Optical rotation dispersion

Kronman, M. J., Blum, R. and Holmes, L. G. 1966. Inter- and intramolecular interactions of a-lactalbumin. VI. Optical rotation dispersion properties. Biochemistry 5, 1970-1978. 

However, as the optical rotation dispersion curves between 250 and 589 m/t of some poly-acrylic and poly-methacrylic esters seem to be anomalous1 relationship between optical activity and conformation in... 

Section II, 1. Theoretical aspects of asymmetric polymerization have been discussed by Fueno and Furdkawa [T. Fueno, J. Furukawa J. Polymer Sci., Part A, 2, 3681 (1964)]. 1-phenyl-l,3-butadiene has been polymerized using (R)-2-methyl-butyl-lithium or butyl-lithium complexed with menthyl-ethyl-ether, yielding optically active polymers with [a] f, referred to one monomeric unit, between +0.71 and —1.79. Optical rotation dispersion between 589 m u and 365 mft is normal and the Drude equation constant is comprised between 255 raft and 280 raft [A. D. Aliev, B. A. Krenisel, T. N. Fedoiova Vysokomol. Soed. 7, 1442 (1965)]. 

The optical rotatory dispersion of poly-(+)-l-methyl-benzyl-methacry ate has been measured between 320 and 230 raft. The optical activity for polymer and model has values of the same sign and of the same order of magnitude, but the isotactic polymer seems to have a larger [M] than the syndiotactic and the atactic polymers [K. J. Liu, J. S. Lignowski, R. Ullman ACS Polymer Preprints, 6, 904 (1965)]. Optically active N-methyl-N-methylbenzyl-acrylamide and N-(n-propyl)-N-methylbenzyl-acrylamide have been polymerized by Kaiser and Schulz and the optical rotation dispersion between 589 raft and 365 raft has been... 

Several physicochemical methods of investigation, such as measurement of optical rotation (including optical rotation dispersion and circular dichroism) rheological methods, and X-ray analysis of fibers and films, have played a very important role for determination of conformations of galactan molecules and characterization of their supramolecular structures.8,19 As mentioned in Section I, only physicochemical methods used for determination of primary structures of polysaccharides are considered in this chapter. 

Many media exhibit optical activity which depends on wavelength, i.e., optical rotation dispersion. Quartz is an example. 

The pitch P is the most important parameter of cholesteric liquid crystals. The physical properties of cholesteric liquid crystals are associated with P, such as selective reflection, optical rotation dispersion, circular dichroism, etc. The helical pitch is sensitive to the temperature and external field, for example, electric and magnetic field, chemical environment, pressure or radiation, etc. 

From another point of view MCD can be regarded as the absorptive counterpart of magnetic optical rotation dispersion (MORD) the well-known Faraday effect. This is the reason why in the past the spectra were given in the units of natural optical rotation per magnetic field... 

Faraday found experimentally that all substances show this effect in presence of a magnetic field (Schatz and Me Caffery, 1969), leading to Magnetic optical rotation dispersion (MORD) and Magnetic circular dichroism (MCD) (Caldwell and Eyring, 1976 Dawber, 1964 Foss and Mccarvil, 1965 Schatz et al., 1978 Thome, 1977). Experimentally however, ORD and MORD were never measured extensively contrary to CD and MCD. 

In the examination of optically active compounds, optical rotational dispersion (ORD) and circular dichroism (CD) have been applied with success [111], Analysis took place in a conventional way extracting samples out of the reaction solution with off-line analysis in CD equipment. 

Blaha K, Kavkova K, Koblicova Z, Trojanek J (1968) On alkaloids XX. Absolute configuration of alkaloids of eburnane series. Optical rotation dispersion. Coll Czech Chem Commun 33 3833-3840... 

R81 S.-D. Zhao, L. Shen, D.-Q. Luo and H.-J. Zhu, Progression of Absolute Configuration Determination in Natural Product Chemistry Using Optical Rotation (Dispersion), Matrix Determinant, and Electronic Circular Dichroism Methods , Curr. Org. Chem., 2011, 15, 1843. 

The stereochemistry and absolute configuration of a variety of dimers, prepared by electrolytic or chemical oxidation of (S)-( — )- -methylcorypalline have been elucidated through careful analysis of their ORD (optical rotation, dispersion) and CD (circular dichroism) curves... 

It is well known that the CD is always accompanied by an optical rotation dispersion (Cotton effect). Such a Cotton effect has also been observed [108]. It is clear that a helically arranged system of emitting molecules should exhibit also a fluorescence circular dichroism. Such an effect has been reported very recently [110]. 

The analogous reaction of 83 with phloroglucinol (1,3,5-trihydroxybenzene) led to the corresponding isomer of type 87 in 10 % yield. The racemic mixture of this compound was resolved by chiral HPLC on Chiralpak ADH stationary phase using propan-2-ol/hexane (2 98) as mobile phase. The absolute configuration of the two separated enantiomers was determined by the comparison of experimentally measured optical rotation dispersion and electronic circular dichroism with DFT calculations of these chiroptical properties [39]. 

Optical measurements (/) such as Raman Scattering, Fluorescence techniques. Vibrational Circular Dichroism, (VCD), Optical Rotational Dispersion (ORD), Raman Optical Activity (ROA) and infrared absorption spectroscopy can overcome many of the obstacles mentioned above due to the fact that optical techniques are non-invasive and can monitor proteins in their native environment and with accurate time resolution. One disadvantage is the low sensitivity. However, the use of Surface Enhanced Raman Scattering (SERS), techniques (2-4) means that proteins can be observed down to the single molecule level. Thus, optical teclmiques hold great promise for the future investigation of protein dynamics processes provided that proteins can be maintained in a suitable and controllable sample cell. 

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