Nanoparticles consisting of optically active helical polymers: Preparation via aqueous catalytic miniemulsion polymerization and the effects of particles size on their optical activity

2010 ◽  
Vol 48 (7) ◽  
pp. 1661-1668 ◽  
Author(s):  
Xiaofeng Luo ◽  
Naiwen Kang ◽  
Lei Li ◽  
Jianping Deng ◽  
Wantai Yang
Keyword(s):  
Optical Activity ◽  
Miniemulsion Polymerization ◽  
Optically Active ◽  
Helical Polymers

On the syntheses and the optical properties of optically active 2-pyrazoline compounds

1979 ◽  
Vol 57 (3) ◽  
pp. 360-366 ◽  
Author(s):  
Makoto Mukai ◽  
Takashi Miura ◽  
Masahiro Nanbu ◽  
Toshinobu Yoneda ◽  
Yohji Shindo
Keyword(s):  
Optical Properties ◽  
Optical Activity ◽  
Optically Active ◽  
Spectroscopic Techniques ◽  
Considerable Influence ◽  
Pyrazoline Ring

Optically active 2-pyrazolines were synthesized and their optical properties were studied using various spectroscopic techniques to investigate the effects of substituents at the 3 and 5 positions of the 2-pyrazoline ring on their optical activity. It was found that in the case of 5-substituted-1,3-diphenyl-2-pyrazoline derivatives, the substituent at the 5 position has considerable influence on the optical activity, whereas in 3-substituted-1,5-diphenyl-2-pyrazoline derivatives, the substituent at the 3 position has no such influence.

scholarly journals Enhanced gyrotropic birefringence and natural optical activity on electromagnon resonance in a helimagnet

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
S. Iguchi ◽  
R. Masuda ◽  
S. Seki ◽  
Y. Tokura ◽  
Y. Takahashi
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Optical Activity ◽  
Optical Rotation ◽  
Magnetoelectric Coupling ◽  
Optically Active ◽  
Crystalline Solid ◽  
Spin Order ◽  
Active Devices ◽  
Principal Axes

AbstractSpontaneous symmetry breaking in crystalline solid often produces exotic nonreciprocal phenomena. As one such example, the unconventional optical rotation with nonreciprocity, which is termed gyrotropic birefringence, is expected to emerge from the magnetoelectric coupling. However, the fundamental nature of gyrotropic birefringence remains to be examined. Here w`e demonstrate the gyrotropic birefringence enhanced by the dynamical magnetoelectric coupling on the electrically active magnon resonance, i.e. electromagnon, in a multiferroic helimagnet. The helical spin order having both polarity and chirality is found to cause the giant gyrotropic birefringence in addition to the conventional gyrotropy, i.e. natural optical activity. It is demonstrated that the optical rotation of gyrotropic birefringence can be viewed as the nonreciprocal rotation of the optical principal axes, while the crystallographic and magnetic anisotropies are intact. The independent control of the nonreciprocal linear (gyrotropic birefringence) and circular (natural optical activity) birefringence/dichroism paves a way for the optically active devices.

Optical activity and enantiomorphism

2004 ◽  
Author(s):  
Robert E. Newnham
Keyword(s):  
Optical Activity ◽  
Polarized Light ◽  
Polarization Vector ◽  
Optically Active ◽  
Crystal Thickness ◽  
Helical Structures ◽  
Active Materials ◽  
Circularly Polarized ◽  
Space Groups ◽  
Polarized Waves

