Lophine derivatives as activators in peroxyoxalate chemiluminescence

Author(s)

Alves, J. ^[1] ; Boaro, A. ^[1] ; da Silva, J. S. ^[2] ; Ferreira, T. L. ^[2] ; Keslarek, V. B. ^[1] ; Cabral, C. A. ^[1] ; Orfao, Jr., R. B. ^[1] ; Ciscato, L. F. M. L. ^[1] ; Bartoloni, F. H. ^[1]

Affiliation

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

^[2] Univ Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Diadema, SP - Brazil

• Document type: Journal article
• Source: PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES; v. 14, n. 2, p. 320-328, 2015.
• Web of Science Citations: 8

Abstract

Lophine and four of its derivatives were used as activators (ACTs) of the chemiluminescent peroxyoxalate (PO) reaction of bis(2,4,6-trichlorophenyl) oxalate with H2O2, catalysed by imidazole. Kinetic emission assays have shown that with the tested compounds the reaction mechanism, regarding the formation of the high energy intermediate (HEI) of the PO reaction, occurs as previously seen for commonly used ACTs. A bimolecular interaction of the compounds with the HEI leads to chemiexcitation through the chemically initiated electron exchange luminescence (CIEEL) mechanism, as confirmed by a linear free-energy correlation between the relative catalytic rate constants and the oxidation potentials of the compounds. The yields of excited state formation and light emission, in the range of 10(-2)-10(-3) E mol(-1), are comparable to the ones seen with commonly used ACTs. A Hammett plot with rho = -0.90 indicates the buildup of a partial positive charge on the transition step of the catalytic process, consistent with the formation of a radical cation of the ACT, being an additional validation of the CIEEL mechanism in this system. (AU)

• FAPESP's process: 13/17332-6 - Kinetical study of a PCET process using the chemiluminescent peroxyoxalate reaction
• Grantee: Jessica Alves
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 12/02428-5 - Cyclic organic peroxides: synthesis and mechanism of reduction
• Grantee: Luiz Francisco Monteiro Leite Ciscato
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/17587-9 - Aqueous solutions of surfactants as catalysts and templates for preparation of mesoporous thin films
• Grantee: Tiago Luiz Ferreira
• Support Opportunities: Regular Research Grants
• 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 Opportunities: Regular Research Grants