Preparation, crystal structure determination, and properties of adducts of halogenomethyl compounds of indium with Group 16 donors

The bis-1,4-dioxane (diox) adduct of bromomethyl-dibromo-indium(III), Br2In(diox)2CH2Br, reacts with triphenylphosphine oxide, triphenylphosphine sulfide and benzyl sulfide to produce the compounds Br2In[OP(C6H5)3]2CH2Br and Br3InCH2L (L=benzyl sulfide, triphenylphosphine sulfide). The crystal structures of these new organoindium compounds have been solved by X-ray diffraction methods. The structural results are compared with those for related organoindium compounds. Quantum mechanical calculations, by the PM3 method, satisfactorily predict the measured bond distances and angles in all compounds, and hence furnish reliable net atomic charge maps, which demonstrate the presence of a sulfur ylid ligand, H2Cδ−δ+S(CH2C6H5)2, and a triphenylphosphonium-sulfur methylide ligand, δ−CH2Sδ+P(C6H5)3, in the Br3InCH2L compounds. Mass spectra and thermal decomposition studies establish that Br3InCH2S(CH2C6H5)2 decomposes via an intramolecular nucleophilic attack of a bromide ligand, either to the InCH2 carbon atom to produce benzyl sulfide, or to the C6H5CH2 carbon to yield benzyl bromide and benzyl-methyl-sulfide.