Resonance Raman intensity analysis of the excited-state proton-transfer dynamics of 2-hydroxybenzaldehyde in the charge-transfer/proton-transfer absorption band.
Resonance Raman spectra were obtained for 2-hydroxybenzaldehyde (OHBA) in cyclohexane solution with excitation wavelengths in resonance with the first charge-transfer/proton-transfer (CT/PT) band absorption. These spectra indicate that the Franck-Condon region photodissociation dynamics have multidimensional character with motion predominantly along the nominal C=CH in-plane bend+ring deformation modes (nu9, nu10, nu14, nu16, nu18, nu19, nu20, nu26, nu30, nu31, and nu35) accompanied by a smaller amount of motion along the nominal C=O stretch mode (nu7), the nominal C=C-C(=O) in-plane bend modes (nu33 and nu37), and the nominal ring C-O-H in-plane bend modes (nu9 and nu14). A preliminary resonance Raman intensity analysis was done, and these results for the OHBA molecule were compared to results previously reported for the 2-hydroxyacetophenone (OHAP) molecule. Several proton-transfer tautomers in the ground and excited states were predicted from the results of B3LYP/cc-PVTZ, UB3LYP/cc-PVTZ, and CASSCF/cc-PVDZ level of theory computations. The differences and similarities between the CT/PT band resonance Raman spectra and the vibrational reorganizational energies for the OHBA molecule relative to those for the OHAP molecule are briefly discussed.
Jiang
Xue-Lian
XL
Department of Chemistry and State Key Laboratory of ATMMT(MOE), Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China.
Pei
Ke-Mei
KM
Wang
Hui-Gang
HG
Zheng
Xuming
X
Fang
Wei-Hai
WH
Phillips
David Lee
DL
D000447:Aldehydes / Q000737:chemistry*; D011522:Protons; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013237:Stereoisomerism; D013816:Thermodynamics
D000447:Aldehydes; D011522:Protons; C013243:salicylaldehyde