Charge-Transfer Quenching of Excited Ketones by Selenides

Diphenyl selenide (kq = 2.5 × 10^9 mol^-1 dm^3 s^-1) and selenoxide (2.5 × 10^8) quenched the Type II reaction of butyrophenone through a charge-transfer process more efficiently than the corresponding sulfide (1.5 × 10^8) and sulfoxide. The irradiation of 2-(benzylseleno)ethyl benzoylacetate gave bis[2-(benzoylacetoxy)ethyl] diselenide and 1,2-diphenylethane.