Photopolymerization of Pyrrole Initiated by the Ferrocene- and Iron-Arene Salts-Chlorinated Solvents Complexes

Ferrocene- and iron-arene salts can photoinitiate polymerization of pyrrole in the presence of halogenated solvents, such as CH 2 CH 2 Cl 2 , CHCl 3 , and CCl 4 , when irradiated with UV light (254 nm). The polypyrroles obtained are black colloidal powders and have low conductivity in the range of 10 −5 S cm −1 and rather poor electrochemical properties, which can be the result of loss of conjugation by halogenation. Polypyrrole samples contain both covalently bounded CCl 3 groups (from CCl 4 ) and ionic FeCl − 4 . A mechanism of photoinitiated polymerization of pyrrole has been proposed.