Benzenoid-quinoid tautomerism of azomethines and their structrual analogues XXX. Molecular structure of gallium and boron organometalic compounds with tautomeric azomethines

Abstract

The electronic structure and conformations of a systematic series of dimethylgallium and diphenylboron derivatives of aromatic and heterocyclic hydroxy- and mercaptoazomethines have been studied using the methods of electron absorption and emission spectroscopy and dipole moments. Although their phenyl- and methylmercury analogues tend to undergo tautomeric transformations, organometallic compounds of gallium and boron have in solution a mesomeric intra-complex structure with tetracoordinated gallium and boron. The molecular structure of two gallium chelates, dimethylgallium N-methylsalicylaldiminate and 2-( N-phenylaminomethylene)-3(2H)-benzo(b)furanthionate, have been determined by X-ray diffraction analysis. Structural parameters indicate that chelate formation causes a considerable redistribution of bond lengths in the ligand.