Structural and spectroscopic (UV–Vis, IR, Raman, and NMR) characteristics of anisaldehydes that are flavoring food additives: A density functional study in comparison with experiments

摘要: Abstract The molecular structures, vibrational spectra (IR and Raman), electronic (UV–Vis DOS), NMR (13C 1H) of p-anisaldehyde, m-anisaldehyde, o-anisaldehyde have been studied by using the B3LYP density functional 6-311++G** basis set. While p-anisaldehyde has found to contain two stable conformers at room temperature, m-anisaldehyde four conformers. In agreement with calculated ground-state energetics small transition barriers, comparison experimental anisaldehydes indicates equilibrium between all temperature. However, o-anisaldehyde, in which methoxy group lies out ring plane, are too rare equilibrium. conditions anisaldehyde isomers shown readily accessible through UV–Vis 13C spectral studies but requiring very detailed analyses. effect solvent red-shift absorption bands make more reactive soft. Molecular electrostatic potential maps show that their oxygen atoms sites for nucleophilic reactivity. Compared most sophisticated NBO method, ESP charges mostly reliable while Mulliken fail badly present large calculations reproduce not only characteristics also reveal several structural features.