Fluorescence and solvent-dependent phosphorescence studies of o-nitrobenzaldehyde: a combined experimental and theoretical investigation.
The fluorescence and phosphorescence emission studies have been performed to understand the photochemistry of o-nitrobenzaldehyde in solution upon photoexcitation to the first excited singlet state (S(1)). The presence of an energy barrier in the S(1)-state hydrogen transfer potential energy surface is determined experimentally through the observed dual fluorescence emission, and the barrier height is estimated to be about 84-87 kcal mol(-1) by gradually decreasing the excitation energy. The phosphorescence spectra of o-NBA in five different solvents are observed for the first time, providing direct experimental evidence on the existence of triplet manifold in the photoexcitation of o-NBA. Furthermore, the relative phosphorescence quantum yield is found to be solvent dependent. To get further insights into the dynamic process involved in the photochemistry of o-NBA, excited state calculations at the TD-B3LYP/6-311+G(d,p) level of theory with the PCM model are accomplished, which strongly support our experimental findings.
Cheng
Shibo
S
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Song
Peng
P
Yang
Songqiu
S
Yin
Hongming
H
Han
Keli
K
D001547:Benzaldehydes / Q000737:chemistry*; D008962:Models, Theoretical; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
D001547:Benzaldehydes; D012997:Solvents; C043850:2-nitrobenzaldehyde