Reactions of Bis(dibenzobarrelenyl) Dichalcogenides with a Palladium(0) Complex: Unexpected Formations of Mononuclear Chalcogenide(dichalcogenolato)palladium(II) Complexes and Dichalcogenahexacyclo Compounds

摘要

Thermal reactions of bis(dibenzobarrelenyl) dichalcogenides [(DbbS)_2 and (DbbSe)_2] with [Pd(PPh_3)_4] in toluene afforded novel mononuclear chalcogenide(dichalcogenolato)Pd~(II) complexes [Pd(EDbb-12-EDbb)(EDbb)(PPh3)] (E = S, Se) together with dichalcogenahexacyclo compounds. The reaction in the presence of PPh_3 in toluene at 110 °C led to a cyclometalation to furnish the corresponding four-membered 1,2-chalcogenapalladacycles [Pd(EDbb)(PPh_3)_2] (E = S, Se) with di- chalcogenahexacyclo compounds. The structures of these Pd~(II) complexes and cyclization products were fully characterized on the basis of their NMR spectroscopic data and Xray analyses. In the crystalline state of [Pd(SDbb-12-SDbb) (SDbb)(PPh3)], two thiolato sulfur atoms occupy cis positions with respect to the PPh_3, and the sulfide sulfur atom from the chelating sulfido(thiolato) ligand is situated at the trans position.