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A novel one-handed helical copoly(phenylacetylene) (CPA) bearing L -proline tripeptide pendants and a few triethoxysilyl residues was synthesized and hybridized into SiO2 porous microspheres (PMSs) during microsphere growth through the hydrolytic polycondensation of ethoxysilyl groups. Nuclear magnetic resonance and Fourier transform infrared spectroscopy results verified the successful preparation of CPA and its hybrid product using SiO2 PMSs. The chiral recognition ability of the resulting CPA with a hybridized-type chiral stationary phase (HCSP) for high-performance liquid chromatography (HPLC) was investigated, revealing its high recognition ability for selected racemates. Moreover, the HCSP showed good solvent tolerability, thus broadening the selection of suitable eluents. The separation effect of the HCSP for the racemate N,N-diphenylcyclohexane-1,2-dicarboxamide (7) improved significantly after introducing CHCl3 in the eluent, resulting in separation factors equivalent or superior to common commercially available polysaccharide-based chiral stationary phases. The proposed preparation strategy provides a new and valuable method for obtaining poly(phenylacetylene)-based HCSPs suitable for a wide range of applications and eluent conditions. [ABSTRACT FROM AUTHOR]

A series of novel phenylacetylene derivatives with two chiral centers, one of which was derived from l-phenylglycinol and the other from l- and d-alanine or l- and d-valine, were synthesized and polymerized in THF using Rh(nbd)BPh4 as a catalyst to obtain the corresponding stereoregular one-handed helical poly(phenylacetylene) derivatives (PPA-1a, PPA-1b, PPA-2a and PPA-2b). The polymers were used as chiral stationary phases (CSPs) in HPLC, and the effects of the coating solvents and configuration of the second amino acid groups on the helical conformation of the main chain and the enantioseparation were investigated. In DMF, CD intensities of PPA-1b and PPA-2b having R-configuration on the second chiral center were higher than those of PPA-1a and PPA-2a having S-configuration at the same position, indicating that PPA-1b and PPA-2b may possess more stereoregular helix senses. The chiral recognition abilities of these polymers obviously depended on the main chain helical conformation induced by different coating solvents and the chiral centers in the pendant. Some racemates were better resolved on PPA-1b and PPA-2b, especially the racemic 1-phenylprop-2-yn-1-ol (8) which could be better resolved on PPA-2b than on the well-known commercial chiral column AD-H. [ABSTRACT FROM AUTHOR]

ABSTRACT A series of novel stereoregular one-handed helical poly(phenylacetylene) derivatives ( PPA-1 and PPA-1a∼g) bearing l-phenylglycinol and its phenylcarbamate residues as pendants was synthesized for use as chiral stationary phases (CSPs) for HPLC, and their chiral recognition abilities were evaluated using 13 racemates. The phenylcarbamate residues include an unsubstituted phenyl, three chloro-substituted phenyls (3-Cl, 4-Cl, 3,5-Cl2), and three methyl-substituted phenyls (3-CH3, 4-CH3, 3,5-(CH3)2). The acidity of the phenylcarbamate N-H proton and the hydrogen bonds formed between the N-H groups of the phenylcarbamate residues were dependent on the type, position, and the number of substituents on the phenylcarbamate residues. The chiral recognition abilities of these polymers significantly depended on the dynamic helical conformation of the main chain with more or less regularly arranged pendants. The chiral recognition abilities seem to be improved by the introduction of substituents on the phenylcarbamate residues, and PPA-1d bearing the more acidic N-H groups due to the 3,5-dichloro substituents, exhibited a higher chiral recognition than the others. PPA-1d showed an efficient chiral recognition for some racemates, and baseline separation was possible for racemates 5, 11, 12, and 15. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 809-821 [ABSTRACT FROM AUTHOR]

The colorimetric detection of anionic species has been studied for α‐amino acid‐conjugated poly(phenylacetylene)s, which were prepared by the polymerization of the ethyl esters of N‐(4‐ethynylphenylsulfonyl)‐L‐alanine, L‐isoleucine, L‐valine, L‐phenylalanine, L‐aspartic acid, and L‐glutamic acid using Rh+(2,5‐norbornadiene)[(η6‐C6H5)B−(C6H5)3] as the catalyst in CHCl3. The one‐handed helical conformations of all the sulfonamide‐functionalized polymers were characterized by Cotton effects in the circular dichroism spectra. The addition of anions with a relatively high basicity, such as tetra‐n‐butylammonium acetate and fluoride, induced drastic changes in both the optical and chiroptical properties. On the other hand, anions with a relatively low basicity, such as tetra‐n‐butylammonium nitrate, azide, and bromide, had essentially no effects on the helical conformation of all the sulfonamide‐functionalized polymers. The anion signaling property of the sulfonamide‐functionalized polymers possessing α‐amino acid moieties was significantly affected by the installed residual amino acid structures. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1683–1689, 2010 [ABSTRACT FROM AUTHOR]

