Reactivity of the Ln2+ Complexes [K(2.2.2-cryptand)][(C5H4SiMe3)3Ln]: Reduction of Naphthalene and Biphenyl

The reductive capacity of the recently discovered Ln2+ complexes [K(2.2.2-cryptand)][Cp′3Ln], 1-Ln (Cp′ = C5H4SiMe3; Ln = Y, La, Ce, Dy), has been probed by examining their reactions with aromatic hydrocarbons. [K(2.2.2-cryptand)][Cp′3Y], 1-Y, is capable of reducing naphthalene and forms a mixture of the naphthalenide dianion complex [K(2.2.2-cryptand)][Cp′2Y(η4-C10H8)], 2-Y, as well as the ligand redistribution product [K(2.2.2-cryptand)][Cp′4Y], 3-Y, and the cyclopentadienyl ligand salt [K(2.2.2-cryptand)][Cp′], 4. Naphthalene is reduced analogously by 1-La, 1-Ce, and 1-Dy. Each complex in the yttrium reaction was synthesized independently to confirm its identity in the mixture. Complex 2-Y was prepared from [Cp′2Y(THF)2][BPh4], 5 (synthesized from [Et3NH][BPh4] and Cp′3Y), and K/naphthalene. Complex 3-Y was obtained by adding KCp′ to Cp′3Y in the presence of 2.2.2-cryptand. [K(2.2.2-cryptand)][Cp′] was synthesized from 2.2.2-cryptand and KCp′. Each C10 unit in the reduced naphthalene products, 2-Y, 2-L...