Synthesis, structure, and magnetic properties of a new binuclear Ni(II) complex supported by 1,4,8-triazacycloundecane

A new synthetic binuclear nickel(II) compound ([Ni2(tacud)2(μ-H2O)(μ-Cl)2]Cl2 (1); tacud = 1,4,8-triazacycloundecane) is reported. Compound 1 contains two Ni(II) ions bridged by two chloro and one aqua ligand resulting in a short Ni···Ni distance of 3.0187(10) Å. Each nickel is capped by terminal tacud ligands and possesses distorted octahedral geometry. This compound exhibits a new structural motif for metal complexes supported by tacud. Compound 1 exhibits two solvent dependent transitions in the UV–vis spectrum. Variable temperature SQUID magnetic susceptometry studies on 1 indicate mild ferromagnetism exists at room temperature (μeff = 4.78 μB) which increases upon temperature lowering. Magnetic analysis of 1 in the temperature range 2–300 K confirm weakly ferromagnetic behavior with J = +2.28 cm−1.