Advanced chemistry of dioxetane-based chemiluminescent substrates originating from bioluminescence

A class of high-energy molecules, the 1,2-dioxetanes, have received a great deal of attention because of their unique ability to decompose thermally into electronically excited carbonyl products. Their chemistry originates from studies on molecular mechanisms of bioluminescence and has a history of over 30 years. However, the luminescent efficiency of the dioxetanes could hardly be compared with that for bioluminescence until a dioxetane bearing an easily oxidized aryl group was found to afford efficient chemiluminescence by the intramolecular chemically initiated electron exchange luminescence (CIEEL) mechanism. Nowadays, the CIEEL-type dioxetanes are being applied to modem biochemical and biomedical analyses. In this review, the advanced chemistry of the CIEEL-type dioxetanes as highly efficient chemiluminescent substrates is described, focusing on their molecular design and synthesis. Singlet chetmexcitation processes for the intramolecular CIEEL decay of dioxetanes and triplet chemiexcitation processes for the thermolysis of dioxetanes are also discussed. (C) 2004 Japanese Photochemistry Association. Published by Elsevier B.V. All rights reserved.