We have previously reported that the dioxetane chemiluminescence (CL) of the proximate carcinogenic metabolite (±)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (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 ϕCL(t-MVP) of 0.003, 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% yield in 1O2 reactions. The solvent dependencies of ϕCL t-MVP of dioxetanes parallel the fluorescence quantum yield (ϕFluor) 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.
ASJC Scopus subject areas
- Colloid and Surface Chemistry