Preparation and spectral properties of nickel(II) and copper(II) complexes with two isomeric cyclohexylcyclams
作者:Kazunori Sakata、Takeharu Odamura、Yumie Kanbara、Tamami Nibu、Mamoru Hashimoto、Akihiko Tsuge、Yoshiki Moriguchi
DOI:10.1016/s0277-5387(97)00405-1
日期:1998.1
The nickel(II) complexes-of two isomeric cyclohexylcyclams were prepared by employing a nickel template reaction. The cyclohexylcyclams were synthesized from the nickel(II)-complexes and then the copper(II) complexes were prepared from the free ligands and copper(II) perchlorate. The nickel(II) and copper(II) complexes exhibit clusters of ions corresponding 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 assigned to the N-H stretching mode and the band is slightly shifted to lower frequency on metal coordination, indicating freshly strong bands due to ClO4- stretching mode at ca 1090 and ca 620 cm(-1). The molar conductances for the complexes are 1:2 electrolytes in N,N-dimethylformamide and the perchlorate anions are ionized on dissolution in the solvent. The nickel(II) and copper(II) complexes of the two isomers are subjected to the square,planar ligand-field, but the ligand-field band for the nickel(II) complex of isomer L-t(3), trans-cyclohexylcyclam, shows the distorted octahedral form in coordinating solvent. ESR spectra for the copper(II) complexes of the two isomers also give the spin Hamiltonian parameters of the square-planar coordination. C-13-NMR spectral results are com; parable with those of another spectra. (C) 1998 Elsevier Science Ltd. All rights reserved.