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Transient resonance Raman spectroscopic and ab initio MO investigation of substituent effects on the T 1 triplet states of halobiphenyls
Author(s) -
Lee Cheong Wan,
Pan Duohai,
Shoute Lian C. T.,
Phillips David Lee
Publication year - 2001
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/jrs.720
Subject(s) - biphenyl , electronegativity , chemistry , raman spectroscopy , resonance (particle physics) , halogen , polarizability , ab initio quantum chemistry methods , ab initio , steric effects , atom (system on chip) , computational chemistry , crystallography , stereochemistry , molecule , atomic physics , organic chemistry , physics , alkyl , optics , computer science , embedded system
Nanosecond transient resonance Raman spectra of the T 1 states and Raman spectra of the S 0 states of nine halogenated biphenyl compounds were obtained and ab initio computations were performed to determine the optimized geometry and vibrational wavenumbers of the T 1 and S 0 states of 10 halogenated biphenyl compounds. Substitution of halogen atoms at meta or para positions relative to the interring C—C bond leads to little change in the structure of the halogenated biphenyl compounds relative to the corresponding S 0 and T 1 states of biphenyl. Substitution of halogen atoms at ortho positions results in significant increases in the twisting between the two phenyl rings of the S 0 and T 1 states of the halogenated biphenyl compounds relative to the S 0 and T 1 states of biphenyl. The degree of twisting between the two phenyl rings in ortho ‐substituted halogenated biphenyls appears to depend on the steric, electronegativity and/or polarizability properties of the halogen atom. Copyright © 2001 John Wiley & Sons, Ltd.