Photolysis of diarylcadmium compounds in benzene

Photochemical decomposition of selected diarylcadmium compounds in dilute benzene solutions was investigated. This reaction was found to involve initial cleavage of the aryl–cadmium bonds followed by coupling of the aryl radicals to give symmetrical biaryls in good yields. Arylation products were obtained in only 5–25% yields, in contrast with the photolysis of iodoaromatic compounds in benzene which gives arylation products in high yields. Diarylcadmium compounds derived from polynuclear aromatic compounds, e.g. di(p-biphenyl)cadmium and di(α-naphthyl)cadmium gave, under the same conditions, predominantly hydrogen transfer products. In carbon tetrachloride, photolysis of diarylcadmium compounds gave chloroarenes in high yields.