Chemiluminescence Mechanism and Quantum Yield of Synthetic Vinylpyrene Analogues of Benzopyrene-7,8-dihydrodiol

Article abstract of DOI:10.1021/ja00275a040

We have previously reported that the dioxetane chemiluminescence (CL) of the proximate carcinogenic metabolite (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzopyrene (7,8-Diol) could be produced by free singlet oxygen (1O2) in solution.We now report that the trans-1-(2-methoxyvinyl)pyrene (t-MVP) model chemical analogue, in which an ene reaction is prevented, has a CL quantum yield Φ_CL (t-MVP) of 0.0003, 180 times that of 7,8-diol.The CL emission spectrum of t-MVP was identical with the fluorescence emission spectrum of the dioxetane decomposition product, pyrene-1-carboxaldehyde (6 in Scheme II), which was isolated in 10 percent yield in ¹O2 reactions.The solvent dependencies of Φ_CL t-MVP of dioxetanes parallel the fluorescence quantum yield (Φ_Fluor) of 6 and the CL yield from dioxetanes of 7,8-Diol in these same solvents.This dioxetane CL of the t-MVP analogue supports the originally proposed dioxetane CL mechanism of 7,8-Diol.The limiting factor in 7,8-Diol CL appears to be the low chemical yield for formation of the 9,10-dioxetane.