Photooxygenation of cyclohexane by O2 occurs efficiently under visible-light irradiation of an O2-saturated acetonitrile solution containing 9-mesityl-10-methylacridinium ions (Acr+–Mes) and HCl to yield cyclohexanone, cyclohexanol and hydrogen peroxide. The photocatalytic reaction is initiated by electron transfer from Cl− to the mesitylene radical cation moiety.
