143798-76-9Relevant articles and documents
Thermolysis of 3-Methyl-3-(o-aryl)-1,2-dioxetanes: Activation Parameters and Chemiexcitation Yields
Baumstark, Alfons L.,Parker, Alesia N.
, p. 791 - 794 (2007/10/02)
3-Methyl-3-(o-tolyl)-1,2-dioxetane 1 and 3-methyl-4-(o-bromophenyl)-1,2-dioxetane 2 were synthesized in low yield by the β-bromo hydroperoxide method.The activation parameters were determined by the chemiluminescence method (for 1 ΔG(excit.) = 24.7 +/- 0.3 kcal/mol, ΔH(excit.) = 25.4, ΔS(excit.) = +1.9 e.u., k60 = 3.4 * 10-4s-1; for 2 ΔG(excit.) = 24.7 +/- 0.4 kcal/mol, ΔH(excit.) = 24.7, ΔS(excit.) = 0.0 e.u., k60 = 4.1 * 10-4s-1).Thermolysis of 1-2 directly produced high yields of excited triplets as expected for this type of dioxetane T) for 1 0.03; for 2 0.02; the ΦT/ΦS ratios were estimated to be approximately 200 for both compounds>.The effect of ortho-aryl substituents was inconsistent with electronic effects.The ortho substitution in 1-2 resulted in a marked increase in stability of the dioxetanes.The results are discussed in relation to a diradical-like mechanism.
