Conformational stability and vibrational analysis of a series of branched octanes III: trimethyl pentanes

Abstract

This communication presents the detailed results of systematic analyses by the method of molecular mechanics of the conformations of the entire series of trimethyl pentanes (TMP). Normal-mode calculations of the frequencies of the most stable conformations have been made with the use of the local-symmetry force field (LSFF). In the case of 2,2,3-TMP it was possible to evaluate the enthalpy of the conformational equilibrium by quantitative analyses of the effect of temperature on the observed spectra. Furthermore, certain effects of intermolecular interactions on the conformations of these relatively flexible molecules have been established.