Synthesis, crystal structure and magnetic properties of N1,N2-bridged polynuclear Ni(II) complexes

A series of nickel(II) complexes [Ni-3(L1)(6)(H2O)(6)]Cl(6)(.)10H(2)O (1), [Ni-3(L2)(6)(H2O)6](NO3)(5)(OH)-2H(2)O (2) and [Ni-2(mu-pz)(3)(tpm)(2)](OH)(.)0.5H(2)O-C2H5OH (3) were synthesized and structural characterized via X-ray single-crystal diffraction (L1 =3,5-dimethanyl-4-amino-1,2,4-triazole, L2=4-2-pyridinyl-1,2,4-triazole, Hpz=pyrazole, tmp=tris(pyrazolyl)methane). I and 2 are linear trinuclear cations while 3 has a dinuclear Ni(II) unit, all of which contain bridged triazole or pyrazole ligands with N1,N2-bridged motif. UV-vis spectra of 1-3 show typical octahedral coordination field for Ni(11) ions. The variable-temperature (2-250 K) magnetic measurements reveal the existence of weak anti-ferromagnetic interaction in 1. (c) 2005 Elsevier B.V. All rights reserved.