Isomerization of t-stilbene in alcohols

Recent Developments in Ultrafast Time-Resolved Vibrational Spectroscopy of Electronically Excited States

“…The experimentally determined branching ratio in alkanes is 3.1 x 10 -3 , which can be rewritten in the form of the exponential factor at T = 300 K with the potential barrier ΔE of 3.4 kcal mol -1 . This value agrees excellently with the ΔE value (3.5 kcal mol -1 ) determined from fluorescence lifetime [12]. There is a certain formalistic similarity between Eq.…”

“…5, where we assume the participation of the second excited singlet state Z which is likely to be zwitter ionic [12]. By collision with the solvent (more generally, by the fluctuation of the solvent field), the Z state suddenly becomes lower in energy than the Si state and the double-bond frequency jumps to the single-bond frequency.…”

Donor-Acceptor Conjugated Linear Polyenes: A Study of Excited State Intramolecular Charge Transfer, Photoisomerization and Fluorescence Probe Properties

“…Substituent can raise or lower the torsional energy barrier and thus the Φ f as well as photoisomerization quantum yield (Φ t-c ) are altered. It is also found that stilbene containing heavy atom/groups (e.g., halogen, nitro) on one of its phenyl rings undergoes photoisomerization from its triplet excited state rather than singlet excited state [65][66][67].…”

“…The photoisomerization in linear polyenes is highly regioselective and is much influenced by substitutent, polarity of the medium [28][29][30][31][32][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73] and dipolar nature of the excited state [74][75][76][77][78]. Various mechanistic models have been proposed to understand the photoisomerization process of retinyl and related polyenes.…”

Stilbene Photoisomerization

“…While in the case of 4-nitrostilbene, the triplet pathway dominates the singlet route, and in the case of alkyl/alkoxy substituents the singlet mechanism is prevalent, and the isomerization of 4-bromostilbene tends to proceed by a combination of these two processes [55][56][57][58][59]. While in the case of 4-nitrostilbene, the triplet pathway dominates the singlet route, and in the case of alkyl/alkoxy substituents the singlet mechanism is prevalent, and the isomerization of 4-bromostilbene tends to proceed by a combination of these two processes [55][56][57][58][59].…”