The synthesis of poly(phenylacetylene)s with bulky chiral silyl groups and the thermal stability of their helical conformation

Abstract

The polymerization of (−)‐p‐[(tert‐butylmethylphenyl)silyl]phenylacetylene (t‐BuMePhSi*PA) and (+)‐p‐[{methyl(α‐naphthyl)phenyl}silyl]phenylacetylene (MeNpPhSi*PA) with the [(nbd)RhCl]2Et3N catalyst yielded polymers with very high molecular weights over 2 × 106 in high yields. The optical rotations of the formed poly(t‐BuMePhSi*PA) and poly(MeNpPhSi*PA) were as high as −356 and −150° (c = 0.11 g/dL in CHCl3), respectively. The circular dichroism (CD) spectrum of poly(t‐BuMePhSi*PA) in CHCl3 exhibited very large molar ellipticities ([θ]) in the UV region: [θ]max = 9.2 × 104 ° · cm2 · dmol−1 at 330 nm and −8.0 × 104 ° · cm2 · dmol−1 at 370 nm. The [θ]max values of poly(MeNpPhSi*PA) were also fairly large: [θ]max = 7.1 × 104 ° · cm2 · dmol−1 at 330 nm and −5.3 × 104 ° · cm2 · dmol−1 at 370 nm. The optical rotations of poly(t‐BuMePhSi*PA) and poly(MeNpPhSi*PA), measured in tetrahydrofuran, chloroform, and toluene solutions, were hardly dependent on temperature in the range 22–65 °C. The CD effects of these polymers hardly changed in the temperature range 28–80 °C, either. These results indicate that the helical structures of these polymers are thermally appreciably stable. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 71–77, 2001

Chiralitätsverstärkung in dynamischen supramolekularen Aggregaten

“…[11] Poly(phenylacetylene) wurden durch Yashima und Masuda und Mitarbeiter auf die Fähigkeit zur Bildung helikaler Strukturen hin untersucht. [11,[134][135][136][137][138][139] In Poly(phenylacetylenen) mit Kronenether-oder Säureseitengruppen (29 bzw. 30, Schema 17) induzierte der Zusatz von chiralen Aminosäuren bzw.…”

Chiralitätsverstärkung in dynamischen supramolekularen Aggregaten

“…[11] Poly(phenylacetylene) wurden durch Yashima und Masuda und Mitarbeiter auf die Fähigkeit zur Bildung helikaler Strukturen hin untersucht. [11,[134][135][136][137][138][139] In Poly(phenylacetylenen) mit Kronenether-oder Säureseitengruppen (29 bzw. 30, Schema 17) induzierte der Zusatz von chiralen Aminosäuren bzw.…”

Developments in synthesis, characterization, and self‐assembly of polycarbodiimide systems

“…The first synthetic helical polymer was discovered in 1955 when Natta et al successfully polymerized propylene monomers in a highly isotactic fashion . Today, the synthetic repertoire of helical polymers has grown tremendously to include poly( m ‐phenylene ethynylene), poly (phenyl acetylenes), polyisocyanates, polyisocyanides, polysilanes, poly(quinoxaline‐2,3‐diyls), and poly( cis ‐acetylenes), to name a few …”

Evidence of Entropy-Driven Bistability through 15N NMR Analysis of a Temperature- and Solvent-Induced, Chiroptical Switching Polycarbodiimide

“…18−26 Throughout this time, novel, helical macromolecular scaffolds have emerged including systems such as oligio- 27 and poly(m-phenylene ethynylenes), 28,29 polyisocyanates, 30,31 polyisocyanides, 32−34 poly-(phenyl acetylenes), 35,36 poly(quinaxoline-2,3-dials), 37,38 and polycarbodiimides 39 to name a few. Polycarbodiimides, a relatively young class of helical macromolecules, have been an intense area of interest in the Novak group since the discovery of the controlled "living" Ti(IV)-mediated polymerization of carbodiimides in 1994 due to their attractive properties such as liquid crystallinity, 40,41 high helical inversion barrier, 42 and chiroptical switching.…”

“…In addition, formation of optically active, helical macromolecules with an excess single-handed screw sense has been an evergrowing field of interest in the past two decades due to their potential uses as asymmetric polymeric catalyst supports, chiral sensors, polymeric liquid crystals, and/or stationary phases in chiral separations. − Throughout this time, novel, helical macromolecular scaffolds have emerged including systems such as oligio- and poly( m -phenylene ethynylenes), , polyisocyanates, , polyisocyanides, − poly(phenyl acetylenes), , poly(quinaxoline-2,3-dials), , and polycarbodiimides to name a few. Polycarbodiimides, a relatively young class of helical macromolecules, have been an intense area of interest in the Novak group since the discovery of the controlled “living” Ti(IV)-mediated polymerization of carbodiimides in 1994 due to their attractive properties such as liquid crystallinity, , high helical inversion barrier, and chiroptical switching. − …”

Chiralitätsverstärkung in dynamischen supramolekularen Aggregaten

“…[11] Poly(phenylacetylene) wurden durch Yashima und Masuda und Mitarbeiter auf die Fähigkeit zur Bildung helikaler Strukturen hin untersucht. [11,[134][135][136][137][138][139] In Poly(phenylacetylenen) mit Kronenether-oder Säureseitengruppen (29 bzw. 30, Schema 17) induzierte der Zusatz von chiralen Aminosäuren bzw.…”

