Conformations and rotation of -propyl groups attached to the same saturated carbon centre. A dynamic N.M.R. and molecular mechanics study of 1,1,1-tris--propylethane, di- -propyl--butylmethane and 1,1-di--propyl--butylethane

The title compounds have temperature-dependent n.m.r. spectra from which rotational barriers for iso -propyl and tert -butyl groups can be determined. Molecular mechanics calculations are used to indicate the conformations involved in these rotations and other stable conformations, and the possible pathways for their interconversions.