Catalytic one-handed helix-induction and memory of amphiphilic poly(biphenylylacetylene)s in water

Racemic Monomer‐Based One‐Handed Helical Polymer Recognizes Enantiomers through Auto‐Evolution of Its Helical Handedness Excess

“…Chemie sense bias was observed in toluene. [24] By careful examination of the resolution results of rac-PEA and rac-BINOL on the (P)-h-poly(rac-3)-based CSP,w en oticed that (R)-BINOL interacts more strongly on the polymer than (S)-BINOL and PEA, resulting in alonger retention time (t 2 )with acomplete base-line separation, while the h-poly(rac-3)-based CSP did not resolve rac-PEA at all (a = 1.0) ( Figure 3b and Table 1).…”

Racemic Monomer‐Based One‐Handed Helical Polymer Recognizes Enantiomers through Auto‐Evolution of Its Helical Handedness Excess

“…We used a large amount of a chiral alcohol, ( R )‐ or ( S )‐PEA ([PEA]/[poly( rac ‐ 3 )] >1000) to completely induce a one‐handed helix in PBPAs including poly( rac ‐ 3 ) (Figure 2(i,ii)). Recently, we reported that a small amount of a hydrophobic alcohol, such as ( R )‐ or ( S )‐BINOL (0.2 equiv), is sufficient to produce a one‐handed helical PBPA derivative bearing amphiphilic achiral oligo(ethylene glycol) units at the pendants, which was possible only in water because the BINOL can be specifically encapsulated within the hydrophobic cavity of the polymer in water, whereas no helical sense bias was observed in toluene [24] . By careful examination of the resolution results of rac ‐PEA and rac ‐BINOL on the ( P )‐ h ‐poly( rac ‐ 3 )‐based CSP, we noticed that ( R )‐BINOL interacts more strongly on the polymer than ( S )‐BINOL and PEA, resulting in a longer retention time ( t 2 ) with a complete base‐line separation, while the h ‐poly( rac ‐ 3 )‐based CSP did not resolve rac ‐PEA at all ( α =1.0) (Figure 3 b and Table 1).…”

“…Forschungsartikel 4678 www.angewandte.de sense bias was observed in toluene. [24] By careful examination of the resolution results of rac-PEA and rac-BINOL on the (P)-h-poly(rac-3)-based CSP,w en oticed that (R)-BINOL interacts more strongly on the polymer than (S)-BINOL and PEA, resulting in alonger retention time (t 2 )with acomplete base-line separation, while the h-poly(rac-3)-based CSP did not resolve rac-PEA at all (a = 1.0) ( Figure 3b and Table 1).…”

Macromolecular helicity induction and static helicity memory of poly(biphenylylacetylene)s bearing aromatic pendant groups and their use as chiral stationary phases for high‐performance liquid chromatography

“…We previously reported that poly(biphenylylacetylene) (PBPA) derivatives with the appropriate substituents at the 2,2 0 ,4 0 -positions of the biphenyl pendants formed a preferred-handed helical conformation accompanied by an excess one-handed axially twisted structure of the biphenyl units through noncovalent chiral interactions with optically active guests, such as (R)-and (S)-1-phenylethanol ((R)-and (S)-PEA; Figure 1), and both the induced macromolecular helicity and pendant axial chirality were efficiently retained (memorized) after removal of the chiral inducers. [45][46][47][48][49] Taking advantage of this "macromolecular helicity induction and subsequent static helicity memory" strategy, we have succeeded in developing helical polymer-based CSPs with a static helicity memory from inherently optically inactive PBPAs composed of fully achiral 45,[50][51][52] or racemic 53 repeating monomer units, some of which showed a unique switchable enantioseparation, 45,52 that is, switching of the elution order of the enantiomers, based on the reversible macromolecular helicity control in the column. The effect of the polar functional groups introduced at the 4 0 -position of the biphenyl pendants, such as ether, ester, and carbamate groups, on the chiral recognition abilities of the PBPA-based CSPs was investigated.…”