ELECTRON-DENSITY REDISTRIBUTION ON COMPLEXATION IN NON-TRANSITION ELEMENT COMPLEXES

Complexes of tin, antimony, silicon, germanium, iodine, boron and tita nium halogenides with organic ligands were investigated using nuclear quadrupole resonance (NQR) and X-ray fluorescence spectroscopies, and Mossbauer effect and quantum-chemical calculations. A discussion of re sults which we obtained previously as well as literature data is inclu ded. The correlations between Cl-35 NQR and ClKalpha line shifts in Sn Cl4L2, SbCl5L and TiCl4L2 complexes were obtained. The geometry of the acceptor was found to influence the value of the effective charge on the chlorine atom (q(Cl)) in SnCl4L2 complexes, but not to influence t he chlorine atom in TiCl4L2 complexes. Values of q(Sn) and q(Sb) were calculated from Mossbauer isomer shifts in the SnCl4L2 and SbCl5L comp lexes. Electron-density transfer from the ligand to the vacant d orbit al of the central atom on complexation was observed.