Hydrazine-Assisted Syntheses and Properties of Mercury Tellurides Containing Transition-Metal Complexes.

With assistance of reactive and coordinative hydrazine, transition-metal telluromercurates [Mn(trien)(N2H4)2]2[Hg2Te4]2 (A), [Zn(trien)(N2H4)2]Hg2Te4 (B), [Mn(tepa)(N2H4)]2Hg4Te12 (C), [TM(trien)(Hg2Te4)] (TM = Mn (D), Zn (E)), and [Zn(atep)]2Hg5Te12 (atep = 4-(2-aminoethyl)triethylenetetramine) (F) were solvothermally prepared in triethylenetetramine (trien) or tetraethylenepentamine (tepa) solvents using elemental Te as precursor in lower temperature range. Compounds A and B consist of mixed coordination cations [TM(trien)(N2H4)2]2+ (TM = Mn, Zn) and one-dimensional polyanion [Hg2Te4]2- with the five-membered Hg2Te3 rings being coplanar. Compound C is composed of two [Mn(tepa)(N2H4)]2+ cations and a [Hg4Te12]4- cluster with a centrosymmetric structure. Compounds D and E consist of coordination polymer [TM(trien) (Hg2Te4)] containing novel doubled [Hg2Te4]n chain with tetrahedrally coordinated Hg(II) centers, which is quite different from the common single chain with the same composition of [Hg2Te4]n. D and E are the first examples of telluromercurates incorporated with TM complex units via TM-Te bonds. Compound F contains fivefold coordinated [Zn(atep)]2+ cations and zigzag [Hg5Te124-]n polymeric anion. The [Hg5Te124-]n anion is a new species of the binary telluromercurates. It is built from [Hg4Te6] and [HgTe2(Te4)] subunits via interconnectivity, which generates Hg3Te3 and Hg4Te4 rings in the structure. Compounds A-F are potential semiconductors with narrow band gaps in the range of 0.96-1.09 eV. Photocatalytic investigation of Mn(II) complexes show that they are photocatalytically active in the degradation of CV under visible-light irradiation with the highest catalytic effective of cluster compound C.