Heavy‐atom effects in the photoreactions of halogenated aromatic compounds

The photoreactions of various halogenated naphthalenes and biphenyls in methanol at 290‐310 nm are affected by addition of heavy‐atom lithium salts. The triplet decay rate appears to be increased relative to the reaction rate resulting in overall rate decrease. The effect of iodide is greater than that of added bromide while the reaction rates in the presence of chloride or in the absence of external heavy atoms proceed in the order of decreasing bond strength of the carbon‐halogen bonds.