Dithiocarbamato chelated chloro bridged linear trinuclear rhenium complexes: Synthesis, structure, spectroscopic and computational studies

Abstract

Quadruply bonded dirhenium(III) complex (Bu4N)2[Re2Cl8] (1) reacts with sodium salts of dimethyldithiocarbamate, diethyldithiocarbamate and pyrrolidinedithiocarbamate in ethanol under stirring condition to afford the dithiocarbamato chelated chloro bridged linear trinuclear rhenium complexes of the type [Re3(μ-Cl)2(η2-LR)6(OH2)2][ReO4] (2(LR)) where LR represents the dithiocarbamato ligands [LR = S2CNMe2, 2(LMe); S2CNEt2, 2(LEt) and S2CN(CH2)4, 2(LPyr)]. These are the first examples of rhenium complexes in which the novel linear [Re–Cl–Re–Cl–Re] unit is present. These complexes have very similar spectral and electrochemical properties which are also reported. Structural identity of the complex 2(LEt) has been established by X-ray crystal structure determination. Density functional theory calculation shows that for 2(LEt), both the HOMO and LUMO are mainly composed of rhenium d-orbitals and LEt ligands p orbitals.