REACTIONS OF HALOGENOMETHYL COMPLEXES OF INDIUM, X2INCH2X (X = BR, I), WITH 1,1,3,3-TETRAMETHYL-2-THIOUREA

Indium(I) halides, InX, react with methylene dihalides CH2X2 (X = Br, I) to give X2InCH2X derivatives. The bromide compound reacts with 1,1, 3,3-tetramethyl-2-thiourea (tmtu) to give the thiouronium derivative B r3InCH2SC[N(CH3)2]2, whose molecular structure has been established by X-ray crystallography: cell constants a = 12.05(2) angstrom, b = 16.0 2(1) angstrom, c = 7.411(3) angstrom; space group P2(1)2(1)2(1), R = 0 .056, R(w) = 0.053. The corresponding reaction with the iodide analogu e yields the ionic species [H2C{SC[N(CH3)2]2}2]2+ (InI4-)2 whose struc ture has also been identified: cell constants a = 10.468(2) angstrom, b = 23.081(4) angstrom, c = 15.317(2) angstrom, beta = 102.14(2)-degre es; space group P2(1)/n, R = 0.059, R(w) = 0.070. The formation of the thiouronium complex confirms that the CH2 group in X2InCH2X is electr on-poor, in keeping with the tendency for nucleophilic ligands to reac t at this site.