Synthesis and structure of dipalladium complexes containing cyclooctatetraene and bicyclooctatrienyl ligands

The reaction of a substitutionally labile dipalladium(I) complex [Pd2(CH3CN)6][BF4]2 (1) with 1,3,5,7-cyclooctatetraene (COT) in acetonitrile afforded [Pd2(μ-η3:η3-C8H8)(CH3CN)4][BF4]2 (2). The reaction of 2 with COT in acetonitrile yielded [Pd2(μ-η3:η3-C16H16)(CH3CN)4][BF4]2 (4), where COT is dimerized via C–C bond formation. Complexes 2 and 4 were structurally characterized by X-ray diffraction analyses. In dichloromethane, COT isomerized to styrene at room temperature in the presence of catalytic amount of 1, 2, or 4.