Extended structures in copper(II) complexes with 4-hydroxypyridine-2,6-dicarboxylate and pyrimidine derivative ligands: X-ray crystal structure, solution and magnetic studies

Three new copper(II) complexes of chelidamic acid (H(3)cda) and pyrimidine derivatives, namely [Cu-2 (Hcda)(2)(ampym)(2)]center dot 5H(2)O (1) and [Cu-2(Hcda)(2)(apym)(H2O)(2)]center dot 2H(2)O (2), and (Hapym)(2)[Cu(Hcda)(2)]center dot 4H(2)O (3) (ampym = 2-amino-4-methylpyrimidine, apym = 2-aminopyrimidine) have been synthesised in mild conditions starting from the proton transfer compounds (Hampym)(2)(Hcda) and (Hapym)(2)(Hcda). X-ray diffraction analysis revealed the formation of extended structures featuring dinuclear (1 and 2 with pyrimidine derivatives as metal bridges) or mononuclear (3) Hcda(2) copper(II) complex units joined via H-bonds mainly involving coordinated and lattice water molecules and the coordinated Hcda(2) ligands. Solution studies, magnetic measurements and thermal analyses were performed to fully characterise the new compounds. (C) 2014 Elsevier B. V. All rights reserved.