Magnetic isotope effects in biradicals: Substantial 13C enrichment and a novel mechanistic probe

Abstract Photolysis of 2,n-diphenylcycloalkanones (n-membered ring, n = 10, 11, 12, 15) produces products that are significantly enriched in 13 C. The enrichments are different for each product, and this allows assignment of the dynamic pathways through which each product is formed.