Crystal structure of a carboxylate-bridged chain and a mononuclear complex of nickel and the magnetic behaviour of [Ni(dtma)(Him)]n[ClO4]n(Hdtma = diethylenetriamine-N′-acetic acid, Him = imidazole)

Abstract

The molecular structures of a carboxylate-bridged chain and a mononuclear complex of nickel(II) with dtma (Hdtma = diethylenetriamine-N′-acetic acid) and Him (Him = imidazole) ligands were determined by single-crystal X-ray analysis. The complex [Ni(dtma)(Him)]_n[ClO₄]_n1 crystallizes in the monoclinic system, space group P2₁/c, with a= 8.255(1), b= 16.918(3), c= 11.114(1)Å and β= 104.77(1)° and the complex [Ni(dtma)(Him)₂]ClO₄·H₂O 2 in the orthorhombic system, space group P2₁2₁2₁, with a= 9.940(3), b= 12.917(3) and c= 14.602(3)Å. The crystal structure of complex 1 contains chains of carboxylate-bridged nickel(II) metal ions. Its variable-temperature (1.8–300 K) magnetic susceptibility was determined. The carboxylate bridge in complex 1 could only mediate a very weak ferromagnetic exchange interaction and the magnetic behaviour is better explained by single-ion anisotropy.