POTENTIAL FOR ROTATION ABOUT C(SP2)-S BONDS - ELECTRON-DIFFRACTION RESULTS FOR O=C(SCH3)2 AND ABINITIO CALCULATIONS ON O=CH-SH AND S=CH-SH

Gaseous S,S′-dimethyldithiocarbonate, OC(SCH3)2, has been investigated using electron diffraction and the experimental data are consistent with a syn-syn conformation. The most important structural parameters are: ra(CO) = 1.206(4) Å, ra(CcarbS) = 1.777(3) Å, ra(CMeS) = 1.802(4) Å, ∠ OCS = 124.9(2)° and ∠ CSC = 99.3(4)°. The standard deviations are given in parentheses. Ab initio calculations have been carried out on monothioformic acid, OCHSH, and dithioformic acid, SCHSH. The calculations gave energy minima for syn and anti forms. © 1979.