Synthesis and properties of carbamate‐ and amine‐containing poly(phenylacetylenes)

Abstract

AbstractThe 3‐ and 4‐aminophenylacetylenes protected by t‐butoxycarbonyl (t‐Boc) and 9‐fluorenylmethoxycarbonyl (Fmoc) groups (3a–6a) were synthesized and polymerized using [(nbd)RhCl]2 (1) and [(nbd)Rh+‐η6‐PhB−Ph3] (2) catalysts. The t‐Boc‐containing polymers [poly(3a) and poly(4a)] were obtained in high yield (82–91%). Among the Fmoc‐protected monomers, the para‐derivative polymerized well [poly(6a); yield = 85–94%], whereas its meta‐substituted analogue did not afford high molecular weight polymer in good yield [poly(5a); yield = 10–15%]. The use of KN(SiMe3)2 as a cocatalyst in conjunction with 1 led to a dramatic increase in the molecular weight of the polymers. The acid‐ and base‐catalyzed removal of the t‐Boc and the Fmoc groups, respectively, generated primary amine‐containing polymers [poly(3b)–poly(6b)] which cannot be obtained directly by the polymerization of the corresponding monomers. The solubility characteristics of the polymers bearing protected amino groups were quite different from those of the unprotected ones, the former being soluble in polar solvents, whereas the latter displayed poor solubility even in polar protic or highly polar aprotic solvents. The attempts to accomplish the free‐standing membrane fabrication by solution casting were successful only for poly(3a), and an augmentation in the gas permeability and CO2/N2 permselectivity was discerned in comparison with the unsubstituted poly(phenylacetylene) and poly(m‐t‐butyldimethylsiloxyphenylacetylene). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1853–1863, 2009