Activation of Thiourea Bound through Sulfur to Pentaammineruthenium(III): Structure and Reactivity.

Abstract

An X-ray structure of (thiourea)pentaammineruthenium shows an sp3 sulfur atom bonded to Ru(III). Bond lengths and angles reveal substantial electronic reorganization in the thiourea with a significant contribution to the electronic structure from the resonance hybrid [(NH3)5Ru(-S−C(NH2+)NH2)]3+. Deprotonation (pKa 10.8) activates this polarized thiourea ligand to hydrolysis, oxidation, and formation of the diamagnetic dimer [((NH3)5RuIII−S−S−RuIII(NH3)5]4+. This may be another pathway to metal disulfide formation in biological systems.