Samarium(III) Pentalene Sandwich Compounds [Sm(η8-C8H4{SiiPr3-1,4}2)(Cp*)] and [Sm(η8-C8H4{SiiPr3-1,4}2)(η5-C8H5{SiiPr3-1,4}2)] and a Mixed-Valence Hexasamarium Cluster Derived from Sm(II)-Based Solvent Activation

Abstract

The reaction of the pentalene salt C8H4{(SiPr3)-Pr-i-1,4}(2)[K](2) with [SmCp*(mu-I)(THF)(2)](2) yields not the expected Sm(II) pentalene-bridged dimer but the Sm(III) sandwich complexes [Sm(eta(8)-C8H4{(SiPr3)-Pr-i-1,4}(2))(eta(5)-Cp*)] (1) and [Sm(eta(8)-C8H4{(SiPr3)-Pr-i-1,4}(2))(eta(5)-C8H5{(SiPr3)-Pr-i-1,4}(2))] (2) and the mixed-valence cluster [Cp*Sm-6(6)(OMe)(8)O][K(THF)(6)] (3) via solvent activation of THF. The samarium(III) sandwich compound 2 incorporates an eta(8)-pentalene ligand and an eta(5)-hydropentalenyl ligand. X-ray crystallography shows the Sm(II)/Sm(III) mixed-valence cluster compound 3 to contain a centrosymmetric hexanuclear array of Cp*Sm units, bridged by face-centered mu(3)-methoxy groups, with a central oxo unit.