Hyperconjugation anomeric effect, relation

Charge transfers that may accompany the anomeric effect, though unmeasurable by the X-ray diffraction method, may result in changes in spectral properties of molecules. It is probably impossible to relate a given spectral property directly to the anomeric effect in its phenomenological sense. An alternative approach should then be applied, namely to relate the spectral observation to negative hyperconjugation (as the most probable cause of the anomeric effect). 

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