| Abstract: | The temperature dependence of the proton chemical-shift difference between the methyl and methylene groups in the unbranched paraffin hydrocarbon C44H90 was calculated by using Pople's approximation and the Monte Carlo method, and the calculated results could interpret the experimental behavior in carbon tetrachloride solution. From these results, it was estimated that the energy difference between the trans and gauche states is 1880–2300 J/mol, and the four-bond interaction energy is 5270–6275 J/mol. The estimated values agree with those obtained from comparison of the calculated and observed average-dimension and its temperature coefficient by Abe et al. Further, the calculated chemical-shift difference was associated with the unperturbed dimension and its temperature coefficient. |
