Lewis‐Acid Stabilized Organoimide Complexes of Divalent Samarium, Europium, and Ytterbium

Abstract

Discrete organoimide complexes of the divalent rare-earth metals samarium, europium, and ytterbium are reported. Tandem salt metathesis-protonolysis reactions using Ln bis(tetramethylaluminate) precursors [Ln(AlMe ) ] and monopotassium salts of 2,6-diisopropylaniline (H NDipp) and triphenylsilylamine prove viable and efficient protocols. Depending on the ionic radius of the Ln metal centers and the steric demand of the imido carbon backbone, mono- and dilanthanide arrangements of general composition [(thf) Ln(NR)(AlMe )] (Ln=Sm, Eu, Yb; R=Dipp, SiPh ) are found in the solid state. Complex formation and stabilization is achieved by coordination of the Lewis acid AlMe , which also prevents formation of higher aggregated species. The feasibility of redox chemistry is shown with the plumbocene derivative Cp* Pb, providing access to the corresponding monomeric Ln half-sandwich complexes [Cp*Ln(NR)(AlMe )(thf) ] (Ln=Sm, Yb).

Divalent Lanthanide Tetraisobutylaluminates: Reactivity and Living Isoprene Polymerization

“…Plumbocene Pb(C 5 Me 5 ) 2 was initially probed as a redox equivalent toward 1 Ln (Ln = Sm, Yb), as it was already successfully used for accessing [(C 5 Me 5 ) 2 Ln-(AlR 4 )] from [Ln(AlR 4 ) 2 ] n (Ln = Sm, Yb; R = Me, Et). [32][33][34][35] Accordingly, single-crystalline [(C 5 Me 5 ) 2 Sm(AliBu 4 )] (2 Sm ) was obtained from treatment of 1 Sm with 1 equiv Pb(C 5 Me 5 ) 2 in quantitative yield (Scheme 2). Note that samarocene 2 Sm was described previously by Evans et al to form in the reaction of [(C 5 Me 5 ) 2 Sm(THF) 2 ] with TIBA (34 % yield), including its solid-state structure (see above).…”

Rare‐Earth Metal Diimide Complexes via Alkylaluminate Templating, Including a Ceric Derivative

“…Mindiola et al reported that methane eliminationf rom as candium(III) methyl anilide complex cannot only be induced by aL ewis base but also by aL ewis acid such as AlMe 3 to yield isolable complex [(PNP)Sc{N(Ar)AlMe 3 }] (PNP = N[2P-(CHMe 2 ) 2 -4-methylphenyl] 2 ,Ar = C 6 H 3 iPr 2 -2,6). [8] Such LA-stabilized organoimide complexes were later on accessedb yo ur groupf or Ln III (C-type) larger than Sc III [9,10] as well as Ln II metal centers (D-type), [11] utilizingd istinct alkylaluminate precursors. Representative examples include AlMe 3 -stabilizedc omplexes [Tp tBu,Me Ln(m-NR)(m-Me)AlMe 2 ]( Ln = Y, R = C 6 H 3 Me 2 -2,6, tBu, adamantyl;L n = Ho, R = tBu, adamantyl) [6,9] and HAlMe 2 -stabilized[ Tp tBu,Me Ln{m-N(C 6 H 3 Me 2 -2,6)}(m-H)AlMe 2 ] (Ln = Lu, Y).…”

Divalent metallocenes of the lanthanides – a guideline to properties and reactivity

“…[(C 5 Me 5 ) 2 Eu(THF) 2 ] was also synthesised from the metal and the plumbocene derivative [(C 5 Me 5 ) 2 Pb]. 51 Scheme 2 Synthesis [(Cp Bn5 ) 2 Ln] (Ln = Sm, Eu, Yb) via salt metathesis. 36 Scheme 3 Syntheses of title compounds starting from metals Eu and Yb in liquid ammonia.…”