Closing the Gap: Preparation and Characterization of the First Half-Open and Open Manganocene Complexes

Structural characterization of potassium salts of the decamethylmanganocene anion Cp*2Mn. Dalton Trans 2019;48:17078-17082. [PMID: 31701989 DOI: 10.1039/c9dt03551f]

For the first time the crystal structure of a permethylated metallocene anion has been obtained. The 17 valence electron complex decamethylmanganocene Cp*₂Mn is reduced by molten potassium in THF to its extremely air-sensitive anion [Cp*₂Mn]^-. The potassium salt [K(THF)₂]⁺[Cp*₂Mn]^- crystallizes upon cooling from hot THF and forms infinite polymeric chains exhibiting strong KC contacts. In the presence of 18-crown-6 the polymeric structure is broken up. Crystals of [K(18-crown-6)(THF)₂]⁺[Cp*₂Mn]^- were obtained upon slow cooling from THF to -80 °C displaying well separated cations and anions.

Synthesis and molecular structure of pentadienyl complexes of the rare-earth metals

In combination with small and difficult to reduce rare-earth metals pdl′ undergoes CH-bond activations instead of sterically induced reductions to form dimeric complexes with a unique bridging six-membered metallacycle as the central structural motif.

Ligand conformations and spin states in open metallocenes of the first row transition metals having U-shaped 2,4-dimethylpentadienyl ligands

The lowest energy (2,4-Me₂C₅H₅)₂M structures (M = Ti, V, Cr, Mn, Fe) have the metal sandwiched between two U-shaped pentahapto pentadienyl ligands. However, those for the later transition metals Co and Ni contain one and two trihapto ligands, respectively.