Insights into the structural investigation of metal-complexes with 1,3-diamino-2-hydroxypropanetetraacetic acid: Inputs from X-ray and computational studies

Abstract

A new 1,3-diamino-2-hydroxypropanetetraacetate copper complex (1) [{Cu(Hpdta)}{Cu(H2O)6}] has been synthesized and structurally characterized by single crystal X-ray diffraction and compared with a similar cobalt complex (2) of H4Hpdta (H4Hpdta = 1,3-diamino-2-hydroxypropanetetraacetic acid) retrieved from CSD (CSD ref code: TELBAN) with a detailed analysis of intermolecular interactions. X-ray crystallography reveals that both complexes are stabilized through C−H⋯O and O−H⋯O interactions generating different supramolecular networks. Detailed analysis of Hirshfeld surfaces and 2D fingerprint plot has been carried out for the title complexes to quantify the intermolecular interactions. Further, the noncovalent interactions are characterized through the Bader’s theory of ‘Atoms in Molecules’ (AIM) and noncovalent interaction (NCI) plot index. At the bond critical point (BCP), the electron density (ρBCP) and the Laplacian of electron density (∇2(ρBCP)) differ significantly for strong and weak noncovalent interactions. The dissociation energies are evaluated for validating the intermolecular interactions required to stabilize the complexes. The analysis of topological parameters extracted from AIM calculation characterized the interactions as closed-shell interactions.