名称:
Synthesis and structural characterization of mono- and dinuclear NiIIand PdIIcomplexes derived from tetradentate 1,7-bis-(pyridin-2-yl)-2,6-diaza-1,6-heptadiene
摘要:
The reaction of Schiff base 1,7-bis-(pyridin-2-yl)-2,6-diaza-1,6-heptadiene (L) with either NiCl26H2O or [(PdCl2)-Cl-II(CH3CN)(2)]/Na[BF4] in 1:1 stoichiometry yielded mononuclear ionic complexes, trans-[Ni-II(L)(H2O)(2)]Cl-23H2O (13H2O) and [Pd-II(L)][BF4](2) (2), respectively; the reaction of L with [(PdCl2)-Cl-II(CH3CN)(2)] in 1:2 ratio yielded dinuclear cis-[Pd-II (2)(-L)Cl-4] (3). Complexes 1-3 were characterized by vibrational spectroscopy and X-ray diffraction; diamagnetic 2 and 3 were also characterized by NMR in solution. The molecular structures of 1 and 2 displayed tetradentate coordination of L with formation of two five-membered and one six-membered chelate rings for both complexes. In 3, L showed bidentate coordination mode for each pyridylimine toward Pd-II. Complex 1 has distorted octahedral geometry around Ni-II and an extended hydrogen-bond network; distorted square planar geometry around Pd-II in 2 and 3 was observed.