Extended radical cation of diphenyl disulfide and oxidative cyclization on a pentasil zeolite: an EPR study

Incorporation of diphenyl disulfide (1) into a pentasil zeolite (Na-ZSM5) results in the formation of the extended radical cation, 1(.+), as well as thianthrenium radical cation (2(.+)) formed by oxidative cyclization. The stabilization of 1(.+) on the internal surfaces of the zeolite is unprecedented because in solution it is converted spontaneously into 2(.+). A mechanism for the conversion of l(.+) to 2(.+) consistent with processes observed on the internal surfaces of the zeolite is proposed.