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 complexes of chelidamic acid and pyrimidine derivatives are synthesised.
• X-ray analysis revealed the formation of extended structures of di- and mononuclear units.
• Solution studies, magnetic measurements and thermal analyses are also performed.

Three new copper(II) complexes of chelidamic acid (H3cda) and pyrimidine derivatives, namely [Cu2(Hcda)2(ampym)2]·5H2O (1) and [Cu2(Hcda)2(apym)(H2O)2]·2H2O (2), and (Hapym)2[Cu(Hcda)2]·4H2O (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) Hcda2− copper(II) complex units joined via H-bonds mainly involving coordinated and lattice water molecules and the coordinated Hcda2− ligands. Solution studies, magnetic measurements and thermal analyses were performed to fully characterise the new compounds.

New copper(II) complexes of chelidamic acid and pyrimidine derivatives with extended structures, reveal the possibility of fine tuning antiferromagnetic properties within a narrow range of coupling constants.Figure optionsDownload as PowerPoint slide