COMPLEXES OF A NEW BIDENTATE CHELATING PYRIDYL SULFONAMIDE LIGAND WITH COPPER(II), COBALT(II) AND PALLADIUM(II) - CRYSTAL-STRUCTURES AND SPECTROSCOPIC PROPERTIES/

Reaction of the bidentate ligand 2-(2-aminophenyl) pyridine with p-tol uenesulfonyl chloride afforded the new bidentate ligand HL which conta ins potentially chelating pyridyl and (protonated) sulfonamide N-donor binding sites. The crystal structure of the ligand shows that the sul fonamide NH proton is involved in a hydrogen-bonding interaction with the pyridyl N atom, resulting in a near-coplanar arrangement of the py ridyl and phenyl rings. Reaction of HL with various metal(II) acetates (M = Cu, Co, Pd) affords the neutral complexes [ML2] in each case in which the sulfonamide is deprotonated. All of these have been crystall ographically characterised; the Cu(II) and Pd(II) complexes are planar , whereas the Co(II) complexes is pseudo-tetrahedral with the two CoN2 planes at 85 degrees to one another. Appropriate spectroscopic and el ectrochemical studies on the complexes are described. (C) 1998 Elsevie r Science S.A. All rights reserved.