Ethylene polyamine influence on the transition metal thiogermanates: Solvothermal syntheses and characterizations of [Ni(trien)2]2Ge4S10 and [{Ni(tepa)}2(μ-Ge2S6)

Abstract

Novel nickle thiogermanates [Ni(trien)2]2Ge4S10 (1) (trien = triethylenetetramine) and [{Ni(tepa)}2(μ-Ge2S6)] (2) (tepa = tetraethylenepentamine) were respectively synthesized by the reaction of NiCl2·6H2O, GeO2 and S in trien and tepa under solvothermal conditions. The adamantane-like [Ge4S10]4− anion in 1 is composed of four GeS4 tetrahedra sharing the corners with three other tetrahedra via S2− bridges. 1 is the first example of damantane-like [Ge4S10]4− anion with transition metal complex as the counter cation. The bimeric [Ge2S6]4− anion in 2 is constructed by two GeS4 tetrahedra sharing a common edge. It acts as a μ-Ge2S6 ligand with the trans terminal S atoms to connect two [Ni(tepa)]2+ cations into the neutral complex 2. The syntheses of 1 and 2 show the influence of different ethylene polyamines on the formation of thiogermanates in the presence of transition metal. 1 and 2 exhibit semiconducting properties with the band gap Eg at 2.31 and 2.48 eV respectively.