Ionic photodissociation in arylallyl acetates.
We have synthesized several 3-arylallyl acetates 1, 2, 3, 5 and 6, and E-3-(1-naphthyl)-2-propene-1-ol 4 for studying ionic photodissociation. Compounds 1, 2 and 3 underwent an efficient ionic photodissociation in polar solvents like acetonitrile and methanol leading to the formation of rearranged acetate and methyl ether products, as well as undergoing an E-Z isomerization. The arylallyl alcohol 4 and the two arylallyl acetates 5 and 6 did not undergo ionic photodissociation. Quantum yields of product formation, quantum yields of fluorescence, solvent polarity effects and triplet-sensitization studies indicated that a highly polarized excited singlet state is responsible for the ionic photodissociation. Both the singlet- and triplet-excited states are effective in displaying E-Z isomerization in 1, 2, 3 and 4. Compounds 5 and 6 are highly fluorescent, and the fluorescence may be the excited state deactivation pathway along with internal conversion.
Organic Chemistry Division II, Indian Institute of Chemical Technology, Hyderabad.
G Venugopal
GV
Rao
M Janaki Ram
MJ
Reddy
K
K
Srinivas
Maruthi Janaki Ram
MJ
Reddy
K Mani
KM
Bushan
V Jayathirtha
VJ
Rao