Potential for rotation about C( sp2)-O and C( sp2)-S bonds: electron diffraction results for CH 2CH-OCH 3 and CH 2

Abstract

Electron diffraction of gaseous methyl vinyl ether and methyl vinyl sulphide show that both compounds exist as a mixture of two conformers, one of these is the syn form with a planar heavy atom skeleton. For methyl vinyl ether the second conformer may also have a planar skeleton ( anti form), but a gauche form with a torsional angle close to 180° cannot be ruled out. For the sulphide a gauche form is found. Structural parameters are given in Table 2. Ab initio calculations gave energy minima for syn and anti forms for CH 2CH-OH and for syn and gauche forms for CH 2CH-SH.