Conformational landscape, stability, potential energy curves and vibrations of 1,2,3,4 tetrahydroquinoline

摘要: Abstract The twisted conformer with the equatorial hydrogen of NH group is computed to be most stable tetrahydroquinoline in S0 and S1 states at various levels quantum chemical computations. planar structure for orientation H atom found higher by 4000 ± 800 cm−1 ∼3000 cm−1 S1. For axial barrier 9500 ± 300 cm−1 ∼8000 cm−1 twisting angle optimized 29° ± 2° S0. Observed IR spectra corroborate well theoretical calculations. characteristic low-frequency vibrations appear 97 cm−1 154 cm−1 excited state differs from termed “half-twist”. Potential energy curves corresponding bending motions, as one connecting two motions are out. Frontier molecular orbital calculations associated electron density plots clearly identify changes on excitation. Molecular electrostatic potential calculated sites electrophilic interactions noted. Hardnesses' electrophilicities all conformers check their relative stability. maximum hardness principle minimum electrophilicity principles not valid conformers. Transition obey principle.