Anodic electropolymerization of tetrakis(2-thienyl) borate: is the boron retained in the polythiophene film?

The voltammetric study of potassium tetrakis(2-thienyl)borate 1 in CH3CN showed two irreversible two-electron steps. Similarly to its tetraphenylborate analogue, the proposed mechanism involved the decomposition of 1 followed by an electropolymerization reaction. The nature of the electrogenerated polymer was different depending on the used experimental conditions. A poly(bithiophene) film was produced over the time-scale of cyclic voltammetry whereas controlled-potential electrolysis yielded a mixture of poly(bithiophene) and a boroncontaining polymer, such as poly(dithienylboronous acid).