-4-YLMETHYLIDENE)-1,3-PROPANEDIAMINATO)NICKEL(II)] BRIDGED BY DI-MU-PHENOXO MOIETY AND THE DEPROTONATED IMIDAZOLATE-BRIDGED CYCLIC-TETRANUCLEAR COMPLEX

Protonated and deprotonated forms of nickel(II) complex with henylimid azol-4-ylmethylidene)-1,3-propanediamine, 1 and 1', were synthesized a nd characterized. The X-ray crystal structures of 1 . H2O and 1' were determined: 1 . H2O, P2(1)/n (No. 14), a = 11.642(2), b = 12.908(3), c = 15.264(2) Angstrom, beta = 96.642(1)degrees; 1', I4(1)/a (No. 88), a = 22.651(3), c = 13.950(7) Angstrom. The crystal of 1 . H2O assumes a dinuclear structure bridged by the di-mu-phenoxo moiety in an out-of -plane fashion with Ni-Ni = 3.173(1) Angstrom and Ni-O = 2.126(3) Angs trom of the Ni2O2 core and two perchlorate ions as counter anions, in which the nickel(II) ion assumes an octahedral coordination geometry w ith N3O3 donor atoms consisting of four donor atoms of a quadridentate ligand, a bridging phenoxo-oxygen atom, and an oxygen atom of methano l. A ferromagnetic interaction with J = +7.1 cm(-1) operates between t he two high-spin nickel(II) ions. 1 undergoes a deprotonation of the i midazole proton under basic conditions to give the deprotonated comple x 1'. The crystal of 1' consists of an electrically-neutral imidazolat e-bridged cyclic-tetranuclear molecule with Ni-Ni = 6.339(2) Angstrom and Ni-N = 2.051(7) Angstrom, in which the nickel(II) ion assumes a sq uare-pyramidal geometry with N4O donor atoms consisting of the quadrid entate ligand and an imidazolate nitrogen of the adjacent nickel(II) c omplex. An antiferromagnetic interaction with J = -6.3 cm(-1) is obser ved between the adjacent nickel(II) ions through the imidazolate group . Since the corresponding deprotonated copper(II) complex with the sam e ligand assumed an imidazolate-bridged zigzag-chain structure, the re sult with the nickel(II) complex demonstrates a very marked influence of the metal ion on the formation of the assembly structure.