1 research outputs found
Linear, Single-Strand Heteroaromatic Polymers from Superacid-Catalyzed Step-Growth Polymerization of Ketones with Bisphenols
Novel,
linear, high-molecular-weight single-strand heteroaromatic
polymers and copolymers containing 9<i>H</i>-xanthene moieties
in the backbone were synthesized by metal-free superacid-catalyzed
stoichiometric and nonstoichiometric step-growth polymerizations of
carbonyl compounds bearing electron-withdrawing substituents with
bisphenols. The electrophilic aromatic substitution reactions of ketones
with phenol fragments occur exclusively in <i>ortho</i>-positions
to the hydroxy phenol group and followed by highly efficient cyclodehydration
reaction of hydroxyl-containing intermediates to give corresponding
substituted 9<i>H</i>-xanthene-2,7-diyl polymers. The polymerizations
were performed at room temperature in the Brønsted superacid
trifluoromethanesulfonic acid (CF<sub>3</sub>SO<sub>3</sub>H, TFSA)
and in a mixture of TFSA with methylene chloride and nitrobenzene