In(SPh)3 is readily prepared by the reaction of InCl3 and NaSPh in methanol. The compound is a Lewis acid, forming 1:1 adducts with 2,2′-bipyridine, 1,10-phenanthroline, N,N,N′,N′-tetramethylethanediamine, bis(diphenylphosphino)ethane, and dimethylsulphoxide, and 1:2 adducts with pyridine, trimethylamine, and triphenylphosphine. Reaction with R4NX (X = Cl, Br, I) or similar salts gives R4N[XIn(SPh)3] salts, which are 1:1 electrolytes. The structure of Ph4P[BrIn(SPh)3] has been determined by X-ray methods. The crystals are monoclinic, space group P21/c, with cell dimensions a = 9.964(3) Å, b = 13.477(3) Å, c = 30.359(7) Å, α = 98.30(2)°, Z = 4, R = 0.0622 for 2924 unique observed reflections. The anion has distorted tetrahedral symmetry in the InBrS3 kernel, with In—Br = 2.527(2) Å, and In—S(av) = 2.450 Å. The vibrational spectra of In(SPh)3 and its derivatives in the region 500–200 cm−1 are discussed.
