Solvothcrmal Synthesis And Crystal Structure Of Novel Muitinary Chalcogenidogermanates And Chalcogenidostannates

Multinary chalcogenides possess diverse physical and chemicalproperties. Due to their potential applications in various technological areassuch as semiconductor, nonlinear optics, visible-light photocatalysis, andphotoluminescence, multinary chalcogenides are becoming more popular infield of new functional materials. Nowadays, most of multinary chalcogenidesare obtained by high-temperature solid state technique. Because of the hightemperature reaction conditions will lead to some of the conventional bond bebroken, the chalcogenides, which prepared by solid state method, are usuallythermodynamically stable phase. As for solvothermal synthesis, due to itsmild reaction conditions, some components that unstable at high temperature,can integrate into the final products and we can get the compounds of themetastable or intermediate state. To carrying out the solvohermal synthesis ofmultinary chalcogenides, it can not only rich the structural chemistry ofchalcogenides, but also broaden the existing synthetic methods ofchalcogenides. Using alkali metal cations or organic amines asstructure-directing agents, a series of chalcogenidogermanates andchalcogenidostannaes were synthesized, and their structure andsemiconductor properties are discussed.1. Using alkali metal cations K⁺and Rb⁺as the charge balancing ionsand using1,2-ethanedithiol as chelating agent, in the solvothermal conditionof pyridine, two new multinary chalcogenidogermanates（H₃O）₁₀A₆Cu₃₂Ge₁₂S₄₈·6H₂O（A=K, Rb）（1，2）were synthesized. Thesecompounds crystallized in the cubic system, space group Fm3c. Compounds1and2are isostructural and both of them contain icosahedral [Cu₈S₁₂]^16-anionic clusters. These clusters are linked by [GeS₄]^4- to form a3D openframework and generate3D channels. The optical band gaps of the two compounds are4.6and5.0eV, respectively.2. Using1,2-propanediamine as structure-directing agent, a novelselenium germanates （1,2-dapH₂）_0.5Cu_2.67GeSe_5.17（3） was synthesizedsolvothermally. This compound crystallizes in the cubic system, space groupPa3. The structure of this compound is novel and unique, it contains unusualanionic clusters [Cu₄Se₆]^4-and [GeSe45]-as its main structural units. The[Cu₄Se₆]^4-anions are constructed by four corner-sharing [CuSe3] units, andeach of them is connect to other three [Cu₄Se₆]^4-anions by three [GeSe₅]^4- toform a3D open framework and generate two different channels, thisphenomenon is very rare in multinary chalcogenides.3. Ba-Cu-Ge-S crystals are obtained successfully in the1,2-ethanedithiol/pyridine solvothermal condition, and the possible formula ofthem is BaCu₂GeS₄in accordance with their EDS analysis results, and singlecrystal structure analysis of the compound is in progress. Currently, the mainway to get multinary chalcogenides containing barium is solid state technique,and only a limited number of them are prepared by soft chemical method. Thesolvothermal synthetic research of compound4has great sinificance ondeveloping soft chemical synthetic mehod of multinary chalcogenidecontaining barium s.4. Using alkali metal carbonate as mineralizer, a quaternary chalcogenidostannate Rb₂HgSnS₄（5）were obtained in1,2-ethanedithiol/pyridine （volumnratio1:2） solvothermal condition. This compound crystallizes in themonoclinic system, space group C₂/c. Compound5was consisted ofadamantane-like anionic clusters [Hg8-2Sn2S10]as its building block. Thestructure of [Hg₂Sn₂S₁₀]^8-contains two crystallographic independent T（T=Hgor Sn） atoms. T1and T2atoms are both coordinated by four S atoms. A pairof T1S₄tetrahedra and a pair of T2S₄tetrahedra are condensed into anadamantine-like cluster [Hg₂Sn₂S₁₀]^8-via corner-sharing. Eachadamantine-like cluster [Hg₂Sn₂S₁₀]^8-connect other four adamantine-likecluster [Hg₂Sn₂S₁₀]^8-through four S4atoms to construct a sheet. The result ofUV-Vis reflectance spectroscopy of this compound shows that it is a semiconductor material.