Evidence for the Formation of 1,2-Dioxetane as a High-Energy Intermediate and Possible Chemiexcitation Pathways in the Chemiluminescence of Lophine Peroxides

Author(s)

Boaro, Andreia ^[1] ; Reis, Roberta Albino ^[1] ; Silva, Carolina Santana ^[1] ; Melo, Diego Ulysses ^[1] ; Goncalves Costa Pinto, Alexander Garreta ^[1] ; Bartoloni, Fernando Heering ^[1]

Affiliation

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210580 Santo Andre, SP - Brazil

• Document type: Journal article
• Source: Journal of Organic Chemistry; v. 86, n. 9, p. 6633-6647, MAY 7 2021.
• Web of Science Citations: 0

Abstract

A kinetic study of the chemiluminescent (CL) reaction mechanism of lophine-derived hydroperoxides and silylperoxides induced by a base and fluoride, respectively, provided evidence for the formation of a 1,2-dioxetane as a high-energy intermediate (HEI) of this CL transformation. This was postulated using a linear Hammett relationship, consistent with the formation of negative charge on the transition state of HEI generation (rho > 1). The decomposition of this HEI leads to chemiexcitation with overall low singlet excited state formation quantum yield (Phi(s) from 1.1 to 14.5 x 10(-5) E mol(-1)); nonetheless, Phi(s) = 1.20 x 10(-3) E mol(-1) was observed with both peroxides substituted with bromine. The use of electron-donating sub-stituents increases chemiexcitation efficiency, while it also reduces the rate for both formation and decomposition of the HEI. Different possible pathways for HEI decomposition and chemiexcitation are discussed in light of literature data from the perspective of the substituent effect. This system could be explored in the future for analytical and labeling purposes or for biological oxidation through chemiexcitation. (AU)

• FAPESP's process: 12/13807-7 - New tools for the study of electron transfer reactions in PS II model systems
• Grantee: Fernando Heering Bartoloni
• Support type: Regular Research Grants
• FAPESP's process: 19/15871-3 - Light emitting arginine derivatives as tags for antimicrobial peptides
• Grantee: Andréia Boaro
• Support type: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 16/10585-4 - Mechanistic aspects regarding the induced decomposition of hydroperoxides and silylperoxides derived from lophine
• Grantee: Andréia Boaro
• Support type: Scholarships in Brazil - Doctorate