Syntheses and study on nickel(II) complexes with thiodiglycolic acid and nitrogen-donor ligands. X-ray structures of [Ni(bpy)(tdga)(H 2 O)] Æ 4H 2 O and [(en)Ni(l-tdga) 2 Ni(en)] Æ 4H 2 O (tdgaH 2 ¼ thiodiglycolic acid) Pavel Kopel a, * , Zden ek Tr avn  ı  cek a , Jarom  ır Marek b , Jerzy Mrozinski c a Department of Inorganic Chemistry, Faculty of Science, Palack y University, K r  ı  zkovsk eho 10, CZ-771 47 Olomouc, Czech Republic b Laboratory of Functional Genomics and Proteomics, Faculty of Science, Masaryk University, Kotl a rsk a 2, CZ-611 37 Brno, Czech Republic c Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, PL-50 383 Wroclaw, Poland Received 6 January 2004; accepted 16 March 2004 Available online 20 April 2004 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)(H 2 O)] Æ 4H 2 O (1), [(en)Ni(l-tdga) 2 Ni(en)] Æ 4H 2 O (2), [Ni(phen)(tdga)(H 2 O)] (3), [Ni(1,8-dan)(tdga)(H 2 O)] (4), [Ni(nphen)(tdga)(H 2 O)] Æ H 2 O(5), [Ni(ampy)(tdga)(H 2 O)] (6), where bpy ¼ 2,2 0 -bipyridine, en ¼ ethylenediamine, phen ¼ 1,10-phenanthroline, 1,8-dan ¼ 1,8-diaminonaphthalene, nphen ¼ 5-nitro-1,10- phenanthroline and ampy ¼ 2-(aminomethyl)-pyridine, have been characterized by elemental analysis, IR and UV–Vis spectros- copies, and magnetic susceptibility measurements. Room temperature effective magnetic moments for 1–6 are ranging from 3.06 to 3.28 l eff =l B . 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)(H 2 O)] Æ 4H 2 O(1). A binuclear structure of complex [(en)Ni(l-tdga) 2 Ni(en)] Æ 4H 2 O(2) has been anticipated in connection with study of its magnetic properties over the 1.8–300 K temperature range (J ¼4:35 cm 1 , D ¼ 5:53 cm 1 , zJ ¼0:94 cm 1 for g ¼ 2:00) and unambiguously proved by a single-crystal X-ray analysis. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Nickel(II); Thiodiglycolic acid complexes; X-ray structures; Magnetic properties 1. Introduction Transition metal complexes of carboxylic acids are in the interests of many research workers for many years. The complexes are often studied not only for their inter- esting magnetic properties but also for their biological occurrence in living organisms in metalloenzymes. It is well known that there are many possibilities for bonding of carboxylato group including also bridging properties [1,2]. More complicated systems are obtained in the case of polycarboxylic acids in comparison with monocar- boxylic ones. For instance, thiodiglycolic acid belongs to dicarboxylic acids and moreover, it contains sulfur atom which can also takes part in coordination to central atom. To date, some transition metal complexes involving thi- odiglycolic acid were characterized by single-crystal X-ray analysis, e.g. Cd(II), Zn(II), Ni(II), Cu(II) and Nd(III) [3–9]. From the X-ray study follows that the compounds can be either mononuclear, with one- or two- coordinated carboxylato groups, or polynuclear with tdga mostly forming linear chains having uncoordinated sulfur atom. The coordination sphere of a central atom in these systems may be completed by coordination of water molecules and/or nitrogen-donor ligands. In our recent work, we have prepared and studied binuclear copper(II) complexes of the composition * Corresponding author. Tel.: +420-58-563-4354; fax: +420-58-522- 5737. E-mail address: kopel@risc.upol.cz (P. Kopel). 0277-5387/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.poly.2004.03.005 Polyhedron 23 (2004) 1573–1578 www.elsevier.com/locate/poly