Isomeric Dithienophosphepines: The Impact of Ring Fusion on Electronic and Structural Properties
We present the synthesis and extensive experimental (X-ray crystallography, UV-Vis spectroscopy, cyclic voltammetry) and theoretical (DFT calculations) characterization of two isomeric dithieno[b,f]phosphepines (DTPs). The relative orientation of the phosphepine and the thiophene moieties has a decisive impact on the electronic and structural properties of these compounds. Moreover, the thiophene units allow for a facile subsequent functionalization via direct Pd-catalyzed C-H coupling, which renders DTPs highly promising building blocks for organophosphorus functional materials.
We have used IR spectroscopy to study the reaction between L-cysteine and dimethyl sulfoxide in aqueous medium. We have found that reaction occurs with formation of an insoluble product, which we have identified. We show that oxidation of L-cysteine by dimethyl sulfoxide can occur at an appreciable rate under mild conditions, with formation of L-cystine, dimethyl sulfide, and water.