Developments in synthesis, characterization, and self‐assembly of polycarbodiimide systems

“…The first synthetic helical polymer was discovered in 1955 when Natta et al successfully polymerized propylene monomers in a highly isotactic fashion . Today, the synthetic repertoire of helical polymers has grown tremendously to include poly( m ‐phenylene ethynylene), poly (phenyl acetylenes), polyisocyanates, polyisocyanides, polysilanes, poly(quinoxaline‐2,3‐diyls), and poly( cis ‐acetylenes), to name a few …”

Evidence of Entropy-Driven Bistability through 15N NMR Analysis of a Temperature- and Solvent-Induced, Chiroptical Switching Polycarbodiimide

“…18−26 Throughout this time, novel, helical macromolecular scaffolds have emerged including systems such as oligio- 27 and poly(m-phenylene ethynylenes), 28,29 polyisocyanates, 30,31 polyisocyanides, 32−34 poly-(phenyl acetylenes), 35,36 poly(quinaxoline-2,3-dials), 37,38 and polycarbodiimides 39 to name a few. Polycarbodiimides, a relatively young class of helical macromolecules, have been an intense area of interest in the Novak group since the discovery of the controlled "living" Ti(IV)-mediated polymerization of carbodiimides in 1994 due to their attractive properties such as liquid crystallinity, 40,41 high helical inversion barrier, 42 and chiroptical switching.…”

“…In addition, formation of optically active, helical macromolecules with an excess single-handed screw sense has been an evergrowing field of interest in the past two decades due to their potential uses as asymmetric polymeric catalyst supports, chiral sensors, polymeric liquid crystals, and/or stationary phases in chiral separations. − Throughout this time, novel, helical macromolecular scaffolds have emerged including systems such as oligio- and poly( m -phenylene ethynylenes), , polyisocyanates, , polyisocyanides, − poly(phenyl acetylenes), , poly(quinaxoline-2,3-dials), , and polycarbodiimides to name a few. Polycarbodiimides, a relatively young class of helical macromolecules, have been an intense area of interest in the Novak group since the discovery of the controlled “living” Ti(IV)-mediated polymerization of carbodiimides in 1994 due to their attractive properties such as liquid crystallinity, , high helical inversion barrier, and chiroptical switching. − …”

Chiralitätsverstärkung in dynamischen supramolekularen Aggregaten

“…[11] Poly(phenylacetylene) wurden durch Yashima und Masuda und Mitarbeiter auf die Fähigkeit zur Bildung helikaler Strukturen hin untersucht. [11,[134][135][136][137][138][139] In Poly(phenylacetylenen) mit Kronenether-oder Säureseitengruppen (29 bzw. 30, Schema 17) induzierte der Zusatz von chiralen Aminosäuren bzw.…”

Developments in synthesis, characterization, and self‐assembly of polycarbodiimide systems

“…The first synthetic helical polymer was discovered in 1955 when Natta et al successfully polymerized propylene monomers in a highly isotactic fashion . Today, the synthetic repertoire of helical polymers has grown tremendously to include poly( m ‐phenylene ethynylene), poly (phenyl acetylenes), polyisocyanates, polyisocyanides, polysilanes, poly(quinoxaline‐2,3‐diyls), and poly( cis ‐acetylenes), to name a few …”

Evidence of Entropy-Driven Bistability through 15N NMR Analysis of a Temperature- and Solvent-Induced, Chiroptical Switching Polycarbodiimide

“…18−26 Throughout this time, novel, helical macromolecular scaffolds have emerged including systems such as oligio- 27 and poly(m-phenylene ethynylenes), 28,29 polyisocyanates, 30,31 polyisocyanides, 32−34 poly-(phenyl acetylenes), 35,36 poly(quinaxoline-2,3-dials), 37,38 and polycarbodiimides 39 to name a few. Polycarbodiimides, a relatively young class of helical macromolecules, have been an intense area of interest in the Novak group since the discovery of the controlled "living" Ti(IV)-mediated polymerization of carbodiimides in 1994 due to their attractive properties such as liquid crystallinity, 40,41 high helical inversion barrier, 42 and chiroptical switching.…”

“…In addition, formation of optically active, helical macromolecules with an excess single-handed screw sense has been an evergrowing field of interest in the past two decades due to their potential uses as asymmetric polymeric catalyst supports, chiral sensors, polymeric liquid crystals, and/or stationary phases in chiral separations. − Throughout this time, novel, helical macromolecular scaffolds have emerged including systems such as oligio- and poly( m -phenylene ethynylenes), , polyisocyanates, , polyisocyanides, − poly(phenyl acetylenes), , poly(quinaxoline-2,3-dials), , and polycarbodiimides to name a few. Polycarbodiimides, a relatively young class of helical macromolecules, have been an intense area of interest in the Novak group since the discovery of the controlled “living” Ti(IV)-mediated polymerization of carbodiimides in 1994 due to their attractive properties such as liquid crystallinity, , high helical inversion barrier, and chiroptical switching. − …”