9,10-Dicyanoanthracene-photosensitized elimination of 1,1'-binaphthalene from dinaphthyl methylphosphonate and trinaphthyl phosphate through the termolecular interaction in the singlet excited state

Article abstract of DOI:10.1246/bcsj.72.2103

9,10-Dicyanoanthracene (DCA) photosensitized intramolecular binaphthalene elimination of dinaphthyl methylphosphonates and trinaphthyl phosphates occurred through an exciplex between the singlet excited DCA (¹DCA*) and the naphthyl group of dinaphthyl methylphosphonate and trinaphthyl phosphates in tetrahydrofuran, 1,4-dioxane, and benzene. Diethyl mononaphthyl phosphates also formed an exciplex with ¹DCA*, while no reaction occurred. The binaphthalene elimination occurs via the intramolecular quenching of the exciplex by the second naphthyl group of dinaphthyl methylphosphonate or trinaphthyl phosphate, while the exciplex between the mononaphthyl phosphate and ¹DCA* decays to give the starting compounds. The lifetime of the exciplex between the trinaphthyl phosphate and ¹DCA* was shorter than that between the mononaphthyl phosphate and ¹DCA*. The termolecular interaction (teraromatic groups interaction) of ¹DCA* and two naphthyl groups of dinaphthyl methylphosphonate or trinaphthyl phosphate is suggested by the emission observation of the termolecular interaction of two naphthyl groups of trinaphthyl phosphate and 1,4-dicyanobenzene in the singlet excited state during the quenching of the intramolecular excimer of dinaphthyl methylphosphonate or trinaphthyl phosphates by 1,4-dicyanobenzene. The O-P(O)-O spacer is necessary for the binaphthalene elimination during the termolecular interaction in the singlet excited state.