Two equivalent methyl internal rotations in 2,5-dimethylthiophene investigated by microwave spectroscopy

The microwave spectrum of 2,5-dimethylthiophene, a sulfur-containing five-membered ring with two conjugated double bonds, was recorded in the frequency range from2 to 40 GHz using molecular beam Fourier transform technique. Highly accurate molecular parameters were determined. A labeling scheme for the group G(36) written as the semi-direct product (C-3(I) x C-3(I)) C-2v was introduced.