couple but such rates have yet to be attained in model systems. Controlling the electronic and geometric properties of synthetic diiron subsites by hydrogen bonding or other interactions might provide a means of attaining the turnover rates of the natural system. The specific approach taken in this work was to explore the potential binding properties of certain bis- and tris-(thio)ureas to the synthetic subsite analogue [Fe2(CO)4(CN)2pdt]2-. It is shown that hydrogen bonding interactions with the ligated cyanide using certain activated amides also perturbs spectroscopic and redox properties and importantly, the rate of protonation at the metal-metal bond and the stability of the resulting µ-hydride.