Synthesis and structural characterization of mono- and dinuclear Ni super(II) and Pd super(II) complexes derived from tetradentate 1,7-bis-(pyridin-2-yl)-2,6-diaza-1,6-heptadiene

• Published in: Journal of coordination chemistry 2013-07, Vol.66 (14), p.2477-2488
• Main Authors: Roberto Pioquinto-Mendoza, J, Olvera-Mendoza, David G, Andrade-Lopez, Noemi, Alvarado-Rodriguez, Jose G, Moreno-Esparza, Rafael, Flores-Alamo, Marcos
• Format: Article
• Language: English
• Subjects: Diffraction
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2013.806985

The reaction of Schiff base 1,7-bis-(pyridin-2-yl)-2,6-diaza-1,6-heptadiene (L) with either NiCl sub(2).6H sub(2)O or [Pd super(II)Cl sub(2)(CH sub(3)CN) sub(2)]/Na[BF sub(4)] in 1 : 1 stoichiometry yielded mononuclear ionic complexes, trans-[Ni super(II)(L)(H sub(2)O) sub(2)]Cl sub(2).3H sub(2)O (1.3H sub(2)O) and [Pd super(II)(L)][BF sub(4)] sub(2) (2), respectively; the reaction of L with [Pd super(II)Cl sub(2)(CH sub(3)CN) sub(2)] in 1 : 2 ratio yielded dinuclear cis-[Pd super(II) sub(2)( mu -L)Cl sub(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 super(II). Complex 1 has distorted octahedral geometry around Ni super(II) and an extended hydrogen-bond network; distorted square planar geometry around Pd super(II) in 2 and 3 was observed.