Synthesis and characterization of a novel tetranuclear nickel(II) complex: [Ni4(μ-OH)2(μ-dppn)4(μ-H2O)2](Cl)(ClO4)5·9H2O (dppn=3,6-bis(2-pyridyl)pyridazine)

A novel tetranuclear compound [Ni4(μ-OH)2(μ-dppn)4(μ-H2O)2](Cl)(ClO4)5·9H2O (1) (dppn = 3,6-bis(2-pyridyl)pyridazine) has been synthesized for the first time and structurally characterized. The pair of nickel atoms that are connected by the (μ-dppn) ligand are joined through the hydroxy group and water molecule bridges to form the tetranuclear core. Within this tetranuclear unit, one nickel atom is six-coordinate with distorted octahedral geometry and an N4O2 donor set from two equivalent dppn ligands and two oxygens of the bridging hydroxy and water molecule. Electronic spectra and magnetic moment of the complex also reveal a high-spin octahedral geometry.