Photo- and electrochemical properties of di(cymantrenylalkyl) disulfides

• Study of photochemical behavior of di(cymantrenylalkyl)disulfide. • Preparation of stable bicyclic dicarbonyl chelates. • Preparation in situ of unstable fulvenes. • Study electrochemical properties of symmetrical disulfides. Photolysis of di(cymantrenylalkyl)disulfides was studied by IR, 1 H NMR and UV-vis spectroscopy. Irradiation of cymantrenes with a disulfide bridge results in the formation of two type dicarbonyl chelates with Mn-S bond. The first type is formed due to removal of one CO ligand from one cymantrenyl moiety to give a 5-membered chelate cycle; the other is formed due to removal of two CO ligands from two cymantrenyl moieties to form a bicyclic chelate. The latter was isolated and characterized by X-ray analysis. For the first time, unstable fulvenes were prepared in situ by irradiation of cymantrenyl derivatives or their dicarbonyl complexes. Electrochemical properties of disulfides were studied before and after photolysis in acetonitrile. The manganese oxidation potential value increased on going from tricarbonyls to dicarbonyls.