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

The bis-1,4-dioxane (diox) adduct of bromomethyl-dibromo-indium(III), Br2In (diox)(2)CH2Br, reacts with triphenylphosphine oxide, triphenylphosphine su lfide and benzyl sulfide to produce the compounds Br2In[OP(C6H5)(3)](2)CH2B r and Br3InCH2L (L = benzyl sulfide, triphenylphosphine sulfide). The cryst al structures of these new organoindium compounds have been solved by X-ray diffraction methods. The structural results are compared with those for re lated organoindium compounds. Quantum mechanical calculations, by the PM3 m ethod, satisfactorily predict the measured bond distances and angles in all compounds, and hence furnish reliable net atomic charge maps, which demons trate the presence of a sulfur ylid ligand, H2Cdelta--Sdelta+(CH2C6H5)(2), and a triphenylphosphonium-sulfur methylide ligand, delta-CH2S-Pdelta+(C6H5 )(3), in the Br3InCH2L compounds. Mass spectra and thermal decomposition st udies establish that Br3InCH2S(CH2C6H5)(2) decomposes via an intramolecular nucleophilic attack of a bromide ligand, either to the InCH2 carbon atom t o produce benzyl sulfide, or to the C,H,CH? carbon to yield benzyl bromide and benzyl-methyl-sulfide. (C) 2001 Elsevier Science B.V. All rights reserv ed.