Regioisomeric Effects on the Excited State Processes of a Cyclodextrin Modified with a Lumophore

Abstract

An extraordinarily large difference in the photochemical behavior of the regioisomers is observed when the bromonaphthalene lumophore is appended to the primary or the secondary OH groups of β-cyclodextrin. In the first case when this lumophore lies outside the cavity (bottom left, oxygen of ether linkage shown in black), no phosphorescence is observed. In the second case, however, the lumophore shows bright phosphorescence even in the presence of air, which strongly suggests that it is included within the cavity (bottom right).