Electronic structures and dipole moments of 4- and 5-phenyl-1, 2-dithiol-3-thiones

The simple LCAO MO method is used to calculate π-electron configurations of 1,2-dithiol-3-thione and its 4- and 5-phenyl derivatives. In these compounds the heterocyclic ring has an aromatic character, but the S-S bond is almost excluded from conjugation. The phenyl group in 4-phenyl-1,2-dithiol-3-thione is an electron acceptor, whereas in the 5 isomer it is an electron donor. The exocyclic sulfur atom has considerable negative charge, while the two endocyclic ones are positively charged. The dipole moments of 4- and 5-phenyl-1,2-dithiol-3-thione are determined, and the values found are compared with the calculated ones.