Poly-n-hexyl

We also reported an intriguing chiral termini effect in rodlike poly(n-hexyl-(2-methylpropyl)silane) with (5)-2-me(hylbu(yl termini (15).28g Although the value of gabs is only +1 x 10-5, which indicates a very weak preferential screw sense in 15, it is noted that the preferential screw sense of 15 was opposite to that of 4, bearing the same (5)-2-me(hylbutyl side groups.28d,28f,28k... 

Figure 4.21 (a) CD spectra and (b) plot of CD intensities of poly n-hexyl(p-(J>)-2-methyl-... 

Figure 4.25 Change of CD intensity of poly n-hexyl(p-(J>)-2-methylbutoxyphenyl)silane (40) aggregates prepared by methods I and II at (a) 60%/40% and (b) 55%/45% THF/methanol volume ratios in multiple thermal cycles of heating to 50°C and cooling to —10°C.

A few synthetic helical polymers are known to act as chiral selectors.7a,918d l8k i9d i9h ancj are widely used as chiral stationary phases (CSP) in gas or liquid chromatography.73,53 Recently, it has been reported that the preference of one helical sense in isotropic solution can be induced by some interaction between optically inactive polymers and chiral solvents/additives. Examples of this include poly(n-hexyl isocyanate)18d l8k and poly(phenylacetylene)s bearing functional group.19d 19h The polysilane derivatives also show chiral recognition ability in solution at room temperature. Poly(methyl-ft-pinanylsilane) includes two chiral centers per bulky hydrophobic pinanyl side group28 and... 

Figure 4.27 (a) CD and UV spectra of poly n-hexyl(p- -propoxyphenyl)silane (41) aggregates in toluene/(5> (a solid line) or (R)-2-butanol (b dotted line)/methanol mixtures at 20°C and (.b) plot of CD intensities at 354 nm of the polysilane aggregates in toluene/various ratio of (5)/(i )-2-butanol/methanol mixtures at 20°C. 

A series of optically active poly alkyl(phenyl)silane derivative copolymers with different chiral molar composition 44 and 45, are shown in Chart 4.7, along with homopolymers poly(methyl(phenyl)silane) (42) and poly(n-hexyl(m-tolyl)silane) (43). 

Itou et al. [60] determined 0II/0C for isotropic solutions of poly(n-hexyl isocyanate) (PHIC) and dichloromethane (DCM) from sedimentation equilibrium data on narrow distribution PHIC samples. Figure 3 shows their results, where the ordinate Mw(0II/0c) represents the osmotic pressure increment on the molar concentration scale. 

Fig. 2 Comparison of UV absorption spectra of four optically active polysilanes in THF at 30 °C Poly methyl-(S)-2-methylbutylsilane (1, a of 0.59), poly n-hexyl-(S)-4-methylpentylsilane (2, a of 0.75), poly n-hexyl-(S)-3-methylpentylsilane (3, a of 0.92), poly n-hexyl-(S)-2-methyl-butylsilane (4-S, a of 1.25)...

Figure 7a compares the UV and CD spectra of homopolymer 4-S and copolymer 10 with 10 mol % of (S)-2-methylbutyl and 90 mol % of 2-methyl-propyl side groups in isooctane at - 5 °C. The UV-CD spectra of 10 are almost identical to those of 4-S, with the CD signal profile matching the corresponding UV absorption, except for their 7,max values. As expected, the UV and CD spectra of copolymer 11 bearing (JR)-2-methylbutyl side groups reveal almost identical features to those in 4-R, the corresponding antipode of 4-S, except for the sign of the CD band, as shown in Fig. 9b. For comparison, UV and CD spectra of poly(n-hexyl-2-methylpropylsilane) (12) in isooctane at - 5 °C are displayed in Fig. 7c. It is evident that UV spectral characteristics (Amax,...

Fig. 20 a CD spectra and b CD intensities of poly n-hexyl(p-(S)-2-methylbutoxyphenyl)-silane (26) aggregates at different THF/methanol volume fractions at 20 °C... 

Fig. 26 CD intensities of poly n-hexyl(p-n-propoxyphenyl)silane (27) aggregates in toluene/series of (S)-primary chiral alkyl alcohols/methanol mixtures at 20 °C. For comparison, the CD intensity with (S)-2-butanol is inserted...

We have been interested in studying molecular dynamics of polymer chains and alkyl groups anchored at one end, particularly n-alkyl glycol and glycerol derivatives, poly(n-butyl acrylate) (PBA), poly(n-butyl methacrylate) (PBMA), and poly(n-hexyl meth-... 

Decanediol (DD) and 1,2-hexadecanediol (HDD) were synthesized from their respective alkenes(19). 1,2,3-decanetriols (DT) were prepared by a procedure described in the literature (20). Poly(n-butyl methacrylate)(PBMA) was obtained from Polyscience as high molecular weight material. Solutions were made without further purification using toluene-dg as a solvent. Poly(n-hexyl methacrylate)(PHMA) and Poly (ri-butyl acrylate)(PBA) were purchased as toluene solutions (25 wt%) from Aldrich Chemical Co. 

C 6 Chinai, S. N. Poly-n-hexyl methacrylate. IV. Dilute solution properties by viscosity and light scattering. J. Polymer Sci. 25, 413 (1957). 

A more remarkable and dramatic change in the conformation of helical polymers upon photoirradiation has been observed for the azobenzene-modified poly isocyanates. Polyisocyanates are typical dynamic helical polymers [59,60]. Even the optically inactive poly(n-hexyl isocyanate) (20), which is devoid of stereogenic centers, exists as an equal mixture of right- and left-handed helical conformations. Equilibrium exists in solution between both helices separated by... 

Few other sets of viscosities exist for polymeric nematics. Yang and Shine (1993) obtained three of the Leslie viscosities for monodomains of poly(n-hexyl isocyanate) (PHIC) from rheological measurements in the presence of an electric field, and they obtained values reasonably consistent with the predictions of the Kuzuu-Doi expressions. From monodomains of the polyion PBZT, poly(l,4-phenylene-2,6-benzobisthiazole) in methane sulfonic acid, some of the Leslie-Ericksen parameters have been extracted via light-scattering and magnetic-field-reorientation studies (Berry 198S Srinivasarao and... 

Dynamic Mechanical Properties of Poly-n-Hexyl Methacrylate. J. CoUoid Sci 12, 389- 399 (1957). 

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