1,1-Dimethyl-3-phenylurea (known as fenuron) which is a phenyl urea-based widely used herbicide exhibits interesting structural and conformational properties and a notable biological activity. A detailed analysis on the vibrational, molecular and electronic characteristics of fenuron has been carried out. Potential energy scans (PESs) performed at the B3LYP/6-311++G(d,p) level of theory predicted two possible minima corresponding to the optimized anti and synforms resulting from the internal rotation about the N-C bond. The presence of an auxochrome together with the interaction with DMSO solvent exhibited a blue shift corresponding to the C=O orbitals. Delocalization of HOMO and LUMO orbital facilitated the charge transfer effect in the molecule. The calculated HOMO-LUMO energies, chemical potential, energy gap and global hardness suggested a low softness value for the compound while its biological activity was described by the value of electrophilicity. Chlorine substitution in the phenyl ring influenced the orbital delocalization for ortho and para substitutions but that of meta remained unaffected. NLO properties were noticed to increase due to chlorine substitution in the parent molecule. The docking results suggested that the compound exhibits an inhibitory activity against mitochondrial ubiquinol-cytochrome-c reductase and can be developed as a potential anticancer agent.

The organic molecule tenoxicam and similar derivatives, piroxicam and isoxicam have been studied by quantum chemical theory (DFT), FT-Raman and FT-IR. By FMOs energies the charge transfer inside the molecules are obtained. The UV-Vis spectra of the compounds are simulated to study the electronic transition in the target molecules. By using natural bond orbital (NBO), charge delocalization analyzes arising from hyper conjugative interactions and the stability of the molecules are obtained. First order hyperpolarizability of piroxicam is higher than that of isoxicam and tenoxicam. The reactive areas are thoroughly studied by MEP. Prediction of Activity Spectra gives activities, anti-inflammatory, CYP2C9 substrate and gout treatment. Docked ligands form a stable complex with the receptors.