Intramolecular Photocycloaddition of (E)-3-(4-Methoxyphenyl)-3-pentenyl 6-Cyano-9-phenanthrenecarboxylate. Temperature and Solvent Effects
(E)-3-(4-Methoxyphenyl)-3-pentenyl 6-cyano-9-phenanthrenecarboxylate as well as the corresponding 9-phenanthrenecarboxylate exhibited exciplex emission and gave photocycloadducts of the double bond with the phenanthrene 9,10 bond (a cyclobutane) and with the ester carbonyl group (an oxetane).The involvement of plural exciplex intermediates for these phenomena was proposed on the basis of the temperature and solvent dependence of quantum efficiencies of fluorescence and cycloadditons as well as of the effects of quenchers of exciplex intermediates.