Syntheses and study on nickel(II) complexes with thiodiglycolic acid and nitrogen-donor ligands. X-ray structures of 6Ni(bpy)(tdga)(H2O)9a4H2O and 6(en)Ni($mu;-tdga)2Ni(en)9a4H2O (tdgaH2=thiodiglycolic acid)

Abstract

Mixed-ligand Ni(II) complexes involving thiodiglycolate(2−) anion (tdga) and nitrogen-donor ligands in the coordination sphere have been prepared. The complexes of composition [Ni(bpy)(tdga)(H2O)] · 4H2O (1), [(en)Ni(μ-tdga)2Ni(en)] · 4H2O (2), [Ni(phen)(tdga)(H2O)] (3), [Ni(1,8-dan)(tdga)(H2O)] (4), [Ni(nphen)(tdga)(H2O)] · H2O (5), [Ni(ampy)(tdga)(H2O)] (6), where bpy=2,2′-bipyridine, en=ethylenediamine, phen=1,10-phenanthroline, 1,8-dan=1,8-diaminonaphthalene, nphen=5-nitro-1,10-phenanthroline and ampy=2-(aminomethyl)-pyridine, have been characterized by elemental analysis, IR and UV–Vis spectroscopies, and magnetic susceptibility measurements. Room temperature effective magnetic moments for 1–6 are ranging from 3.06 to 3.28 μeff/μB. and thus indicating that nickel atoms are six-coordinated in a deformed octahedral arrangement in all the prepared complexes. This conclusion has been confirmed by single-crystal X-ray analysis of [Ni(bpy)(tdga)(H2O)] · 4H2O (1). A binuclear structure of complex [(en)Ni(μ-tdga)2Ni(en)] · 4H2O (2) has been anticipated in connection with study of its magnetic properties over the 1.8–300 K temperature range (J=−4.35 cm−1, D=5.53 cm−1, zJ=−0.94 cm−1 for g=2.00) and unambiguously proved by a single-crystal X-ray analysis.