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

• Published in: Inorganic chemistry communications 2008-09, Vol.11 (9), p.1023-1026
• Main Authors: Pawlak, Piotr L., Malkhasian, Aramice Y.S., Sjlivic, Bojan, Tiza, Matthew J., Kucera, Benjamin E., Loloee, Reza, Chavez, Ferman A.
• Format: Article
• Language: English
• Subjects: Binuclear complex; Macrocyclic ligand; Ni(II); SQUID susceptometry; UV–vis spectroscopy; X-ray crystallography
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2008.05.014

A new binuclear nickel(II) complex, [Ni 2(tacud) 2(μ-H 2O)(μ-Cl) 2]Cl 2 (tacud = 1,4,8-triazacycloundecane), is reported. In this complex, Ni(II) centers are bridged by two chloro and one aqua ligand while terminal positions are capped by tacud ligands. Magnetic studies reveal that the complex is weakly ferromagnetic. A new synthetic binuclear nickel(II) compound ([Ni 2(tacud) 2(μ-H 2O)(μ-Cl) 2]Cl 2 ( 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 ( μ eff = 4.78 μ B) 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.