scholarly journals Helical Structure of Oligo- and Poly(m-substituted phenyl isocyanate)s Bearing an Optically Active End-Group

1998 ◽  
Vol 30 (2) ◽  
pp. 100-105 ◽  
Author(s):  
Katsuhiro Maeda ◽  
Yoshio Okamoto
Keyword(s):  
Helical Structure ◽  
Phenyl Isocyanate ◽  
Optically Active ◽  
End Group

Thermotropic Chiral Nematic Polymers as Optical Materials

1989 ◽  
Vol 175 ◽  
Author(s):  
S.H. Chen ◽  
M.L. Tsai ◽  
S.D. Jacobs
Keyword(s):  
Optical Materials ◽  
Helical Structure ◽  
Structural Features ◽  
Optically Active ◽  
Structure Property ◽  
Chiral Compound ◽  
Structure Property Relationships ◽  
Chiral Nematic ◽  
Chiral Structures ◽  
Nematic Polymers

AbstractChiral nematic copolymers based on optically active cholesterol, dihydrocholesterol, (R)-(+)- and (S)-(−)-1-phenylethylamine, and (+)- and (−)- isopinocampheol were synthesized and characterized for the investigations of thermotropic and optical properties. Although helical sense does not appear to correlate with the sign of [α]D of the precursor chiral compound as suggested by the observations of cholesteryl and dihydrocholesteryl copolymers, the inversion of chirality in the pendant group, (R)-(+)- vs (S)-(−)-1-phenylethylamine, does lead to the opposite handedness in the resultant helical structure. To better understand the structure-property relationships involving helical sense and twisting power, systematic studies of the roles played by both nematogenic and chiral structures as well as other structural features of the comonomers should be conducted.

Optically Active Poly(phenylacetylene) Film:  Simultaneous Change of Color and Helical Structure

2006 ◽  
Vol 39 (9) ◽  
pp. 3103-3105 ◽  
Author(s):  
Toshiyuki Fukushima ◽  
Kiyohiro Takachi ◽  
Kenji Tsuchihara
Keyword(s):  
Helical Structure ◽  
Optically Active ◽  
Simultaneous Change

Optically active helical poly(α,β-unsaturated ketone) from anionic polymerization of (S)-3-acrylyl-2,2′- bis(methoxymethoxy)-1,1′-binaphthyl

2014 ◽  
Vol 92 (7) ◽  
pp. 647-652
Author(s):  
Yehui Chen ◽  
Liwen Yang ◽  
Nianfa Yang ◽  
Zhusheng Yang
Keyword(s):  
Anionic Polymerization ◽  
Optical Rotation ◽  
Helical Structure ◽  
Optically Active ◽  
Unsaturated Ketone ◽  
Model Compounds ◽  
Specific Optical Rotation ◽  
G Value ◽  
Circular Dichroïsm ◽  
Structure In Solution

(S)-3-acrylyl-2,2′-bis(methoxymethoxy)-1,1′-binaphthyl (3a) was synthesized and anionically polymerized using n-BuLi as an initiator. The polymer derived from 3a had a tremendous specific optical rotation [Formula: see text] = −304.2, while that of the monomer 3a is −68.7. Poly-3a was confirmed to exist in the form of a one-handed helical structure in solution by means of comparing the specific optical rotation, the circular dichroism, and UV-vis spectra with that of 3a and the model compounds such as (S)-3-propionyl-2,2′-bis(methoxymethoxy)-1,1′-binaphthyl (3b) and (S)-3-heptanoyl-2,2′-bis(methoxymethoxy)-1,1′-binaphthyl (3c). This conclusion was also confirmed by the fact that the g value of poly-3a is about 15 times of that of the monomer 3a.

scholarly journals Chiroptical Properties of Oligomers of m-Methylphenyl Isocyanate Bearing an Optically Active End-Group

1995 ◽  
Vol 27 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Katsuhiro Maeda ◽  
Masashi Matsuda ◽  
Tamaki Nakano ◽  
Yoshio Okamoto
Keyword(s):  
Optically Active ◽  
Chiroptical Properties ◽  
End Group

The effect of P-chiral center on helical conformation of optically active N-propargylphosphonamidates

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Lihua Lu ◽  
Jiaoli Mo ◽  
Qiang Yang ◽  
Liqun Zhang ◽  
Weimin Wang ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
31P Nmr ◽  
Helical Structure ◽  
Cd Spectroscopy ◽  
Optically Active ◽  
The Other ◽  
Chiral Center ◽  
Single Peak ◽  
Helical Conformation ◽  
Molecular Weights

AbstractNovel chiral and achiral N-propargylphosphonamidate monomers [HC=CCH2NH(P=O)R1R2,where 1: R1=CH3,R2=NHC(CH3)32: R1=CH3,R2 =NHC5H93:R1=OPh,R2=NHC(CH3)3, 4:R1=R2=OPh] were synthesized by successive condensation in order to study the helical conformation properties of N-phosphonamidates. One diastereomer was successfully separated from the other in the cases of monomer 1-3(named 1a-3a) according to the single peak in the 31P NMR spectra. Polymerizations of the monomers 1-4 were carried out with (nbd)Rh+[η6-C6H5B-(C6H5)3] as catalyst in CHCl3 yielding the polymers with number-average molecular weights of 1300-22400. Poly(1a)-poly(3a) and poly(4) were characterized by UV and CD spectroscopy. Poly(1a)- poly(3a) showed an intense positive CD signal at 325 nm based on the conjugated polyacetylene backbone while poly(4) showed no peak there, indicating that the polymers had a helical structure with predominantly one-handed screw sense because of P-chiral centre sole contribution.

Optically active helical structure and magnetic interaction of poly(phenylacetylene)-based polyradicals

Polyhedron ◽  
2009 ◽  
Vol 28 (9-10) ◽  
pp. 1927-1929 ◽  
Author(s):  
Takashi Kaneko ◽  
Hiroo Katagiri ◽  
Yasuhiro Umeda ◽  
Takeshi Namikoshi ◽  
Edy Marwanta ◽  
...  
Keyword(s):  
Magnetic Interaction ◽  
Helical Structure ◽  
Optically Active
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