Syntheses and structures of [M{In(SC{O}Ph)4}2] (M = Mg and Ca):: Single molecular precursors to MIn2S4 materials

The compounds [Mg{In(SC{O}Ph)(4)}(2)] (1) and [Ca(H2O)x{In(SC{O}Ph)(4)}(2)]center dot yH(2)O (x = 0, y = 1, 2 major product; x = 1, y = 0, 2a minor product; x = 2, y = 2, 2b minor product) have been synthesized by reacting InCl3 and M(SC{O}Ph)(2) (M = Mg and Ca) prepared in situ in the molar ratio 1:2. The structures of 1, 2a, and 2b have been determined by X-ray crystallography. The structure of 1 consists of two tetrahedral [In(SC{O}Ph)(4)](-) anions sandwiching the MgII metal ions through six carbonyl O atoms. The coordination geometry at the MgII metal atom is distorted octahedral with an O-6 donor set. The structures of 2a and 2b consist of two [In(SC{O}Ph)(4)](-) anions sandwiching the Ca-II metal ion through five and four carbonyl O atoms, and the octahedral coordination at the CaII centers is completed by one and two aqua ligands, respectively. Two aqua ligands and two lattice water molecules form a H-bonded water chain in the channel created by [Ca{In(SC{O}Ph)(4)}(2)] molecules in the crystal structure of 2b. The thermal decomposition of 1 and 2 indicated the formation of the corresponding MIn2S4 materials, and this was confirmed by X-ray powder diffraction patterns.