Knowledge Bank

Syn-Methyl sulfine, $CH3CH=S=0$, has been identified by its microwave spectrum as a low pressure thermolysis product of t-butyl vinyl sulfoxide. The ground state spectrum is very strongly affected by internal rotation of the methyl group. Assignments of a-dipole transitions of the A” symmetry species give rotational constants A = 14.2 GHz, B = 4678.53 MHz, and C = 3594.63 MHz. Tentative assignments of several $K_{-1} = 0$ transitions of the E” symmetry species imply a $V3$ methyl barrier to internal rotation of about 400 cal/mole. Stark effect measurements give an a” dipole component of 2.7 D and a b” dipole component of about 1.5 D.""