X-RAY CRYSTAL-STRUCTURE OF INCL32THF, A NEUTRAL 5-COORDINATE BIS-ADDUCT OF AN INDIUM(III) TRIHALIDE

The 2:1 mole ratio reaction of InCl3 and P(SiMe3)3 in a toluene/THF mixture was investigated. The reaction appears to occur in a 1:1 mole fashion, since the products obtained are unreacted InCl 3 (48.5 % recovered) as InCl3.2THF and a fine powder which appears to be [Cl2In3P3(SiMe3)2]n. The latter was characterized by melting point and partial elemental analysis. The X-ray crystal structure of InCl 3.2THF shows it to be a neutral penta-coordinated bis-adduct of an indium(III) trihalide. The crystal structure consists of discrete monomeric units with no abnormally short intermolecular separations. The geometry about the indium atom approximates to trigonal bipyramidal with oxygen atoms of each of the THF molecules occupying axial positions [In-O = 2.257(9) angstrom, O-In-O = 178.5(3)-degrees], while the three chlorine atoms (mean In-Cl = 2.321 angstrom) lie in the equatorial plane.