The Chemical and Physical Properties of Polychalcogens: Dialkoxydisulfides, Thionosulfites and Polysulfides

The optimized synthesis of acyclic dialkoxy disulfides and aromatic polysulfides is described and their physical properties probed. In particular, the origin of the high barrier to rotation in the dialkoxy disulfides was determined to be due to a generalized anomeric effect. The origin of the high rotational barrier was also verified experimentally. Complimentary to this thermal process, the decomposition of dialkoxy disulfides was also investigated. Theoretical modeling on the relative ground state energies of dialkoxy disulfides is also described. It has been ascertained that the equilibrium position between the two isomers can be influenced by the ring size of the molecule; larger rings promote the dialkoxy disulfide isomer. These modeling studies were successfully corroborated experimentally. The kinetics of desulfurization of acyclic aromatic tri- and tetrasulfides is described. Tetrasulfides were found to transfer a sulfur atom to triphenylphosphine over ten times faster than their trisulfide analogues.