Photocatalytic Transformation of Guanine Using Colloidal CdS Nanoparticles

Investigations into the photoinduced reactions of deoxyribonucleic acid (DNA) bases are important for human health. Herein, we have synthesized colloidal CdS nanoparticles by a method reported in the literature. The mean particle diameter of the semiconductor was about 55 nm. The colloidal CdS particles were used as a photocatalyst to investigate the organic transformation of guanine (2-amino-6-oxopurine). The products of the semiconductor-induced reaction were analyzed by liquid chromatography-mass chromatography (LC-MS) measurements. The solitary product of the photocatalytic reaction of guanine was revealed as 2,5-diamino-4H-imidazol-4-one. The likely reaction pathway for the formation of the product has been presented. To our understanding, the present work is the first account on the mechanistic aspects of the semiconductor-induced photocatalytic reaction of guanine.