Quantum chemical calculation for synthesis some thiazolidin-4-one derivatives

Abstract

In this study, outline the synthesis and spectroscopic characterization of novel 2-imino-thiazolidin-4-one derivatives. The synthesis process is divided into three main parts. Firstly, we prepared the starting material, 2-amino-4-(substitutedphenyl)-1,3-thiazole, by reacting thiourea with substituted acetophenone in the presence of iodine. The second part involved the synthesis of 2-chloroacetamido-4-(substitutedphenyl)-1,3-thiazole through the reaction of heterocyclic amine with chloroacetyl chloride in benzene. The third part focused on the cyclization reaction of synthesized intermediate compounds, leading to the formation of a new series of desired products, namely, 2-imino-3-[4-(substitutedphenyl)-1,3-thiazol-2-yl] thiazolidin-4-ones. The structures of the synthesized compounds were determined based on spectral data, including IR, 1HNMR, and 13CNMR. Various analytical methods were employed to explore intermolecular interactions, nonlinear optical properties, HOMO-LUMO energy gap, potential energy maps, Natural Bond Orbital (NBO) analysis, and thermodynamic parameters of diverse compounds. The assessment of weak intermolecular interactions using Noncovalent interactions (NCI) and reduced density gradient (RDG) methods revealed the presence of robust hydrogen bonds, van der Waals forces, and steric effects within the compounds. Topological parameters highlighted significant hydrogen bonding capabilities among the studied compounds. Additionally, the analysis of the HOMO-LUMO energy gap and other quantum chemical parameters unveiled the influence of protonation on polarization, chemical reactivity, and corrosion resistance. Molecular Electrostatic Potential (MEP) analysis indicated changes in electrophilicity and nucleophilicity upon the addition of protons, altering chemical reactivity. Stabilization energies of donor-acceptor interactions, assessed through Natural Bond Orbital (NBO) analysis, provided insights into charge transfer and conjugative interactions, particularly emphasizing electron delocalization within the compounds' phenyl rings.