A new family of Co(II), Ni(II), Fe(II) triple helicate systems on 5,5′-di(pyridin-2-yl)-3,3′-bi(1,2,4-triazole) basis: Synthesis, structure and magnetic studies

Abstract

Reaction of 5,5′-bi(pyridin-2-yl)-3,3′-bi(1,2,4-triazole) (H2L) with Ni(II), Co(II) and Fe(II) nitrates generates three novel dinuclear triple helicate complexes. Obtained compounds fully characterized by elemental analysis, UV-Vis and IR-spectroscopy. Moreover, the triple-helical structure of was con-firmed by X-ray in solid state and by ESMS-studies in solution. Complexation behavior was studied by UV-Vis spectrophotometric titration experiments that revealed the formation of species with 2:3 metal - ligand molar ratio. The magnetic properties of the Ni(II), Co(II) and Fe(II) are dominated by weak antiferromagnetic interactions (altogether with spin-orbital coupling in the Co(II) case). The magnetic studies of air and vacuum dried Iron complex samples indicate that lattice water molecules directly affect the magnetic behavior of these complexes.