Synthesis, physicochemical, conformation and quantum calculation of novel N-(1-(4-bromothiophen-2-yl)ethylidene)-2-(piperazin-1-yl)ethanamine Schiff base

N-(1-(4-bromothiophen-2-yl)ethylidene)-2-(piperazin-1-yl)ethanamine Schiff base ligand was prepared in very good yield by condensation of equimolar amounts of 1-(4-bromothiophen-2-yl)ethanone with 2-(piperazin-1-yl)ethanamine under reflux condition using alcohol media. The desired Schiff base was analyzed on the basis of its MS, elemental analysis, UV-visible, FT-IR and NMR analysis. The E and Z optimization was performed to figure out the most stable isomer. Several DFT quantum calculation like: TD-SCF, MPE, IR-vibration, NMR, Mulliken population were carried out by B3LYP level of theory. The experimental analyses of the compound were compared to their theoretical coordinates

Synthesis, structural exploration, spectral and combinatorial analysis of racemic-3-isobutyl-5-phenyl-5-(pyridin-4-yl)imida-zolidine-2,4-dione: Comparison between experimental and DFT calculations

New racemic 3-isobutyl-5-phenyl-5-(pyridin-4-yl)imidazolidine-2,4-dione was synthesized, isolated, characterized spectrally, thermally and finally the structure was confirmed by X-ray diffraction studies. Both XRD and DFT/B3LYP/6-31G(d,p) optimized structures of the compound revealed the diketo monomer as favored tautomer isomer structure. The molecular geometry optimization parameters were compared with the experimental XRD results. The electronic spectrum which allocated basis of the TD-SCF result and the MO energy level diagram were compared with the experimental one. The electrophilic and nucleophilic receptors and acceptor functional groups with their interactions on the molecule surface was established by packing diagrams and then compared with Hirshfeld surface, electrostatic potential map and Mullikan population theoretical calculations. The experimental 1H NMR results, compared to the theoretical ACD-lab and NMR-db showed an excellent agreement. The desired organic compound revealed a high thermal stability in an open atmosphere