66762-83-2Relevant academic research and scientific papers
Experimental evidence of the occurrence of intramolecular electron transfer in catalyzed 1,2-dioxetane decomposition
Ciscato, Luiz Francisco M. L.,Bartoloni, Fernando H.,Weiss, Dieter,Beckert, Rainer,Baader, Wilhelm J.
experimental part, p. 6574 - 6580 (2010/11/17)
The activation parameters for the thermal decomposition of 13 acridinium-substituted 1,2-dioxetanes, bearing an aromatic moiety, were determined and their chemiluminescence emission quantum yields estimated, utilizing in situ photosensitized 1,2-dioxetane generation and observation of its thermal decomposition kinetics, without isolation of these highly unstable cyclic peroxides. Decomposition rate constants show linear free-energy correlation for electron-withdrawing substituents, with a Hammett reaction constant of Φ = 1.3 ± 0.1, indicating the occurrence of an intramolecular electron transfer from the acridinium moiety to the 1,2-dioxetane ring, as postulated by the intramolecular chemically initiated electron exchange luminescence (CIEEL) mechanism. Emission quantum yield behavior can also be rationalized on the basis of the intramolecular CIEEL mechanism, additionally evidencing its occurrence in this transformation. Both relations constitute the first experimental evidence for the occurrence of the postulated intramolecular electron transfer in the catalyzed and induced decomposition of properly substituted 1,2-dioxetanes.
Structural Effects on the Intramolecular Electron Transfer Induced Decomposition of a Series of 1,2-Dioxetanes Derived from 9-Alkylidene-10-methylacridans
Lee, Chris,Singer, Lawrence A.
, p. 3823 - 3829 (2007/10/02)
A series of 1,2-dioxetanes derived from 9-alkylidene-10-methylacridans, Ar=CR1R2, were studied: 5, R1=R2=phenyl; 1, R1=phenyl, R2=H; 6, R1=R2=H.Thermal decomposition of these dioxetanes in the temperature range -30 to +35 deg C is accompanied by chemiluminescence (CL), N-methylacridone(NMA) fluorescence, with representative room temperature ΦCL's of 0.11, 0.04, and ca.10-5 and room temperature lifetimes of ca.2000, ca.60, and ca.6 s, for 5, 1, and 6, respectively.The only triplet states produced in these system is by 1NMA* 3NMA* as indicated by triplet counting experiments.The CL from decomposition of 1 is subject to off/on switching by successive addition of acetic acid and triethylamine.The proposed mechanism involves intramolecular electron transfer (N to peroxide bond) induced decomposition, via a boat conformation, to a dipolar intermediate that partitions between chemiexcitation and nonchemiexcitation pathways.The related low CL levels from decomposition of 1 when prepared by triphenyl phosphite ozonide oxygenation, and the CL enhancement with added triethylamine, are explained.
