Journal of Coordination Chemistry Vol. 63, No. 18, 20 September 2010, 3187–3197 Fe(III) and cobalt(II) coordination compounds of 5-bromo-6-methyl-2-morpholinepyrimidinium-4-amine pyridine-2,6-dicarboxylate HOSSEIN ESHTIAGH-HOSSEINI*, ZAKIEH YOUSEFI, MARYAM SHAFIEE and MASOUD MIRZAEI Department of Chemistry, School of Sciences, Ferdowsi University of Mashhad, Mashhad 917791436, Iran (Received 11 January 2010; in final form 13 May 2010) New coordination compounds, (bmmpaH)[Fe(pydc) 2 ]  (EtOH) 0.8 (H 2 O) 0.2 (1), (8QH) [Fe(pydc) 2 ]  H 2 O(2), (2ampyH) 2 [Mn(pydc) 2 ]  H 2 O(3), (2ampyH)[Cr(pydc) 2 ](2ampy) 0.5  H 2 O (4), [Co(H 2 O) 5 --(pydc)Co(pydc)]  2H 2 O(5), [Ni(pydcH) 2 ]  H 2 O(6), and [Cu(pydcH) 2 ](7), where bmmpa, 8Q, 2ampy, pydcH 2 are 5-bromo-6-methyl-2-morpholinepyrimidine-4-amine, 8-hydroxyquinoline, 2-amino-6-methylpyridine, and pyridine-2,6-dicarboxylic acid, respec- tively, have been synthesized and structurally characterized by elemental analyses, infrared, UV spectroscopic methods, and X-ray crystallography. Metal ions of 1 and 5 are six-coordinate with distorted octahedral geometries. Compound 1 is an anionic mononuclear complex and 5 is a binuclear compound constructed from cationic and anionic parts. The crystal data of 5 reveal that the cationic part is formed by five terminal waters and one -carboxylate oxygen O2 from the anionic portion and the anionic complex is built from two deprotonated (pydc) 2 moieties. In the compounds, pydcH 2 is tridentate by one nitrogen of pyridine ring and two oxygens of carboxylate. Keywords: Proton transfer compound; Pyridine-2,6-dicarboxylic acid; 5-Bromo-6-methyl-2- morpholinepyrimidine-4-amine; 2-Aminopyridine; Crystal structure 1. Introduction Aromatic multi-carboxylic acids have predictable and interesting supramolecular properties and capability of forming hydrogen bonds. Pyridinedicarboxylic acids (PDAs) as assembler ligands or proton donating in proton transfer methodology have been increasingly used [1–10]. It should be noted that PDAs are present in many natural products, such as alkaloids, vitamins, and co-enzymes, so their metal complexes can be used as models in many research fields, especially in food chemistry [11]. Many researchers have designed PDA derivatives to tune their coordination ability and biological activity. For instance, 1 : 1 complex of Ca 2þ –pydc 2 is important in spore resistance to many environmental stresses and in spore stability [12]. The (pydc) 2 possesses a variety of bonding abilities and exhibits strong hydrogen bonds during *Corresponding author. Email: heshtiagh@um.ac.ir Journal of Coordination Chemistry ISSN 0095-8972 print/ISSN 1029-0389 online ß 2010 Taylor & Francis DOI: 10.1080/00958972.2010.508284