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Optical rotation, also known as ... fructose, and glucose, ... where ^ and ^ are unit vectors, and i is the imaginary unit, in this case ...
Specific rotation is an intensive property, distinguishing it from the more general phenomenon of optical rotation. As such, the observed rotation ( α ) of a sample of a compound can be used to quantify the enantiomeric excess of that compound, provided that the specific rotation ( [α] ) for the enantiopure compound is known.
The specific rotation [] is a physical property and defined as the optical rotation α at a path length l of 1 dm, a concentration c of 10 g/L, a temperature T (usually 20 °C) and a light wavelength λ (usually sodium D line at 589.3 nm): [4]
The observed rotation of the sample is the weighted sum of the optical rotation of each anomer weighted by the amount of that anomer present. Therefore, one can use a polarimeter to measure the rotation of a sample and then calculate the ratio of the two anomers present from the enantiomeric excess, as long as one knows the rotation of each pure anomer.
Short wavelengths are rotated more than longer wavelengths, per unit of distance. Because the wavelength of light determines its color, the variation of color with distance through the tube is observed. [citation needed] This dependence of specific rotation on wavelength is called optical rotatory dispersion. In all materials the rotation ...
Glucose circulates in the blood of animals as blood sugar. [5] [7] The naturally occurring form is d-glucose, while its stereoisomer l-glucose is produced synthetically in comparatively small amounts and is less biologically active. [7] Glucose is a monosaccharide containing six carbon atoms and an aldehyde group, and is therefore an aldohexose ...
Stereoisomerism about double bonds arises because rotation about the double bond is restricted, keeping the substituents fixed relative to each other. [5] If the two substituents on at least one end of a double bond are the same, then there is no stereoisomer and the double bond is not a stereocenter, e.g. propene, CH 3 CH=CH 2 where the two ...
The "α" and "β" forms, which are not enantiomers, will usually crystallize separately as distinct species. For example, D-glucose forms an α crystal that has specific rotation of +112° and melting point of 146 °C, as well as a β crystal that has specific rotation of +19° and melting point of 150 °C. [4]