PREFERENTIAL CONFORMATION FOR INTRAMOLECULAR EXCIPLEX FORMATION IN CHEMILUMINESCENCE OF THE DIOXETANES, 1-(1-SUBSTITUTED-3-INDOLYL)-6-ARYL-2,5,7,8-TETRAOXABICYCLO[4.2.0]OCTANES

Abstract The title dioxetanes give in polar solvents visible chemiluminescence which is proven to be produced from the intramolecular exciplex between two aromatic substituents on the product diesters by comparison of chemiluminescence of the dioxetanes (2a–2d) and fluorescence of the corresponding diesters (3a–3d). That decomposition of the dioxetanes gives the corresponding diesters (in a singlet excited state) in a preferential conformation for the formation of intramolecular exciplex is also concluded from the above analysis as well as the examination of conformational effects on the exciplex fluorescence of the diesters, 4 and 5.