Far ultraviolet spectroscopy; electronic trransitions from sigma molecular orbital in saturated molecules—challenge to sigma chemistry

In fifteen words or less, explain the significance of this contribution (Novel Aspect).: Hyperconjugation of saturated alkyl groups studied by electronic spectroscopy.

Abstract Text:

The purpose of the present study is to demonstrate the potential of far-ultraviolet spectroscopy for analyzing the hyperconjugation. Applications of far-UV spectroscopy (particularly FUV spectroscopy using the spectral region below 200 nm) have not been popular because the measurement atmosphere has been limited due to a strong absorption arising from oxygen. Recently, there has been significant progress in FUV instrumentation. We carried out systematic study of electronic transitions of n-alkanes and cycloalkane and their derivative. Electronic transitions from sigma electron of these saturated alkyl moiety were observe. We found that the transitions from these sigma electrons shifted when hydroxyl or ether groups were introduced. This means that the sigma electrons were hyperconjugated by the adjacent functional groups. Interestingly, we also report that when the hydroxyl group was hydrogen-bonded, the transitions of the sigma electrons of the bonded alkyl group were also affected.