Synthesis, Reactivity, and Stability of Di- and Trivalent Samarium Amides

Abstract

SmCl 3 (THF) 3 (THF ) tetrahydrofuran) reacts with anionic dialkylamides R 2 N -[R ) Cy (cyclohexyl), i-Pr (isopropyl), Ph (phenyl)] to give different products, depending on the nature of the R substituents. Reaction with Cy 2 NLi in a 1:2 molar ratio formed [(Cy 2 N) 2 Sm(µ-Cl)(THF)] 2 (1) in 80% yield, whereas reaction with (i-Pr) 2 NLi under similar conditions gave [(i-Pr 2 N) 2 SmCl 3 (Li(TMEDA)) 2 ] (2). Partial loss of THF from complex 1 reorganized the molecule into the tetranuclear (Cy 2 N) 6 Sm 4 Cl 6 (THF) 2 (3). Attempts to reduce complex 1 with a number of reagents gave [(Cy 2 N) 3 SmTHF]‚toluene (5), while [(Cy 2 N) 4 SmLi(THF)] (4) was isolated upon alkylation reactions carried out with either NpLi or NfLi [Np ) CH 2 C(CH 3 ) 3 ; Nf ) CH 2 C(CH 3 ) 2 Ph]. Direct synthesis of Sm(II) amides from SmI 2 (THF) 2 starting material was successful only in the case of diphenylamide anion (Ph 2 N -). Depending on the stoichiometry, -ate (Ph 2 N) 4 Sm[Na(TMEDA)] 2 (6) or neutral [(Ph 2 N) 2 Sm(THF) 4 ]‚THF (7) was obtained. The crystal structures of 1-7 were demonstrated by X-ray diffraction analysis. Crystal data are as follows. 1: C 56 H 105 N 4 O 2 Sm 2 Cl 2 , triclinic,

Syntheses, crystal structures and catalytic properties of a series of lanthanide(III) bis(trimethylsilyl)amide chloride complexes: [{((Me3Si)2N)2Nd(μ′-Cl)Li(THF)3}(μ-Cl)]2, [{((Me3Si)2N)2Ln(μ′-Cl)Li(THF)2}(μ3-Cl)]2 (Ln=Eu, Ho), and [{(Me3Si)2NLn(μ′-Cl)2Li(THF)2}(μ-Cl)]2 (Ln=Nd, Sm, Eu, Ho, Yb)

“…The mean Ln-l 0 -Cl(1) and Ln-l 0 -Cl(2) bond distances are slightly shorter than those of Ln-l-Cl (3) and Lnl-Cl(3 0 ) bonds. The average Sm-l-Cl bond distance (2.754 Å ) is shorter than those observed in [(Cy 2 N) 2 Sm(l-Cl)(THF)] 2 (2.800 Å ) and [(iPr 2 N) 2 SmCl 3 {Li(TMEDA)} 2 ] (2.802 Å ) [33]. The average Eu-l-Cl bond distance (2.741 Å ) is longer than those observed in [(Me 3 Si) 2 N] 3 Eu(l-Cl)Li(THF) 3 (2.650(2) Å ) [12].…”

“…The tetrahedral coordination sphere of each Li atom is completed by one l 0 -Cl, one l 3 -Cl and two O atoms from THF molecules. The mean Li-l 0 -Cl bond distance (2.361(7) Å (2) and 2.33(1) Å (3)) is comparable to that in 1, but longer than that in [(iPr 2 N) 2 SmCl 3 {Li(TME-DA)} 2 ] (2.285 Å ) [33]. The mean Li-l 3 -Cl bond length (2.509(6) Å (2) and 2.54(2) Å (3)) is longer than that in [(iPr 2 N) 2 SmCl 3 {Li(TMEDA)} 2 ] (2.335 Å ) [33].…”

“…The mean Li-l 0 -Cl bond distance (2.361(7) Å (2) and 2.33(1) Å (3)) is comparable to that in 1, but longer than that in [(iPr 2 N) 2 SmCl 3 {Li(TME-DA)} 2 ] (2.285 Å ) [33]. The mean Li-l 3 -Cl bond length (2.509(6) Å (2) and 2.54(2) Å (3)) is longer than that in [(iPr 2 N) 2 SmCl 3 {Li(TMEDA)} 2 ] (2.335 Å ) [33]. The mean Li-O bond length (1.909 Å (2) and 1.91 Å (3)) is shorter than that in 1.…”

Structural Elucidation of tmeda‐Solvated Alkali Metal Diphenylamide Complexes

“…[47,48] Contacted ate complexes are also prevalent, predominantly with the heavier alkali metals (sodium and potassium) due to their need for further stabilisation by metal-arene π-interactions. [36,[49][50][51][52][53][54] Turning to homometallic species, lithium diphenylamide has been shown to form co-complexes with: (i) lithium chloride; [55] (ii) n-butyllithium and mono-ortho-metallated LiNPh 2 ; [56] and (iii) dilithium diphenylhydrazide. [57] But perhaps most pertinent to this study, several alkali metal diphenylamides stabilised by donor ligands (e.g., various ethers [58][59][60][61][62] and pyridine [58] ) have been reported.…”

Zinc(II), Samarium(III) and Tin(II) Complexes Featuring a Tridentate Nitrogen Donor for the Ring-Opening Copolymerization of (D,L)-Lactide and Glycolide

“…[17] Complex 3 also adopts a dimeric structure but the two [(Me 3 SiNCH 2 CH 2 ) 2 NMe]Sm(THF) units are bridged by two chlorine atoms ( Figure 2). As observed in [(Cy 2 N) 2 Sm(µ-Cl)(THF)] 2 , [19] the amido nitrogens are in a trigonal planar environment and the (SmϪCl) 2 core is perfectly planar. However, each samarium atom is hexacoordinate and has a strongly distorted octahedral geometry.…”