Quantum Chemical Analysis Of The Reactivity Of A Ligand Synthesized From Melamine–Formaldehyde And Succinic Acid

Abstract

The rational design of multifunctional ligands with tailored reactivity is of significant interest in coordination chemistry, catalysis, and polymer science. In this work, a ligand synthesized conceptually from a melamine–formaldehyde framework and succinic (amber) acid is investigated using quantum chemical methods. Density Functional Theory (DFT) calculations were employed to analyze the electronic structure, molecular geometry, frontier molecular orbitals, global and local reactivity descriptors, and potential coordination behavior of the ligand. Optimized geometries were obtained at the B3LYP/6-31G(d,p) level of theory. Frontier orbital analysis reveals a moderate HOMO–LUMO energy gap, indicating balanced stability and chemical reactivity. Global reactivity descriptors such as chemical hardness, softness, electronegativity, and electrophilicity index were calculated to assess the ligand’s overall reactivity profile. Molecular electrostatic potential (MEP) maps and Fukui function analysis were used to identify nucleophilic and electrophilic reactive sites, particularly around the triazine nitrogen atoms and carboxylate oxygen atoms. The results suggest that the ligand exhibits strong donor capability and favorable coordination behavior toward transition metal ions, making it a promising candidate for applications in metal complex formation and functional materials. This study demonstrates the usefulness of quantum chemical analysis in predicting the reactivity and coordination potential of melamine-based ligands prior to experimental investigation.