X-RAY-INVESTIGATION OF ELECTRON-DENSITY REDISTRIBUTION ON COMPLEXATION

The shifts of the Ka lines for P, S and Cl atoms were studied as functions of the effective charges on these atoms obtained using CNDO/S, CNDO/2, INDO, MINDO/3 and MNDO methods for model compounds. The best correlation for all three elements was obtained by the INDO method in a minimal basis set. The problem of electron density redistribution on complexation was investigated from the "viewpoint" of a ligand, taking AlBr3L complexes (L = PCl3, P(C6H5)3, SPCl3, OPCl3) as examples. Significant transfer of electron density from a ligand to the acceptor does not occur on complexation with AlBr3, but there is a significant increase in the PCl bond ionicity. The PS bond ionicity does not change on complexation.