CXXXIII.—The relation between unsaturation and optical activity. Part III. Optically active salts of acids containing adjacent unsaturated groups

1908 ◽  
Vol 93 (0) ◽  
pp. 1388-1395 ◽  
Author(s):  
Thomas Percy Hilditch
Keyword(s):  
Optical Activity ◽  
Optically Active

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 .

Studies of the optically active compounds of Anacardiaceae exudates. II. The action of Alkali on the long-chain alicyclic Keto Alcohol of Tigaso Oil

1958 ◽  
Vol 11 (1) ◽  
pp. 64 ◽  
Author(s):  
LK Dalton ◽  
JA Lamberton
Keyword(s):  
Optical Activity ◽  
Active Compound ◽  
Optical Rotation ◽  
Large Change ◽  
Optically Active ◽  
Bicyclic Compound ◽  
Compound I ◽  
Alcoholic Alkali ◽  
Rapid Reaction ◽  
Long Chain

In cold alcoholic alkali the optically active compound I from Tigaso oil undergoes a rapid reaction which involves loss of its conjugated carbonyl system, and a large change, with inversion, of its optical rotation. The reaction is interpreted as a cyclization and the product is provisionally formulated as a bicyclononane derivative IIa. In hot alcoholic alkali, IIa is not the final product ; the bicyclic compound undergoes further reaction to give a mixture in which the unsaturated monocyclic triketone VII (R=C16H31) appears to predominate, but which probably consists of a mixture of VII and VIII (R=C16H31). These can be hydrogenated to a mixture of saturated monocyclic triketones VII and VIII (R =C16H33). The same hydrogenated triketones are obtained if IIa is first hydrogenated and then heated with alcoholic alkali. These triketones are optically active and by oxidation with hypobromite, or with permanganate and then hypobromite, yield bromoform and the chemically homogeneous tribasic acid IX, which still retains optical activity. The isolation of the saturated hydroxydiketone IIb in 4 per cent, yield from hydrogenated Tigaso oil suggests that 11% is present to that extent in the original oil.

Ellipsometric Characterization for Multilayers Containing Magneto-Optic TbFeCo Films

1987 ◽  
Vol 103 ◽  
Author(s):  
M. Ruane ◽  
A. Jain
Keyword(s):  
Optical Activity ◽  
Optical Signal ◽  
Optically Active ◽  
Index Of Refraction ◽  
Dielectric Tensor ◽  
Angle Of Incidence ◽  
Multilayered Structures ◽  
Kerr Rotation ◽  
Ellipsometric Characterization ◽  
Sputter Deposited

ABSTRACTMultilayered structures containing sputter-deposited films of amorphous TbFeCo can exhibit magneto-optical Kerr rotation and are leading candidates for erasable optical storage media. Ellipsometric characterization of optically active multilayered media is desirable during media development, testing and production, but traditional ellipsometry does not account for the presence of optical activity. A novel ellipsometer is described that can characterize both the dielectric overcoat and the optically active layers. Reflectivity measurements are collected for different incident angles and polarizations using a differential detector while the magnetic reversibility of the active film layer is exploited to enhance the magneto-optical signal from the TbFeCo. A multilayer film model is used to process observations and estimate media characteristics. The model explicitly accounts for the optical activity of the TbFeCo layer, and is parameterized in terms of the index of refraction and thickness of the overcoat, and the real and imaginary parts of the elements of the dielectric tensor of the active layer.A series of TbFeCo films with varying composition, rf-sputter deposited on quartz substrates with Al2O3 dielectric protective overcoats, is characterized. Both Tb-rich and Fe-rich samples were deposited, with room temperature coercivities ranging from 1.6kOe to about 4kOe, and film-side Kerr rotations between 21 minutes and 28 minutes. Reflectivity data versus angle of incidence, and estimated dielectric tensor elements for the TbFeCo layers are presented. A standard figure of merit, based on the off-diagonal tensor elements, is used to compare competing media in terms of their optimal performance in a multilayered structure.

Sign in / Sign up

Export Citation Format

Share Document