Photocatalytic oxidation of selected fluorenols on TiO2 semiconductor

Photocatalytic oxidation of the title compounds 1 and 2 in nonaqueous oxygen saturated TiO2 suspension was carried out. The corresponding ketones were formed in a high yield, in addition to minor amount of the corresponding hydrocarbon and other decomposition products. Interestingly, photocatalytic oxidation of the parent fluorene (3) afforeded fluorenone under the same conditions. Also, compound 4 as an acyclic simulant gave the corresponding ketone and hydrocarbon. Furthermore, the effect of solvent polarity has been tested.An electron–hole pair generated on the irradiated TiO2 surface is suggested for the semiconductor-mediated photocatalysis. [Copyright &y& Elsevier]