Monocations of bismuth and indium in arene media: A spectroscopic and EXAFS investigation

The composition of In-GaCl3-benzene and In-BiCl3-GaCl3-benzene solutions wa s investigated by Raman, UV/Vis, Ga-71 and In-115 NMR spectroscopy as well as by X-ray absorption fine structure spectroscopy (EXAFS). Indium metal wa s found to be soluble in GaCl3-benzene solution at room temperature through the reduction of Ga-III, producing Ga+ and In+ species. The subvalent cati ons are likely to be stabilized by the interaction with benzene. The use of these solutions as reducing media for BiCl3 leads to the formation of Bi-5 (3+) polycations, with Bi+ as an intermediate product. No other subvalent b ismuth species were detected. Multinuclear NMR experiments show that the re ducing agent is Ga+ rather than In+. Indium K-edge EXAFS data recorded from solutions without and with subvalent bismuth species present show that In is co-ordinated by benzene (at about 2.9 Angstrom) and chlorine atoms from chlorometalate anions (at about 3.3 Angstrom) in a formal ratio of 1:2. El ectrospray mass spectroscopic data show that In+ is most likely co-ordinate d by one arene molecule.