Synthesis, structural, spectroscopic, intermolecular interactions, kinetic stability, charge transfer method with DNA bases and electronic properties of (E)-3-(2-ethoxyphenyl)-5-(3-(2-methoxyphenyl)-4methylthiazol-2(3H)-ylidene)-2-thioxothiazolidin-4-one: Computational and experimental approach

Abstract

In the current paper, the new molecule (E)-3-(2-Ethoxyphenyl) -5-(3-(2methoxyphenyl) -4 methylthiazol-2(3H) -ylidene) -2-thioxothiazolidin-4-one (EMTh2) was synthesized and characterized using FT-IR, UV-vis, NMR, and X-ray diffraction experimental techniques. The experimental structure was determined from single-crystal X-ray diffraction data at low temperature (173 K). The compound crystallizes in the monoclinic system and space group P21/c with cell parameters: a=11.1100(5) Å, b=13.0597(6) Å, c=15.2343(7) Å, β=103.480(5)°, Z=4. R= 0.0512 was the final value for 4372 observed reflections. The two thiazol rings are coplanar, while the ethoxyphenyl and methoxy phenyl rings are essentially perpendicular to these rings with dihedral angle values of 107.2° for C4-N2-C8-C13 and 101.7° for C3-1-C15-C20. All theoretical calculations are performed using DFT with B3LYP functional and 6-31G(d,p) basis set. Both theoretical and experimental molecular structures were investigated and compared to one another. Furthermore, Hirshfeld surface analysis was performed to display surface contours and 2D-fingerprint plots were used to obtain contributions of the most important intermolecular interactions. The theoretical UV-vis spectrum was computed in chloroform as a solvent using the TD-DFT method. 1H and 13C-NMR chemical shifts were calculated using the GIAO approximation and the results were compared to the experimental ones. In addition, natural bond orbital (NBO), global reactivity parameters, MPA and NPA atomic charges, molecular electrostatic potential, Fukui functions were estimated using the same level of theory. The interactions between the investigated molecule and DNA bases (mainly adenine, cytosine, guanine, and thymine) were explored using the electrophilicity-based charge transfer method.