with wavelength is measured, and a plot of either versus wavelength is often
related to the sense of chirality or the substance under consideration. In
general, the absolute value of the rotation increases as the wavelength
decreases. The plot of circular dichroism (CD) is the differential absorption
of left and right circularly polarized radiation by a nonracemic sample, taking
place only in spectral regions in which absorption bands are found in the
isotropic or visible electronic spectrum.116 The primary application of both
ORD and CD is for the assignment of configuration or conformation.117
Configurational and conformational analysis have been carried out using
infrared and vibrational circular dichroism (VCD) spectroscopies.118
In one example of the use of these techniques, one of the more effective
methods for derivatizing 1,2-diols is the method employing dimolybdenum
tetraacetate [Mo2(AcO)4] developed by Snatzke and Frelek.119 Exposure of the
resulting complex to air leads, in most cases, to a significant induced CD
spectrum (known as ICD). The method can be used for a variety of 1,2-diols
with wavelength is measured, and a plot of either versus wavelength is oftenrelated to the sense of chirality or the substance under consideration. Ingeneral, the absolute value of the rotation increases as the wavelengthdecreases. The plot of circular dichroism (CD) is the differential absorptionof left and right circularly polarized radiation by a nonracemic sample, takingplace only in spectral regions in which absorption bands are found in theisotropic or visible electronic spectrum.116 The primary application of bothORD and CD is for the assignment of configuration or conformation.117Configurational and conformational analysis have been carried out usinginfrared and vibrational circular dichroism (VCD) spectroscopies.118In one example of the use of these techniques, one of the more effectivemethods for derivatizing 1,2-diols is the method employing dimolybdenumtetraacetate [Mo2(AcO)4] developed by Snatzke and Frelek.119 Exposure of theresulting complex to air leads, in most cases, to a significant induced CDspectrum (known as ICD). The method can be used for a variety of 1,2-diols
การแปล กรุณารอสักครู่..