Note Synthesis and characterization of new copper(II) and nickel(II) complexes of 3-(2?-hydroxyphenyl)-1,2,4-triazine derivatives Virginie Be ´reau a, *, Je ´ro ˆme Rey a , Eric Deydier a , Je ´ro ˆ me Marrot b a Laboratoire de Chimie Bioinorganique Me ´dicale, IUT Paul Sabatier, De ´partement de Chimie, Avenue Georges Pompidou, 81104 Castres Cedex, France b Institut Lavoisier, Universite ´ de Versailles-Saint-Quentin-en-Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex, France Received 18 October 2002; accepted 15 January 2003 Abstract The copper(II) and nickel(II) complexes of 5,6-diphenyl-3-(2?-hydroxyphenyl)-1,2,4-triazine, noted HL H , and 5,6-bis (4- methoxyphenyl)-3-(2?-hydroxyphenyl)-1,2,4-triazine, noted HL OMe , have been synthesized from copper(II) acetate in CH 2 Cl 2 and nickel(II) nitrate in acetone with an excess of previously deprotonated triazine. The new complexes [Cu(L H ) 2 ] × /H 2 O(1), [Cu(L OMe ) 2 ] × / 2H 2 O(2), Na[Ni(L H ) 3 ] × /2H 2 O × /(CH 3 ) 2 CO (3), and Na[Ni(L OMe ) 3 ] × /2H 2 O(4) were isolated as pure solids and characterized by IR, UV /Vis, elemental analysis and mass spectra. Copper(II) complexes 1 and 2 were studied by EPR, in frozen solutions. In accordance with the spectroscopic data obtained by UV  /Vis, the stoichiometry of the complexes was found to be 1:2 for Cu 2 :L H,OMe with a square planar environment for the metal centre. Crystals of HL OMe and 3 were obtained and studied by single crystal X-ray diffraction. The structure of HL OMe exhibits a strong deviation from planarity of the two p -methoxyphenyl rings with respect to the triazine ring while the 2-hydroxyphenyl fragment is almost coplanar. Intramolecular hydrogen bonding between one of the N atoms of the triazine ring and the phenol can explain this restraint. For 3, three L H bidentate triazines are coordinated to the nickel ion in a distorted octahedral manner. # 2003 Elsevier B.V. All rights reserved. Keywords: Copper(II) complexes; Nickel(II) complexes; 1,2,4-Triazine; EPR; Crystal structures 1. Introduction Numerous compounds containing the 1,2,4-triazine moieties are well known in natural materials and show interesting biological, pharmacological and medicinal properties. One of the important classes of N-containing heterocycles is the 3,5,6-trisubstituted-1,2,4-triazines. Some of them can be active as blood platelet aggrega- tion inhibitors and others exhibit antiviral inhibitory activity (against influenza viruses for example), signifi- cant activity towards leukaemia and ovarian cancer, and anti-HIV activity [1]. Another interesting property of the derivatives of 1,2,4-triazine compounds is that they form coloured complexes when they are coordinated to a metal ion. A wide range of 1,2,4-triazine complexes has been reported in the literature [2]. Among them, only a few papers have considered the potential biological or pharmaceu- tical activity of such complexes and more specifically of copper complexes [3,4]. This work focuses on the complexation ability of two 1,2,4-triazine derivatives towards Cu 2 and Ni 2 ions through an O  /N type coordination. The two selected ligands are 5,6-diphenyl-3-(2?-hydroxyphenyl)-1,2,4-tri- azine, noted HL H (Scheme 1), and 5,6-bis (4-methox- yphenyl)-3-(2?-hydroxyphenyl)-1,2,4-triazine, noted HL OMe (Scheme 1). The preparation of four 1,2,4- triazine-Cu 2 and -Ni 2 complexes and their charac- terizations are reported. For the future, attempts will be made to study the potential biological activity of the obtained copper complexes and to work with other N- containing heterocycles having biological implications such as those of the triazole family. * Corresponding author. Tel.:  /33-5-6362 1157; fax:  /33-5-6335 6388. E-mail address: virginiebereau@iut-tlse3.fr (V. Be ´reau). Inorganica Chimica Acta 351 (2003) 389  /394 www.elsevier.com/locate/ica 0020-1693/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0020-1693(03)00192-0