Raman optical activity , absolute

This chapter is not an update of a previous chapter and will therefore try to review the reported chiroptical data on the carbon-carbon double bond, starting from 1968. It will refer only to the available literature on the C=C chromophore itself. It will analyze the available data of molecules which contain only one chromophore, the carbon-carbon double bond. It will not dwell on molecules which have the C=C bond as one of the chromophores which are responsible for its optical activity. It will cover the literature in the field of electronic excitations and will not provide information on vibrational CD (VCD) or Raman optical activity. The chiroptical properties provide information regarding the spectroscopy of the chromophore, as well as its absolute configuration. The latter is usually done with the help of sector rules around the chromophore of interest. In this review both aspects will be discussed. 

Abstract Now an incisive probe of biomolecular structure, Raman optical activity (ROA) measures a small difference in Raman scattering from chiral molecules in right- and left-circularly polarized light. As ROA spectra measure vibrational optical activity, they contain highly informative band structures sensitive to the secondary and tertiary structures of proteins, nucleic acids, viruses and carbohydrates as well as the absolute configurations of small molecules. In this review we present a survey of recent studies on biomolecular structure and dynamics using ROA and also a discussion of future applications of this powerful new technique in biomedical research. 

Barron, L.D. Absolute eonfiguration of bromochlorofluo-romethane from experimental and ab initio theoretical vibrational Raman optical activity. Angew. Chem., Int. Ed. Engl. 1997, 36. 885-887. 

Vibrational Raman optical activity of biomolecules, including carbohydrates, has been reviewed (23 refs). l A general procedure for assigning both relative and absolute configuration to multiple stereocentres in acyclic aminopolyols based on application of the exiton chirality method is presented. The method has been applied to the side chain aminopolyol of a natural bacterial-derived terpenoid derivative. ... 

From the Raman optical activity of trans-2,3-dimethylthiirane the absolute configuration has been determined. Its experimental spectrum is very similar to that calculated ab initio, basis set 6-3IG ) for the 2R,3R-isomer [5] with best agreement in the skeletal vibration region. 

Debie E, De Gussem E, Dukor RK, Herrebout W, Nafie LA, Bultinck R A confidence level algorithm for the determination of absolute configuration using vibrational circular dichroism or Raman optical activity. ChemPhysChem 2011 12(8) 1542-1549. 

It is also interesting to note that circular differential Raman scattering, circular intensity differential (CID), has been reported for a series of optically active sulfoxides and a correlation found between the absolute configuration at sulfur and the differential scattering (240). Thus, all (/ )-alkyl p-tolyl sulfoxides investigated show a common (positive) CID feature in the 300 to 400 cm" region. 

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