Measuring the Optical Rotation Angle and Circular Dichroism of Anisotropic Optical Media Using a Heterodyne Polarimeter

2013 ◽  
Vol 31 (8) ◽  
pp. 1255-1262 ◽  
Author(s):  
Yu-Lung Lo ◽  
Chia-Chi Liao ◽  
Chang-Ye Li ◽  
Bo-Sung Shin ◽  
Sang-Mae Lee
Keyword(s):  
Circular Dichroism ◽  
Rotation Angle ◽  
Optical Rotation ◽  
Optical Media ◽  
Circular Dichroïsm

scholarly journals Absolute Configuration Sensing of Chiral Aryl- and Aryloxy-Propionic Acids by Biphenyl Chiroptical Probes

Chemosensors ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 154
Author(s):  
Stefania Vergura ◽  
Stefano Orlando ◽  
Patrizia Scafato ◽  
Sandra Belviso ◽  
Stefano Superchi
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Optical Rotation ◽  
Environmental Pollutants ◽  
Red Shift ◽  
Electronic Circular Dichroism ◽  
Configuration Assignment ◽  
Clear Sign ◽  
The Absolute ◽  
Circular Dichroïsm

The absolute configuration of chiral 2-aryl and 2-aryloxy propionic acids, which are among the most common chiral environmental pollutants, has been readily and reliably established by either electronic circular dichroism spectroscopy or optical rotation measurements employing suitably designed 4,4′-disubstituted biphenyl probes. In fact, the 4,4′-biphenyl substitution gives rise to a red shift of the diagnostic electronic circular dichroism signal of the biphenyl A band employed for the configuration assignment, removing its overlap with other interfering dichroic bands and allowing its clear sign identification. The largest A band red shift, and thus the most reliable results, are obtained by employing as a probe the 4,4′-dinitro substituted biphenylazepine 3c. The method was applied to the absolute configuration assignment of 2-arylpropionic acids ibuprofen (1a), naproxen (1b), ketoprofen (1c) and flurbiprofen (1d), as well as to the 2-aryloxypropionic acids 2-phenoxypropionic acid (2a) and 2-naphthoxypropionic acid (2b). This approach, allowing us to reveal the sample’s absolute configuration by simple optical rotation measurements, is potentially applicable to online analyses of both the enantiomeric composition and absolute configuration of these chiral pollutants.

scholarly journals A New Neolignan from Panicum turgidum

2016 ◽  
Vol 11 (7) ◽  
pp. 1934578X1601100
Author(s):  
Ahmed A. Zaki ◽  
Zulfiqar Ali ◽  
Yasser A. El-Amier ◽  
Ikhlas A. Khan
Keyword(s):  
Circular Dichroism ◽  
Optical Rotation ◽  
2D Nmr ◽  
Circular Dichroism Spectroscopy ◽  
Spectroscopic Methods ◽  
Relative Configuration ◽  
Esi Ms ◽  
Spectroscopy Optical ◽  
Circular Dichroïsm

A new neolignan, paniculignan (1), and a known lignan, tetracentronside B (2), were isolated from Panicum turgidum. The structure of 1 was elucidated by extensive spectroscopic methods including 1D and 2D NMR and HR-ESI-MS. The relative configuration of 1 was determined on the basis of circular dichroism spectroscopy, optical rotation, and NOESY correlations.

Origin of the optical activity of silver thiogallate

2000 ◽  
Vol 33 (1) ◽  
pp. 126-129 ◽  
Author(s):  
J. Etxebarria ◽  
C. L. Folcia ◽  
J. Ortega
Keyword(s):  
Circular Dichroism ◽  
Optical Activity ◽  
Room Temperature ◽  
Optical Rotation ◽  
Linear Dichroism ◽  
Optical Data ◽  
Point Dipole ◽  
Reliable Measurement ◽  
Photoelastic Modulator ◽  
Circular Dichroïsm

Using a high-accuracy universal polarimeter, the birefringence and optical activity of AgGaS2have been determined between 300 and 500 K. The optical rotation has been found to be 94° mm−1at room temperature for a wavelength of 632.8 nm. This value is unexpectedly small if compared with values close to 1000° mm−1at 485 nm reported previously. The present optical data are well explained using a point-dipole model for the calculation of the refractive indices and optical activity. The main contributors to the optical rotation are the S atoms. However, these atoms are not at positions especially suitable to promote extremely large gyrations. Consequently, the size of the optical rotation reported before in the blue part of the spectrum is presumably due to the existence of a circular dichroism band close to that region. Using an optical system based on a photoelastic modulator, a strong linear dichroism peak has been measured in the range 450–500 nm. This fact has prevented reliable measurement of the circular dichroism.

scholarly journals DETERMINATION OF THE POLARIZATION OPTICAL PROPERTIES OF THE AMYLOID-CONGO RED COMPLEX BY PHASE MODULATION MICROSPECTROPHOTOMETRY

1974 ◽  
Vol 22 (12) ◽  
pp. 1105-1112 ◽  
Author(s):  
DOUGLASS L. TAYLOR ◽  
ROBERT D. ALLEN ◽  
EARL P. BENDITT
Keyword(s):  
Circular Dichroism ◽  
Congo Red ◽  
Phase Modulation ◽  
Optical Rotation ◽  
Polarized Light ◽  
Visible Spectrum ◽  
Linear Dichroism ◽  
Cotton Effect ◽  
Optical Rotatory Dispersion ◽  
Circular Dichroïsm

The polarization properties responsible for the classical "green birefringence" of the amyloid-Congo red complex have been determined by a new optical method, phase modulation microspectrophotometry. This method now makes possible the measurement of one optical property at a time (birefringence, optical rotation, linear dichroism and circular dichroism throughout the visible spectrum) in complex specimens in which visible contrast in polarized light is the result of a mixture of polarization effects. The green birefringence is explained by a combination of optical effects, the strongest of which are dispersion of birefringence and linear dichroism superimposed on the smaller effects of circular dichroism and optical rotatory dispersion. The interaction of the planar dye molecules with the amyloid protein induces an extrinsic Cotton effect.

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