Abstract
The ground-state conformations, spectroscopy, and photochemistry of 2-vinylbiphenyl and three of its vinyl-substituted derivatives have been investigated. The ground state exists as a mixture of syn and anti conformers in which the vinyl group is directed either toward or away from the unsubstituted phenyl ring. Both conformers are highly non-planar, having large phenyl-phenyl and phenyl-vinyl dihedral angles. The vinylbiphenyls are found to undergo conformer-specific photochemistry. The syn rotamers are non-fluorescent and undergo rapid and efficient cyclization to 8a,9-dihydrophenanthrene intermediates, which undergo rapid thermal sigmatropic rearrangements to yield 9,10-dihydrophenanthrenes. The intermediates have been generated at 77 K and detected by absorption spectroscopy. The singlet states of the anti rotamers are fluorescent, and undergo competing intersystem crossing and activated C=C torsion. The torsional barriers are of the order of those for styrenes with similar vinyl substituents.
Original language | English (US) |
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Pages (from-to) | 1059-1066 |
Number of pages | 8 |
Journal | Photochemical and Photobiological Sciences |
Volume | 2 |
Issue number | 11 |
DOIs | |
State | Published - Nov 2003 |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry