Synthesis of Organometallic Mixed Sulfur-Selenium π-Acceptor Molecules.

The reactive dianion, 4,5-diselenolato-1,3-dithiole-2-thione (dsit) was prepared by the reaction of 1,3-dithiole-2-thione with in-situ generated lithium diisopropylamide and finely powdered elemental selenium. Addition of methanolic-ammoniacal solutions of the appropriate metal (nickel and palladium) dichlorides to the above reaction mixture followed by methanolic solutions of tetraalkylammonium [tetrabutylammonium (TBA) and tetraethylammonium (TEA)] bromide, results in the precipitation of dark colored solids from the solutions. Isolation and purification of these solids revealed that the solids had the general composition (TAA)2[M(dsit)2] where TAA were tetrabutylammonium or tetraethylammonium anions and M were Ni(II) and Pd(II). Electrochemical or chemical oxidation of the nickel(II) organometallic complexes resulted in the formation of the π-acceptor (TBA) [Ni(dsit2)] while a similar reaction with the palladium(II) complexes failed to produce the equivalent (TAA) [Pd(dsit)2].