Mol-ecular and crystal structure, Hirshfeld analysis and DFT investigation of 5-(furan-2-yl-methyl-idene)thia-zolo[3,4-a]benzimidazole-2-thione.

The thia-zolo[3,4-a]benzimidazole fused-ring system in the title compound, C14H8N2OS2, is nearly planar, the r.m.s. deviation being 0.0073 Å. The thia-zolo-benzimidazole-2-thione system is almost in the same plane as the furan-2-yl-methyl-ene moiety, with a dihedral angle of 5.6 (2)° between the two least-squares planes. In the crystal, adjacent mol-ecules are connected by weak inter-molecular inter-actions (C-H⋯N and slipped π-π stacking) into a three-dimensional network. The nature of the inter-molecular inter-actions was also qu-anti-fied by Hirshfeld surface analysis. DFT analysis indicates a good agreement of the experimentally determined and the theoretically calculated mol-ecular structures.

Synthesis, X-Ray Structure Determination and Related Physical Properties of Thiazolidinone Derivative by DFT Quantum Chemical Method.

In this paper we report the synthesis and characterization of the (Z)-3-N-(ethyl)-2-N'-((3-methoxyphenyl)imino)thiazolidine- 4-one by means of FT-IR, 1H and 13C NMR and by single crystal X-ray diffraction. The experimental determination of the crystal structure of the compound has been achieved using X-ray diffraction data. The important characteristic of the structure is the existence of a dihedral angle formed by the benzene and thiazolidinone rings being equal to 86.0° indicating an absence of α-α stacking as well as that the structure is non planar. In the crystal, the molecules are linked by C-H···O and C-H···N hydrogen bonds, these bonds being responsible for the three-dimensional molecular structure packing. In order to compare the experimental results with those of the theoretical calculation, quantum chemical DFT calculations were carried out using B3LYP/6-311G(d,p) basis set. In this context, the molecular electrostatic potential around the molecule and HOMO-LUMO energy levels were also computed. The dipole moment orientations were determined in order to understand the nature of inter- and intramolecular charge transfer. Finally, the stability of the title compound was confirmed throughout the calculation of the chemical reactivity descriptors.

Theoretical and experimental electrostatic potential around the m-nitrophenol molecule.

This work concerns a comparison of experimental and theoretical results of the electron charge density distribution and the electrostatic potential around the m-nitrophenol molecule (m-NPH) known for its interesting physical characteristics. The molecular experimental results have been obtained from a high-resolution X-ray diffraction study. Theoretical investigations were performed using the Density Functional Theory at B3LYP level of theory at 6-31G* in the Gaussian program. The multipolar model of Hansen and Coppens was used for the experimental electron charge density distribution around the molecule, while we used the DFT methods for the theoretical calculations. The electron charge density obtained in both methods allowed us to find out different molecular properties such us the electrostatic potential and the dipole moment, which were finally subject to a comparison leading to a good match obtained between both methods. The intramolecular charge transfer has also been confirmed by an HOMO-LUMO analysis.