Substituent effects on the decomposition of 1,2-dioxetanes: a Hammett correlation for substituted 1,6-diaryl-2,5,7,8-tetraoxabicyclo[4.2.0]octanes

Rates of decomposition for 1,2-dioxetanes obtained from addition of singlet oxygen to substituted 2,3-diaryl-1,4-dioxenes have been found to obey a Hammett relationship with ϱ+ = −0.24 (n = 15, r = 0.92). The results are taken as support for a biradical mechanism.