The conformational/configurational dependence of the frequencies of the deuteriumhyphen;isolated Cndash;H stretching modes of the gashyphen;phase alkanes C1, C2,nhyphen;C3,nhyphen;C4(tandg),nhyphen;C5(ttandgt), cyclohyphen;C6, isohyphen;C4, and neohyphen;C5are reported. Most of the isolated Cndash;H frequencies were obtained from Raman spectra of specifically and randomly protonated deuterohydrocarbons. An extraordinarily precise correlation is found between the observed isolated Cndash;H frequencies and the correspondingabinitiocalculated Cndash;H bond lengths. In the case of thenhyphen;alkanes, the observed Cndash;H frequencies tend to fall in clusters that are regularly spaced with an average separation of about 14.5plusmn;1 cmminus;1. The clustering occurs because the isolated Cndash;H stretching frequencies are determined by the structure of thenhyphen;alkane in the immediate vicinity of the Cndash;H bond. The relation between frequency and local structure can be expressed in a simple way and used to predict the effect of conformational change.
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