A Novel Synthetic Pathway to Lanthanide Triple-Decker Complexes: Selective Expansion of a Sandwich Complex by an
Cedric Uhlmann1, Luca Münzfeld1, Adrian Hauser1
1Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstraße 12, Karlsruhe, Germany.
Abstract:
Commonly, multi-decker sandwich complexes can either be formed in a one-step reaction or in a stepwise fashion by stacking deck by deck. Herein, we showcase a new reaction pathway, in which for the first time a lanthanide half-sandwich unit inserts into an existing sandwich complex. As a result of the insertion of a cyclocene half-sandwich fragment {LnII(η8-CotTIPS)} (CotTIPS = 1,4-(iPr3Si)2C8H6 2-) into a classical divalent sandwich complex [LnII(η9-Cnt)2] (Ln = Sm, Eu, Yb; Cnt = C9H ), the unprecedented triple-decker sandwich complexes of the type [(η9-Cnt)LnII(μ-η8:η8-CotTIPS)LnII(η9-Cnt)] were obtained. A plausible reaction pathway was determined by quantum chemical calculations. Additionally, we synthesize the same lanthanide sandwich complexes in a traditional, stepwise fashion. For this, we initially present the novel inverse sandwich compounds [LnIII(thf)2(μ-η8:η8-CotTIPS)LnIII(thf)2] (Ln = Sm, Eu, thf = tetrahydrofuran) and [YbII(BH4)(thf)2(μ-η8:η8-CotTIPS)YbII(BH4)(thf)2] consisting of a cyclooctatetraene middle deck sandwiched between two divalent lanthanides as precursors. Subsequent salt metathesis reactions with [K(Cnt)] (Cnt = C9H ) gave rise to the title compounds [(η9-Cnt)LnII(μ-η8:η8-CotTIPS)LnII(η9-Cnt)]. The unique feature of these compounds is the combination of the two largest aromatic all-carbon rings known in coordination chemistry-the 8- and 9-membered rings-into lanthanide triple-decker sandwich compounds.
More Related Videos
Related Concept Videos
Cycloaddition Reactions: Overview
Ziegler–Natta Chain-Growth Polymerization: Overview
Cycloaddition Reactions: MO Requirements for Thermal Activation
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry


