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Nanosecond time‐resolved resonance Raman spectroscopic and ab initio MO investigation of substituent effects on the triplet states of bromonaphthalenes
Author(s) -
Pan Duohai,
Shoute Lian C. T.,
Phillips David Lee
Publication year - 2000
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(200004)31:4<255::aid-jrs537>3.0.co;2-o
Subject(s) - raman spectroscopy , resonance (particle physics) , chemistry , ab initio , ab initio quantum chemistry methods , spectral line , bond strength , substituent , nuclear magnetic resonance , nanosecond , resonance raman spectroscopy , laser , atomic physics , molecule , stereochemistry , optics , organic chemistry , physics , adhesive , layer (electronics) , astronomy
Nanosecond time‐resolved resonance Raman spectra of the T 1 states and Raman spectra of the S 0 states of 1‐bromonaphthalene and 1,4‐dibromonaphthalene were measured. Ab initio calculations were also performed to determine the optimized geometries and vibrational spectra for the S 0 and T 1 states of 1‐bromonaphthalene and 1,4‐dibromonaphthalene were predicted. The results were compared with those previously found for 2‐bromonaphthalene and it was found that the Br atom substitution position and number both affect the changes in the C— Br bond in the T 1 and T n states. The intensities of the time‐resolved resonance Raman spectra indicate that the C— Br bond changes its structure much more in the T n state relative to the T 1 state of 2‐bromonaphthalene than 1‐bromonaphthalene or 1,4‐dibromonaphthalene. Possible implications of these substitution position effects on the ‘reluctant’ bond cleavage processes occurring from the T n states of bromonaphthalenes are discussed. Copyright © 2000 John Wiley & Sons, Ltd.