PREPARATION AND SPECTRAL PROPERTIES OF NICKEL(II) AND COPPER(II) COMPLEXES WITH 2 ISOMERIC CYCLOHEXYLCYCLAMS

The nickel(II) complexes-of two isomeric cyclohexylcyclams were prepar ed by employing a nickel template reaction. The cyclohexylcyclams were synthesized from the nickel(II)-complexes and then the copper(II) com plexes were prepared from the free ligands and copper(II) perchlorate. The nickel(II) and copper(II) complexes exhibit clusters of ions corr esponding to [M-ClO4](+) and [M-2ClO(4)+-2H](+) which is the base peak in FAB mass spectra. A strong band observed at ca 3200 cm(-1) is assi gned to the N-H stretching mode and the band is slightly shifted to lo wer frequency on metal coordination, indicating freshly strong bands d ue to ClO4- stretching mode at ca 1090 and ca 620 cm(-1). The molar co nductances for the complexes are 1:2 electrolytes in N,N-dimethylforma mide and the perchlorate anions are ionized on dissolution in the solv ent. The nickel(II) and copper(II) complexes of the two isomers are su bjected to the square,planar ligand-field, but the ligand-field band f or the nickel(II) complex of isomer L-t(3), trans-cyclohexylcyclam, sh ows the distorted octahedral form in coordinating solvent. ESR spectra for the copper(II) complexes of the two isomers also give the spin Ha miltonian parameters of the square-planar coordination. C-13-NMR spect ral results are com; parable with those of another spectra. (C) 1998 E lsevier Science Ltd. All rights reserved.