CRYSTAL-STRUCTURES, SPECTROSCOPIC AND NONLINEAR-OPTICAL PROPERTIES OFMETAL-COMPLEXES OF SCHIFF-BASE LIGANDS CONTAINING NITROGEN AND SULFURDONORS

ML2 type Cu-II chelates with the Schiff base ligands R-C6H4CHNNHC(S)SC H2Ph (R = -NMe2 or -OMe) have been prepared and characterized. Spectro scopic data suggest that the Schiff bases act as singly charged anioni c bidentate ligands, forming stable neutral metal complexes. Magnetic and e.s.r. data support a square-planar coordination geometry for both complexes. Single crystal X-ray diffraction analysis of the complexes has established that the Schiff base ligand is deprotonated to give t he thiol tautomer, coordinated via the thiolato sulfur and beta-nitrog en. The geometry around the metal is square-planar with two equivalent Cu-N and Cu-S bonds; the two phenyl rings and the donor atoms are in one plane forming an extensive electronic delocalization system. Third -order optical nonlinearity measurements show that the complexes exhib it fairly large second-order hyperpolarizabilities.