The design and construction of suitable sensors that can selectively recognize chemically similar substances such as aliphatic and aromatic amines remain challenging. In this work, we reported a poly(phenylacetylene) bearing two aldehyde pendants as the color indicator for discriminative identification of amines. Reversible Schiff-base reaction of the aldehyde group with the amine resulted in a conformational transition of the polyacetylene backbone from cis-cisoid to cis-transoid , which further achieved a colorimetric change. Thirteen aliphatic amines and aromatic amines had been studied. Compared with aromatic amines, aliphatic amines generally caused the polyene backbone to display perceivable colorimetric change. Steric and electronic effect played a significant role in the colorimetric response. In addition, external environment, including amine content, polymer concentration, and temperature, had influence on the sensitivity of this colorimetric indicator system. The amines-induced colorimetric variation was further demonstrated by the CIELAB color space. Moreover, the colorimetric sensor exhibited excellent reversibility and recyclability. For Table of Contents use only. [Display omitted] • Poly(phenylacetylene) was synthesized for discriminative sensing of amines. • This colorimetric system relied on the tunable cis-cisoid to cis-transoid conformational transition. • The colorimetric sensor exhibited excellent reversibility and recyclability. [ABSTRACT FROM AUTHOR]

• Poly(phenylacetylene) bearing Boc-L-valine pendants was successfully synthesized. • Various morphological assemblies were produced by tuning the volume fraction of solvent. • The chirality of supramolecular assemblies could be controlled by a heating–cooling process. A challenging aim is the precisely controlled construction of hierarchical chiral self-assembly in synthetic polymers both from the fundamental and advanced technological development perspectives. Amphiphilic polymers can be assembled into well-organized aggregates with morphological varieties, and external stimuli remarkably affect their self-assembly behavior. We designed and synthesized an amphiphilic helical poly(phenylacetylene) homopolymer containing bi-valine pendants. The hierarchical chiral self-assembly behavior of the homopolymer was realized and investigated by adding a polar solvent into the poly (L- 1) solution. Furthermore, the influences of the solvent components and temperature on the supramolecular chirality and morphologies of the ordered nanostructures were studied via circular dichroism (CD), transmission electron microscopy (TEM), and dynamic light scattering (DLS). Various morphologies such as spheres, beads-string micelles, vesicles, nanorods, flower-like, and blocky nanostructures were obtained. The polyphenylacetylene backbone was successfully endowed with chirality from L-Boc-valine pendants, and this property was further transferred and enhanced in high-ordered supramolecular self-assemblies. With the increase of polar solvent fraction, the enhanced driving force of solvophobic interaction and π-π stacking might significantly promote the aggregation of multi micelles. [ABSTRACT FROM AUTHOR]

Novel one-handed helical copoly(phenylacetylene)s bearing a small amount of 3-(triethoxysilyl)propyl residues (CPAs 1–4) were synthesized, and efficiently chemically immobilized onto silica gel by the intermolecular polycondensation of the triethoxysilyl groups. Their chiral recognition abilities were evaluated as immobilized-type chiral stationary phases (CSPs) for high performance liquid chromatography (HPLC). These immobilized-type CSPs showed different chiral recognition abilities from the corresponding coated-type CSPs, which may be ascribed to the conformational change in the copoly(phenylacetylene)s during the immobilization process according to the diffuse reflectance circular dichroism (DRCD) measurement of the copolymer. In addition, the immobilized-type CSPs showed a universal solvent tolerability, for instance, CHCl 3 -containing eluents that cannot be used with the corresponding coated-type CSPs could now be used for the immobilized-type CSPs so that the chiral recognition of i -CSP-2 for the racemic 1-(9-anthyl)-2,2,2-trifluoroethanol (5) was improved with separation factors comparable or higher than those obtained on the popular polysaccharide-based CSPs. The intermolecular polycondensation of the triethoxysilyl groups of the copoly(phenylacetylene)s is a valuable immobilization method for poly(phenylacetylene)-based CSPs. [ABSTRACT FROM AUTHOR]

Novel stereoregular helical poly(phenylacetylene)derivatives (PPA-Pheand PPA-Phg) with anamide linkage bearing l-phenylalanine and l-phenylglycineethyl ester pendants were synthesized for use as chiral stationaryphases (CSPs) in HPLC. The polymers showed different chiral recognitionabilities depending on the coating solvents. Both PPA-Pheand PPA-Phgexhibited higher chiral recognitions whencoated with CHCl3by having preferable conformations. Theirchiral recognition abilities depended on their molecular weight andoptical rotations which were influenced by the polymerization solventsand monomer concentration. PPA-Pheand PPA-Phgshowed rather different chiral recognitions, indicating that thebenzyl group of the former and the phenyl group of the latter alsoplay important roles in the chiral recognition. A few racemates werecompletely separated on PPA-Pheor PPA-Phgwith separation factors comparable or higher than those obtainedon the popular polysaccharide-based CSPs. [ABSTRACT FROM AUTHOR]