Chemistry of Weakly Solvated Lanthanide-Metal Cations. Synthesis, Characterization, and Catalytic Chemistry of x

Article abstract of DOI:10.1021/ja00274a039

The title compound, x, 1, was synthesized by the NOBF4 oxidation of metallic Eu in CH3CN.The interaction of the BF4^- ions with the Eu(III) center was established by molecular weight, conductivity, and 11B and 19F NMR spectral measurements. 1 was found to exist as a dimer in CH3CN.In addition, it behaved as a 1:2 electrolyte, indicating the coordination of two of the BF4^- ions per Eu(III) ion.However, the conductivity increased when chelating amines were added due to the partial displacement of the coordinated BF4^- ions.The 11B and 19F NMR spectra of 1 in CH3CN indicated the presence of two different types of BF4^- anions, one of which was isotropically shifted due to interaction with the paramagnetic Eu(III) center.The coordinated BF4^- anions could be displaced quantitatively by the addition of 2 equiv of NO3^- ions per Eu(III) ion.A degenerate metathesis of the fluorine between the BF3 and the coordinated BF4^- ions was observed when BF3 was added to a CH3CN solution of 1. 1 formed a charge-transfer complex with tetra-p-anisylethylene in CH3NO2 but not in CH3CN.In addition, 1 initiated the oligomerization and the polymerization of styrene, α-methylstyrene, and 1,3-cyclohexadiene in CH3NO2.The molecular weights of the polymers obtained increased markedly on lowering the reaction temperature.At room temperature, indan derivatives were obtained from α-methyl- and α-phenylstyrene.The rate of polymerization of styrene was markedly attenuated when CH3CN was used instead of CH3NO2. 1 also initiated the isomerization of quadricyclane and the ring-opening polymerization of 2(10)-pinene and cyclopropylbenzene in CH3NO2.