Europium bis(dimethylsilyl)amides including mixed-valent Eu₃[N(SiHMe₂)₂]₆[μ-N(SiHMe₂)₂]₂

Abstract

Trivalent Eu[N(SiHMe2)2]3(THF)2 can easily be synthesized by applying a routine salt metathesis protocol (EuCl3(THF)2 and 3 equiv. of Li[N(SiHMe2)2] in n-hexane) which crystallizes isotypically to its analogues of the rare-earth metal series (space group P21/c). Transsilylamination of Eu[N(SiMe3)2]2(THF)2 with a slight excess of HN(SiHMe2)2 in n-hexane-THF yields the divalent trinuclear compound Eu{[μ-N(SiHMe2)2]2Eu[N(SiHMe2)2](THF)}2, the solid-state structure of which differs significantly from the samarium and ytterbium analogues by showing three unique molecules in the asymmetric unit of which one is related to the two others by an inversion. Using crude Eu[N(SiMe3)2]3 in transsilylamination reactions with HN(SiHMe2)2 in n-hexane afforded n-hexane-insoluble trivalent ate complexes {MEu[N(SiHMe2)2]4}n (M = Na, K) depending on the synthesis conditions of Eu[N(SiMe3)2]3. Performing the transsilylamination of Eu[N(SiMe3)2]3 with a large excess of HN(SiHMe2)2 at elevated temperatures gave reproducibly the donor-free, mixed-valent, trinuclear compound Eu(II){[μ-N(SiHMe2)2]Eu(III)[N(SiHMe2)2]3}2 in good yield.

Homoleptic Trivalent Tris(alkyl) Rare Earth Compounds

“…The 29 Si INEPT NMR room temperature resonance at -13.1 ppm split into two signals at 190 K, with one at -9.3 (assigned to Ln↼H-Si) and the other at -18.5 ppm. Although the two types of SiHs give very different one-bond coupling constants, the 29 Si NMR chemical shifts are surprisingly similar and upfield.…”

“…The 29 Si INEPT NMR room temperature resonance at -13.1 ppm split into two signals at 190 K, with one at -9.3 (assigned to Ln↼H-Si) and the other at -18.5 ppm. Although the two types of SiHs give very different one-bond coupling constants, the 29 Si NMR chemical shifts are surprisingly similar and upfield. These values contrast the downfield 29 Si NMR signals that might be expected from structures in which the Si-H bond is partly broken from an arrested b-H elimination, either in the form of a partially-formed silene or a partly-formed silylium site.…”

Yttrium Siloxide Complexes Bearing Terminal Methyl Ligands: Molecular Models for Ln−CH3 Terminated Silica Surfaces

“…[25] The 6-coordinate yttrium centers are arranged in an almost linear way (Y2-Y1-Y3 175.18 (2)8 crown-6) [47] and mixed-valent amide complex[ Eu[{m-N(SiH-Me 2 ) 2 }Eu{N(SiHMe 2 ) 2 } 3 ] 2 ]( Eu-Eu-Eu 167.972 (7)8). [48] (3) ). [49] [Y(CH 3 )(GaMe 4 ){OSi(OtBu) 3 (2) ), [26] buta re in the range of those observed in half-sandwich and metallocene complexes.…”

Highly Fluorinated Tris(indazolyl)borate Silylamido Complexes of the Heavier Alkaline Earth Metals: Synthesis, Characterization, and Efficient Catalytic Intramolecular Hydroamination

“…Trinuclear homoleptic Mg compounds displaying two different ligand environments in a 1:2 ratio for the terminal and bridging positions are more common. [62][63][64][65] Trinuclear divalent lanthanide complexes of composition Ln{[m-N(SiHMe 2 ) 2 ] 2 Ln[N(SiHMe 2 ) 2 ](thf)} 2 (Ln = Sm, [66] Yb, [67] and Eu [68] ) have been also described. As in the case of complex 4, the coordinatively unsaturated and electron-deficient Ln(II) )] with an excess of 4 in pentane over a period of 2 days, followed by extraction with a 1:3 toluene/pentane mixture, provided 5 in 37 % yield (Scheme 5).…”