A strong emissive chemically induced dynamic nuclear polarization signal of 1,4-benzoquinone (Q) was observed when a mixture of Q, 1,2,3,4-tetrahydro-1:4-methano-9,10-dimethoxyanthracene (D) and cyclohexylidenepropanedinitrile (A) was UV irradiated in situ in acetonitriled 3 . Also observed was the NMR line broadening of D. The results are explained by the quinone-mediated photoelectron transfer from D to A.
