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LACK OF HEAVY ATOM EFFECT ON THE ACTIVATION PARAMETERS OF BROMINE SUBSTITUTED 1,2‐DIOXETANES *
Author(s) -
Adam Waldemar,
Sakanishi Katsumasa
Publication year - 1979
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1979.tb07112.x
Subject(s) - dioxetane , diradical , bromine , chemistry , photochemistry , decomposition , thermal decomposition , atom (system on chip) , kinetic energy , medicinal chemistry , organic chemistry , singlet state , chemiluminescence , excited state , atomic physics , physics , quantum mechanics , computer science , embedded system
— The continuous temperature variation kinetic method was applied to the direct chemilu‐minescence of tetramethyl‐1,2‐dioxetane ( 1a ), 3‐bromomethyl‐3,4,4‐trimethyl‐1,2‐dioxetane ( 1b ), 3,3–bis‐ (bromomethyl‐4,4–dimethyl‐1,2–dioxetane ( 1c ) and 3,4–bis(bromomethyl)‐3,4–dimethyl‐1,2‐dioxetane ( 1d ). The activation energies (Ea) were found to be 27.6 ± 0.1, 28.4 ± 0.1, 28.0 ± 0.2, and 27.6 ± 0.2 kcal/mol, respectively. These results show that the heavy atom effect by the bromine substituents on the activation energies is negligible, confirming previous conclusions that a diradical mechanism operates in the thermal decomposition of these dioxetanes.