Exploring Pyrimidine-Based azo Dyes: Vibrational spectroscopic Assignments, TD-DFT Investigation, chemical Reactivity, HOMO-LUMO, ELF, LOL and NCI-RDG analysis.

Theoretical computations of pyrimidine-based azo dyes were performed by the DFT approach using the B3LYP/6 - 31G(d,p) basis set. The molecules were optimized based on the same basis set by calculating the minimum energy. FMOs, DOS and GCRD were computed for kinetic stability and chemical reactivity of the selected compounds. The MEP surface was studied to locate nucleophilic and electrophilic attack zones. The energy gap was carefully studied for pyrimidine-based azo dyes. Vibrational spectroscopy was studied in the most prominent regions with respect to PED assignments. Similarly, the UV-Vis absorption technique was calculated using the TD-DFT approach in different solvent media. The electronic structure of each atom in a molecule was examined via the electron localization function (ELF) and localized orbital locator (LOL). Non-covalent interactions were explored using reduced density gradient analysis. The combination of experimental and theoretical data allowed us to correlate the structural modifications with the observed photophysical properties, facilitating the design of azo dyes with tailored characteristics. This work contributes to the fundamental understanding of azo dyes and offers a foundation for the development of new materials with enhanced photophysical and electronic properties.

Investigation of photophysical and electronic properties of aurone derivatives: Insights from spectroscopic techniques and density functional theory calculations.

This paper reports on a study of the photophysical properties, density functional theory (DFT) calculations, infrared (IR), ultraviolet (UV) and nuclear magnetic resonance (NMR) spectroscopic techniques of a series of aurone compounds. The photophysical properties were investigated using UV absorption and fluorescence spectroscopy in a dimethyl sulfoxide (DMSO) solution. Furthermore, the fluorescence quantum yields of the target compounds (1-24) were also investigated. Remarkably, these compounds revealed high quantum yields (Φ = 0.001-0.729) as compared to the already existing aurones in literature. The DFT calculations were performed to elucidate the electronic structure, energy levels and draw a comparison between experimental and theoretical findings. The simulated properties such as molecular frontier orbitals, the density of states, reactivity descriptors (GCRD), electrostatic potential distribution, transition density matrix, electron localization function (ELF) and localized orbital locator (LOL) have been calculated using DFT. The DFT calculations provided insight into the electronic structure and energy levels of the aurone compounds, while the IR and UV spectroscopy results shed light on their functional groups and electronic transitions, respectively. The results of this study contribute to a better understanding of the photophysical properties of aurone compounds and suggest their potential use in technological applications.

Synthesis, in-vitro, in-vivo anti-inflammatory activities and molecular docking studies of acyl and salicylic acid hydrazide derivatives.

Over the course of time several drugs have been synthesized and are available in market for the treatment of inflammation. However, they were unable to cure effectively and associated with side effects. To effectively deal with such diseases, heterocycles and their derivatives have gained their special position. For this reason 1,3,4-oxadiazole (15-16), 1,2,4-triazole (17-18), Schiff base (19-24) and 3,5-disubstituted pyrazole (25) derivatives were synthesized starting from salicylic acid and acyl acid hydrazides (12-14) as COX-1 and COX-2 inhibitors. In vivo anti-inflammatory activities were also tested by carrageenan-induced mice paw edema against albino mice of any sex. Structures of all the synthesized compounds were confirmed by FT-IR and 1H NMR analysis. Schiff base derivative of 4-amiontirazole (24) with IC50 value of 1.76 ± 0.05 (COX-2) and 117.8 ± 2.59 emerged as potent COX-2 inhibitor. Furthermore, we also performed in-vivo anti-inflammatory investigations by using carrageenan induced paw edema test. From in-vivo anti-inflammatory activities, it was found that after 1 h the maximum percentage inhibition 15.8% was observed by compound 14 which is comparable with that of the standard drug followed by the compound 18 with percentage inhibition of 10.5%. After 3 h, the maximum percentage inhibition was observed by compound 18 with 22.2% and compound 14 with 16.7%. After 5 h the maximum percentage inhibition was observed by compound 18 with 29.4% followed by compound 16 with 23.5%. We further explore the mechanism of the inhibition by using docking simulations. Docking studies revealed that the selective COX-2 inhibitors established interactions with additional COX-2 enzyme pocket residues.

Synthesis and antibacterial activity of substituted flavones, 4-thioflavones and 4-iminoflavones.

Synthesis of flavones, 4-thioflavones and 4-iminoflavones was carried out with the substitution of variable halogens, methyl, methoxy and nitro groups in the A, B and AB rings of the respective compounds and we also report here their antibacterial activity. Most of the synthesized compounds were found to be active against Escherichia coli, Bacillus subtilis, Shigella flexnari, Salmonella aureus, Salmonella typhi and Pseudomonas aeruginosa. Activity of 4-thioflavones and 4-iminoflavones was found to be higher than that of their corresponding flavone analogues. Investigated compounds having substituents like F, OMe and NO2 at 4'-position in ring-B exhibited enhanced activity and the presence of electronegative groups in the studied compounds showed a direct relationship to the antibacterial activity.