Curious oxygen effect on photosensitized electron-transfer reactions of benzophenone oxime O-methyl ethers: one-way photoisomerization of an iminic double bond

Under an oxygen atmosphere, the E and Z isomer ratio of N-methoxy-4-methoxyphenyl-4′-methylphenylmethanimine (initially, [E]/[Z]=1/1) reached 4/96 upon irradiation (>360 nm) of 9,10-dicyanoanthracene (DCA) as a photosensitizer in acetonitrile.