The College of Education for Pure Sciences, Department of Chemistry, University of Basra, discussed a master’s thesis on (implicit hydrogen bonding in enaminotheions, a spectroscopic and computational study)
The thesis presented by the researcher (Maryam Abdel Karim Mohsen) included a computer study of the implicit hydrogen bonding of enaminothiones. The calculations were carried out using the Kaossian 16 computer software system. As for the theoretical levels used, they included each of the levels based on post-Hartrey Fock represented by the CCSD level and the MP2 level, in addition to the levels based on the density function theory represented by the functions wB97xD and B3LYP. These theoretical methods have been reinforced by the basic rules of Bübel, Doninck, Karlsruhe and Jensen: 6-311++G(d,p), cc-pVTZ, def2-ptvz and pc-2 respectively. He also calculated the potential energy curve for the path of the proton between the sulfur and nitrogen atoms, and it was found that the voltage curve agrees with the curve of the strong implicit hydrogen bond. The electronic spectra of the binary molecule were also calculated using the time-dependent density function theory at the theoretical level B3LYP/cc-pVDZ in ethanol. she has. The electronic transitions responsible for them have been explained in terms of molecular orbitals, and the transitions were mostly from pi to pi type. In addition, the vibrational spectra of the enaminothione dimer were calculated and the resulting spectrum was interpreted. One of the main objectives of the study was to investigate the effect of structure on the implicit hydrogen bonding in molecules. Therefore, the electronic structures of the monomeric thioainaminone were studied with different motive and electron-pulling compensators, and their geometrical optimization was done at the theoretical level MP2/6-311++G(d,p). ). The hydrogen bond strength was analyzed on the basis of various electronic structural properties, which included the distance N…S, the lengths of the N-H bonds, S…H, and the angle value N-H…S. Calculations based on Peder's theory or atomic-in-molecular theory were performed to explain the hydrogen affinity based on the topological properties of the electronic distribution within these molecules. Among the studied topological properties were the critical point of the BCP ρ and the ring critical point RCP ρ. Each of these variables has linear relationships and a good correlation constant, which is consistent with similar studies conducted on systems characterized by implicit hydrogen bonding.
The message aims to
The study of the implicit hydrogen bonding in the enaminotheions, as they provide an appropriate model for the molecules containing the hydrogen bond, in order to search for finding relationships between the strength of the hydrogen bond and the structural properties of the studied molecules in an attempt to provide a better understanding of the phenomenon of hydrogen bonding.
Recommended letter
We recommend the use of enaminothiones as model molecules to study the implicit hydrogen affinity