When plane-polarized light enters a crystal it divides into right- and lefthanded circularly polarized waves. If the crystal possesses handedness, the two waves travel with different speeds, and are soon out of phase. On leaving the crystal, the circularly polarized waves recombine to form a plane polarized wave, but with the plane of polarization rotated through an angle αt. The crystal thickness t is in mm, and α is the optical activity coefficient expressed in degrees/mm. The polarization vector of the combined wave can be visualized as a helix, turning α ◦/mm path length in the optically-active medium. Because of the low symmetry of a helix, optical activity is not observed in many high symmetry crystals. Point groups possessing a center of symmetry are inactive. In relating α to crystal chemistry it is convenient to divide optically-active materials into two categories: Those which retain optical activity in liquid form, and those which do not. It has long been known that optically-active solutions crystallize to give optically-active solids. This follows from the fact that molecules lacking mirror or inversion symmetry can never crystallize in a pattern containing such symmetry elements. Thus one way of obtaining optically-active materials is to begin with optically-active molecules, as in Rochelle salt, tartaric acid and cane sugar. Few of these crystals are very stable, however, and the optical activity coefficients are usually small, typically 2◦/mm. The same is true of many inorganic solids, though they are seldom optically active in the liquid state. For NaClO3 and MgSO4·7H2O, α is about 3◦/mm. Quartz and selenium, however, have coefficients an order of magnitude larger, showing the importance of helical structures to optical activity. Both compounds crystallize as right- and left-handed forms in space groups P312 and P322, with helices spiraling around the trigonal screw axes. Quartz contains nearly regular SiO4 tetrahedra with Si–O distances of 1.61 Å. Levorotatory quartz belongs to space group P312 and contains right-handed helices; enantiomorphic dextrorotatory quartz crystallizes in P322. Trigonal selenium also contains helical chains.

Methacrylic polymers bearing side-chain permanent dipole azobenzene chromophores spaced from the main chain by chiral moieties, 3 a Synthesis and chiroptical properties of the homopolymer of (R)-3-methacryloyloxy-1-(4’-nitro-4-azobenzene)- pyrrolidine and of copolymers with the enantiomeric monomer (S)-3-methacryloyloxy-1-(4’-nitro-4-azobenzene)- pyrrolidine

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Luigi Angiolini ◽  
Loris Giorgini ◽  
Elisabetta Salatelli
Keyword(s):  
Radical Polymerization ◽  
Optical Activity ◽  
Main Chain ◽  
Optically Active ◽  
Side Chain ◽  
Chiroptical Properties

Abstract The optically active photochromic homopolymer deriving from radical polymerization of the monomer (R)-3-methacryloyloxy-1-(4’-nitro-4-azobenzene)- pyrrolidine, containing a chiral group of one prevailing configuration interposed between the methacrylic moiety and the photochromic azoaromatic chromophore, has been synthesized and characterized. Copolymers with the enantiomeric monomer (S)-3-methacryloyloxy-1-(4’-nitro-4-azobenzene)pyrrolidine have also been prepared in order to evaluate the effect on the overall optical activity of side chain chiral groups of opposite configuration in various ratios. The spectroscopic and chiroptical properties in solution of the polymeric derivatives have been assessed.

Dynamic optical activity induction in the N-alkyl-N′-trityl ureas and thioureas

2019 ◽  
Vol 17 (33) ◽  
pp. 7782-7793 ◽  
Author(s):  
Natalia Prusinowska ◽  
Agnieszka Czapik ◽  
Martika Wojciechowska ◽  
Marcin Kwit
Keyword(s):  
Hydrogen Bonding ◽  
Optical Activity ◽  
Optically Active ◽  
Thiourea Derivatives ◽  
Hydrogen Bonding Network ◽  
Activity Induction

Stereodynamic trityl group, utilized as a reporter of chirality, hampers hydrogen bonding network in optically active urea and thiourea derivatives.

scholarly journals The symmetrical spiro -heptanediamine and its resolution into optically active components

1936 ◽  
Vol 154 (881) ◽  
pp. 53-60 ◽  
Keyword(s):  
Carbon Atom ◽  
Optical Activity ◽  
Optically Active ◽  
Active Components ◽  
Asymmetric Carbon Atom ◽  
Molecular Configuration ◽  
Experimental Realization ◽  
Asymmetric Carbon ◽  
Acetic Acids

The experimental realization of the simplest possible types of molecular configuration which can show optical activity in the amorphous con­dition is important in connexion with stereochemical theory. Among optically active spiranes containing no asymmetric carbon atom such simple types are found in the d - and l -1-methyl- cyclo -hexylidene-4-acetic acids and the d - and 1-spiro- 5:5-dihydantoins, but no satisfactory case has hitherto been described of optical activity in substances of the constitution H —C—( CH 2 ) n —C—(CH 2 ) n —X X —C—( CH 2 ) n —C—(CH 2 ) n —H. One of the simplest conceivable examples of the latter kind should be found in the previously unknown symmetrical spiro -heptanediamine of the constitution— NH 2 —C—CH 2 —C—CH 2 —C—H H—C—CH 2 —C—CH 2 —C—NH 2 .

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