Syntheses,Structure and Magnetism of Heterobinuclear mu-Oxamido Cu(II)-Ni(II)Complexes Containing tacn as a Terminal Ligand

摘要

Two new heterobinuclear complexes,namely Ni(tacn)Cu(oxpn)(ClO_4)_2 centre dot 2H_2O(1)and Ni(tacn)Cu(pmoxd)(ClO_4)_2 centre dot CH_3OH(2),have been prepared from the planar fragments Cu(oxpn)and Cu(pmoxd)(tacn denotes 1,4,7-triazacyclononane,oxpn and pmoxd stand for the dianions of N,N'-bis(3-aminopropyl)oxamide and N,N'-bis(2-pyridyl-methyl)oxamide,respectively).Compound 1 crystallizes in the triclinic system,space group Pi,with a= 8.573(2),b= 12.808(3),c= 13.122(3)A,alpha= 99.63(3),beta=104.72(3)and gamma= 96.45(3)deg at 299 K,Z= 2.The Cu(II)ions are in square-pyramidal surroundings and the Ni(II)ions in octahedral surroundings.The temperature dependence of the magnetic susceptibilities of 1 has been studied in the 5-300 K range,giving the exchange integral J= -92.7 cm~(-1).This value,while close to those reported for other Cu(II)-Ni(II)complexes involving Cu(oxpn),represents the minimum exchange constant of such heterobinuclear system.