A new class of heterobinuclear complexes: Crystal structure and magnetism of copper(II)-nickel( II) complexes incorporating two different macrocyclicligands

Three novel oxamido-bridged heterobinuclear copper (II)-nickel(II) complexe s incorporating two different tetraazamacrocyclic compounds were synthesize d and characterized by IR. ESR. and electronic spectra. They are of the for mulas [(CuL1)Ni(rae-eth)](ClO)(42).H-2 O (1), [Cu(L-2)Ni(rae-eth)](ClO4)(2) .0.5 EtOH (2), and [(CuL3)Ni(rae-eth)](ClO1).H-2 O (3). L-1, L-1, and L-3 are the dianions of diethyl 5.6.7.8.16.17-hexahydro-6,7-dioxo-15H-dibenzo[e ,n][1.4.8.12]tetraazacyclopentadecine-13.19-diearboxylate. diethyl 5.6.7.8. 15.16-hexahy-dro-6,7-dioxodibenzo[1,4,8,11]tetraazacyclotetracine-13.18-dic arboxylate, and diethyl 5.6.7.8.15.16-hexahydro-15-methyl-6,7-dioxdibenzo[1 .4.8.11]tetraazacyclotetradecine-13.18-dicarboxylate, and diethyl 5.6.7.8.1 6.-hexahydro-15-methyl-6,7-dioxodibenzo[1.4.8.11]tetraazacyclotetradecine-1 3.18-dicarboxylate, respectively, and rae-eth is rac-5.7.7.12.14.14-hexamet hyl-1.4..8.11-tetraazacyclotetradecane. The crystal structures of 1 and 2 w ere determined by single-crystal X-ray analysis. The Ni-11 ion is pseudooet ahedrally coordinated. The coordination geometry around the Cu-11 ion in 2 is slightly distorted square planar, while that in 1 shows significant dist ortion towards a tetrahedral structure. The temperature dependence of the m agnetic susceptibility for 1 and 2 was analyzed by means of the Hamiltonian H- 2JS(1) .S-2- leading to J -63.9 and -67.9 and 67.4 cm(-1) for 1 and 2 r espectively.