Electropolymerization of 2-aminophenylboronic acid and the use of the resulting polymer for determination of sugars and oxyacids

Resumo

Electropolymerization of aminophenylboronic acids proceeds by the mechanism typical of conducting polyaniline, if the substituent in the ring is the electron donor and its position favors the electrophilic substitution into the para position with respect to the amino group in the ring. For the same reason, the polymerization of meta-aminophenylboronic acid requires the presence of fluoride ions to transform the weak electron acceptor, boronic acid group into the electron-donating trifluoroborate anion. It is shown that electropolymerization of ortho-aminophenylboronic acid can be carried out in strongly acidic media in the absence of fluoride ions, in analogy to unsubstituted polyaniline. The conductivity of the resulting polyanilineboronic acids synthesized under optimal conditions increases upon their binding with sugars and oxyacids, which allows detecting the specific interactions only, while the nonspecific interactions lower down the polymer conductivity.