Coordination behavior of chelidamic acid With VV, NiII, FeIII, and CaII: Syntheses, X-ray characterization and DFT studies

Four new complexes of 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)]⋅H2O (1), [Ni(Hcda)(apym)(H2O)2]⋅H2O (2), (apymH)[Fe(Hcda)2] (3), and (tataH)2(tata)2[Ca2(cda)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. Some complexes present remarkable assemblies in the solid state governed by unconventional noncovalent interactions that have been analyzed by means of DFT calculations. Solution studies were also performed to fully characterize the new compounds.