Coordination behavior of chelidamic acid with V(V), Ni(II), Fe(III), and Ca(II): Syntheses, X-ray characterization and DFT studies

Abstract

Four new complexes of 4-hydroxypyridine-2,6-dicarboxylic acid or chelidamic acid (H3cda) in the presence of 2-aminopyrimidine (apym) or 2,4,6-triamino-1,3,5-triazine (tata) as external ligands, namely (apymH)[VO2(Hcda)2]∙H2O (1), [Ni(Hcda)(apym)(H2O)2]∙H2O (2), (apymH)[Fe(Hcda)2] (3), and (tataH)2(tata)2[Ca2(Hcda)2(H2O)6]∙H2O (4) were synthesized. X-ray diffraction analysis of 1-4 revealed the formation of 3D frameworks generally involving weak interactions (mainly H-bonds) between metal complexes of chelidamic acid, protonated or deprotonated external ligands apym or tata and co-crystallized water molecules. Solution studies were also performed to fully characterize the new compounds.