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

摘要

Three new copper(II) complexes of chelidamic acid (H3cda) and pyrimidine derivatives, namely [Cu_2 (Hcda)_2(ampym)_2]·5H_2O (1) and [Cu_2(Hcda)_2(apym)(H_2O)_2]·2H_2O (2), and (Hapym)_2[Cu(Hcda)_2]·4H_2O (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.