Fullerene-catalyzed reduction of azo derivatives in water under UV irradiation

Metal-free fullerene (C(60)) was found to be an effective catalyst for the reduction of azo groups in basic aqueous solution under UV irradiation in the presence of NaBH(4). Use of NaBH(4) by itself is not sufficient to reduce the azo dyes without the assistance of a metal catalyst such as Pd and Ag. Experimental and theoretical results suggest that C(60) catalyzes this reaction by using its vacant orbital to accept the electron in the bonding orbital of azo dyes, which leads to the activation of the N=N bond. UV irradiation increases the ability of C(60) to interact with electron-donor moieties in azo dyes.