Photo-oxygenation via electron transfer and its susceptibility to catalysis
Abstract
The photo-oxygenation of diphenylacetylene (1) is efficiently sensitized (via electron transfer) with dicyanoanthracene (Φ=ca. 0·15), but is sensitized very poorly (Φ < 0·001) with tetracyanoanthracene (TCA); catalysis by acids and nucleophiles substantially increases the quantum yield of photo-oxygenation through reactions competing with the reverse electron transfer between (TCA)–˙ and (1)+˙.