Zur Reaktion aromatischer Phosphanderivate mit Elektronen, III [1, 2] Phosphan-Borane, -Alane und -Gallane / On the Reaction of Aromatic Phosphane Derivatives with Electrons, III [1, 2] Phosphane-Boranes, -Alanes, and -Gallanes

Abstract

The 1:2 molecular complexes formed from 1,4-phenylenebis(dimethylphosphane) and boranes, trialkyl-aluminum and -gallium have been reduced by potassium in THF in the presence of a K+ - complexing crown ether. The bis(borane) complex anion radicals proved to be quite persistent, whereas corresponding aluminum radical complexes could only be observed below 240 K. The bis(trimethylgallium) complex gave gallium metal on reduction with potassium. An ESR spectroscopic comparison with the anion radicals of the free ligand, of corresponding chalcogenides, imines and phosphonium salts demonstrates negligible effects of P-complexation on the π spin distribution but high sensitivity of the 31P coupling constant towards coordination of electrophiles at the basic P(III) centers