Solvothermal Synthesis And Characterization Of Novel Quaternary Chalcogenides In Chelating Agent

Chalcogenides possess very diverse and interesting structures and exhibit useful physical and chemical properties which have many applications in modern technologies. In recent years, the synthesis of binary and ternary chalcogenides has been extensively investigated by the method of high-temperature solid state, intermediate-temperature flux and low-temperature solvothermal techniques. Comparing with them, the synthesis of quaternary chalcogenides is limited and its synthesis is becoming an active area of solid state chemistry. Up to now, most known quaternary chalcogenides are prepared by the molten alkali-metal polychacogenide flux technique and low-temperature solvo- (hydro)thermal reactions have developed a limited number of quaternary chalcogenides. As metal chalcogenide framework materials can be prepared at the presence of inorganic and organic cations as directing agent in solution, the mild solvothermal technique is especially suitable for synthesis of new solids. Main group metal thio-anionic clusters are often found to serve as structure building units in these metal-chalcogenides open-framework materials; these clusters usually go through self-condensation or are connected by transition metal ions in solution to form frameworks. Because of less soluble transition metal, it prefers to form chalcogenides by the solution route, but it is usually difficult to synthesize and obtain pure phases of these compounds. Therefore the number of known synthetic quaternary chalcogenides is surprisingly small. We believe that chelating agent can counteract the formation of the less soluble transition metal sulfide in the solvothermal synthesis.In order to synthesize new quaternary chalcogenides, we have developed a new mild synthetic route. In this thesis, we designed the synthesis method of three series of novel quaternary sulfides (containing silver ion), which used 2,3-dimercapto-propanol as chelating agents and pyridine or ethanol as solvent, and summarized their synthesis and structure chemistry regularity.1. Synthesis of A-Ag-Sn-S (A=K⁺, [NH₄]⁺, [NH₃CH₂CH₂NH₃]²⁺) series of compoundsA novel layered K₄Ag₂Sn₃S₉·2H₂O(1) was synthesized solvothermally and characterized by X-ray single-crystal diffraction. The compound crystallizes in the monoclinic, P2₁/m space group, α=7.8071(2)A, b=27.3508(1)A, c=10.5008(2)A, β=103.874(1)°, Z=A. The layer comprises [AgSn₃S₉]^5- clusters linked by Ag⁺ ions and possesses two types of 1D channels in which potassium ions are located. A novel framework K₂Ag₆Sn₃S₁₀(2) was synthesized...