New Type of Reaction of Lanthanide Hydrido Complexes with C60: Oxidative Dehydrogenation vs Addition. The Reversible σ-C60−C60 Bond Formation in Complex [{(Me3Si)2NC(NCy)2}2Lu(Et2O)+](C60−•)

Realization of Organocerium-Based Fullerene Molecular Materials Showing Mott Insulator-Type Behavior

Electron-rich organocerium complexes (C5Me4H)3Ce and [(C5Me5)2Ce(ortho-oxa)], with redox potentials E1/2 = -0.82 V and E1/2 = -0.86 V versus Fc/Fc+, respectively, were reacted with fullerene (C60) in different stoichiometries to obtain molecular materials. Structurally characterized cocrystals: [(C5Me4H)3Ce]2·C60 (1) and [(C5Me5)2Ce(ortho-oxa)]3·C60 (2) of C60 with cerium-based, molecular rare earth precursors are reported for the first time. The extent of charge transfer in 1 and 2 was evaluated using a series of physical measurements: FT-IR, Raman, solid-state UV-vis-NIR spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy, and magnetic susceptibility measurements. The physical measurements indicate that 1 and 2 comprise the cerium(III) oxidation state, with formally neutral C60 as a cocrystal in both cases. Pressure-dependent periodic density functional theory calculations were performed to study the electronic structure of 1. Inclusion of a Hubbard-U parameter removes Ce f states from the Fermi level, opens up a band gap, and stabilizes FM/AFM magnetic solutions that are isoenergetic because of the large distances between the Ce(III) cations. The electronic structure of this strongly correlated Mott insulator-type system is reminiscent of the well-studied Ce2O3.

Effective magnetic coupling with strong spin frustration in (Ph3MeP+)(C60˙−) and reversible C60˙− dimerization in (Ph3MeP+)(C60˙−)·C6H5CN. Effect of solvent on structure and properties

Antiferromagnetic coupling of spins with spin frustration and fullerene dimerization are observed for (Ph₃MeP⁺)(C₆₀˙⁻) (left) and (Ph₃MeP⁺)(C₆₀˙⁻)·C₆H₅CN (right).

Design, crystal structures and magnetic properties of anionic salts containing fullerene C60 and indium(iii) bromide phthalocyanine radical anions

Salts containing fullerene C₆₀ and indium(iii) bromide phthalocyanine (Pc) radical anions, (TBA⁺)₃(C₆₀˙⁻){In^III(Br)(Pc)˙⁻}(Br⁻)·C₆H₄Cl₂ (1) and (TEA⁺)₂(C₆₀˙⁻){In^III(Br)(Pc)˙⁻}·C₆H₄Cl₂·C₆H₁₄ (2), have been obtained and their structures, optical and magnetic properties are discussed.

A double addition of Ln-H to a carbon-carbon triple bond and competitive oxidation of ytterbium(II) and hydrido centers

Addition of two Ln-H bonds of an Yb(II) hydrido complex supported by bulky amidinate ligand to a C≡C bond lead to the formation of 1,2-dianionic bibenzyl fragment. Both Yb(II) and hydrido centers are oxidized under the reaction conditions. The resulting Yb(II)-η(6) -arene interaction is surprisingly robust: the arene cannot be replaced from the metal coordination sphere when treated with Lewis bases.