Synthesis and characterization of dihydrobis(3,5-dimethylpyrazolyl)borate complexes of gallium(III) and indium(III)

Abstract

The reaction of MeGaCl 2 with one equivalent of K[H 2B(3,5-Me 2pz) 2] yields [H 2B(3,5-Me 2pz) 2]GaMeCl. The structure of [H 2B(3,5-Me 2pz) 2]GaMeCl has been determined crystallographically. The molecular unit is monomeric with a distorted tetrahedral geometry around gallium. The reaction of GaCl 3 with two equivalents of MeLi followed by one equivalent of K[H 2B(3,5-Me 2pz) 2] yields [H 2B(3,5-Me 2pz) 2]GaMe 2. Similar reactions starting with MeInCl 2 or Me 2InCl yield [H 2B(3,5-Me 2pz) 2]InMeCl and [H 2B(3,5-Me 2pz) 2]InMe 2, respectively. The reaction of MeInCl 2 with two requirements of K[H 2B(3,5-Me 2pz) 2] in refulxing THF yields [H 2B(3,5-Me 2pz) 2]InMe. In low-temperature NMr spectra of this complex (−40°C), each of the three types of hydrogen atom positions shows as two sharp, equally intense resonances. Each of the pairs of resonances coalesce at higher temperatures.