Mechanisms of Organic Chemiluminescence

• Grant number: 23/06417-2
• Support Opportunities: Regular Research Grants
• Duration: November 01, 2023 - October 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Joséf Wilhelm Baader
• Grantee: Joséf Wilhelm Baader
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Chemiluminescent and bioluminescent processes are being widely used in various analytical and bioanalytical assays, including applications for in vivo imaging. The decomposition of four-membered cyclic peroxides, namely 1,2-dioxetanes and 1,2-dioxetanones is involved in many chemiluminescent transformations. The mechanism of formation of excited states involves, in many cases, electron transfer processes from an activator to a cyclic peroxide, which can occur in an intra or intermolecular way, and usually the intermolecular processes are of low efficiency, however, the intramolecular transformations can be highly efficient. On the other hand, the peroxyoxalate reaction involves intermolecular electron transfer processes, but has high chemiluminescence efficiency. This research project proposes the study of the mechanisms of the following chemiluminescent transformations: catalyzed decomposition of cyclic peroxides (involving intermolecular electron transfer, occurring with low efficiency); induced decomposition of phenoxy-substituted 1,2-dioxetanes (involving intramolecular electron transfer, occurring with high efficiency); peroxyoxalate reaction (involving intermolecular electron transfer, but has high efficiency). The effect of the medium on the quantum yields of chemiexcitation in these systems will be studied. In addition, the effect of the presence of water on the efficiency of the peroxyoxalate reaction will specifically be studied and efforts will be made to create highly efficient peroxyoxalate systems with reagents of low environmental toxicity. It is expected to obtain, from these studies, information on the factors that determine the chemiexcitation quantum yields of chemiluminescent transformations and, eventually, to extrapolate this information to bioluminescent transformations. With this mechanistic information the rational design of analytical applications involving bio and chemiluminescent transformations can be possible. (AU)