Helical polymers based on intramolecularly hydrogen-bonded aromatic polyamides

Abstract

Inspired by arylamide-based oligomeric foldermers that are stabilized by intramolecular hydrogen bonding, a series of polyamides with intramolecular hydrogen-bonding motifs were synthesized via polycondensation reactions. These polymers can fold into helical conformation different from their linear control. The chirality of helical conformation can further be tuned via acid-base complexation using chiral residues.

Chiral anion-triggered helical poly(ionic liquids)

“…The observation of cotton effects in CD spectrum suggest the helical conformation of CPILs in aqueous which is further supported by the previous literature reports. 24,29,60,63 In our studies, we have observed the positive and negative cotton effects in the CD spectra of CPILs. The CPILs possessing L-and D-amino acids as counter anions show completely opposite CD signals as shown in Figure 2.…”

“…This strong cotton effects in the CPILs CD spectra evidences the chiral orientation of polymer chain in a helical confirmation as suggested by previous reports. 24,29,60,63 The first and second positive cotton effects in CD spectrum of CPILs were observed at 213 and 195 nm, whereas the first and second negative cotton effects in CD spectrum of CPILs were observed at 214 and 196 nm, respectively. The UV CD studies clearly suggest the helicity in these chiral PILs.…”

“…14,23 There are more reports on polymers, oligomers and some organic molecules with single helix morphology. [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] But the formations of double helices from synthetic molecules are relatively rare when compared with single helix formation. The different approaches were reported in the literature about double helix formation, the most widely known approach is the metal directed self-assembly called as "helicates".…”

Functional Aromatic Polyamides

“…Trying to mimic nature, many researches have been directed into developing artificial helical polymers. Lu et al [158] synthesized a series of polyamides with intramolecular hydrogen-bonding motifs that can fold into helical conformation (Scheme 42, P69). For that purpose, they prepared polymer P69-1 from methoxy-substituted m-amino benzoic acid and compared it with an analogous polymer from m-amino benzoic acid, with a similar structure but unable to form multiply centered intramolecular H-bonds.…”

Synthesis and liquid crystalline behavior of bulky poly(methacrylamide)s

“…Synthetic polymers often adopt secondary structures guided by the make‐up of their monomer units and pendant side‐chains . Poly(methylmethacrylate)s containing bulky pendant units, synthesized mainly via anionic polymerization or uncontrolled radical polymerization, are known to form rigid, helical structures .…”