SEMICONDUCTOR PHOTOCATALYSIS - QUANTIZED CDS-CATALYZED PHOTOFORMATION OF 1-BENZYL-1,4-DIHYDRONICOTINAMIDE (BNAH) FROM 1-BENZYLNICOTINAMIDE (BNA+)

Freshly pepared CdS suspensions (CdS-0) consisting of quantised particles and their loose aggregates catalyse the photoreduction of 1-benzylnicotinamide (BNA+) in water under visible-light irradiation using triethylamine (TEA) as a sacrificial electron donor. Isomeric dimers of (BNA)2 are also found as one-electron reduction products from BNA+, whereas the photocatalysis of commercially available CdS powder (Aldrich, Cds-Ald) leads only to the formation of the dimers. The formation of cadmium metal (Cd(o)) on the lattice Is indispensable for the photoformation of BNAH, suggesting that the eventual two-electron reduction on irradiation of CdS-0 with TEA in water, should proceed through hydrogen atom transfer from Cd(o)-H formed on the lattice of CdS-0.