Alkoxysilylamide des Neodyms, Samariums und Ytterbiums: Viergliedrige anorganische Ringsysteme in der Lanthanidchemie

Recknagel, Anja; Steiner, Alexander; Brooker, Sally; Stalke, D.; Edelmann, Frank T.

doi:10.1016/0022-328x(91)80131-3

Cited by 23 publications

(16 citation statements)

References 16 publications

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“…[20] In a similar manner, the bulky carbazolate (cbz) ligands are cisoid in six coordinate [Ln(cbz) 2 (thf) 4 ] (Ln ϭ Yb and Sm). [21,22] The YbϪN distances are nearly identical with those of six coordinate [YbL 2 (µ-Cl) 2 Li(thf) 2 ] [L ϭ Me 2 Si(OtBu)(NtBu)], 2.247(5) and 2.225(5) Å , [23] implying a similar steric congestion.…”

Section: Resultssupporting

confidence: 60%

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Aryl Ether C−O Bond Activation by Organoamidolanthanoid(II) Complexes

Deacon

Forsyth

Scott

2000

Eur. J. Inorg. Chem.

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The reaction of ytterbium metal, HgPh2 and N‐(2‐methoxyphenyl)‐N‐(trimethylsilyl)amine (L1H) or N‐(2‐phenoxyphenyl)‐N‐(trimethylsilyl)amine (L2H) in tetrahydrofuran (thf) unexpectedly yielded the ytterbium(III) complexes [Yb(L1)2(μ‐OMe)]2 (1) and [Yb(L2)2(OPh)(thf)] (2), the structures of which were established by X‐ray crystallography. These are considered to be derived from C−O bond cleavage of the ligand aryl ether moiety by an initially formed YbII species, e.g. the thermally unstable, but crystallographically authenticated [Yb(L1)2(thf)2] (3), which was independently prepared from [Yb{N(SiMe3)2}2(thf)2] and L1H.

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Section: Resultssupporting

confidence: 60%

“…deprotonated 4,13-diaza-18-crown-6 [33] and Me 2 Si(OtBu)(NtBu). [23] Compounds 1 and 2 are unique examples of the products of OϪC(Ar) bond activation by a lanthanoid(II) centre. The ligands L 1 and L 2 also show the ability to stabilise heteroleptic lanthanoid(III) complexes with sterically undemanding co-ligands e.g.…”

Section: Resultsmentioning

confidence: 99%

Aryl Ether C−O Bond Activation by Organoamidolanthanoid(II) Complexes

Deacon

Forsyth

Scott

2000

Eur. J. Inorg. Chem.

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“…89 The complexed LiCl can easily be removed by refluxing the "ate" complex in pentane to give [Me 2 Si-(NtBu)(OtBu)] 2 YCl(THF). Subsequent alkylation with LiCH(SiMe 3 ) 2 afforded monomeric, unsolvated [Me 2 -Si(NtBu)(OtBu)] 2 YCH(SiMe 3 ) 2 , which was characterized by an X-ray structure determination (Y-C ) 255.8 (19) pm).…”

Section: Scheme 8 Preparation Of Bis(benzamidinato)scandium Alkyls Amentioning

confidence: 99%

Synthesis and Structural Chemistry of Non-Cyclopentadienyl Organolanthanide Complexes

2002

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Over the years one major challenge has remained in organolanthanide chemistry: the synthesis of homoleptic alkyl and aryl complexes. The simplest organometallic compounds of the rare earths are the species LnR 2 or LnR 3 with the rare earth metals in their common oxidation states Ln 2+ and Ln 3+ which imply the coordination of only two or three ligands to the metal center. This is usually insufficient to meet the lanthanides' demands of steric saturation through high coordination numbers.Hence for a long time, only indirect evidence could be found for the existence of simple homoleptic organolanthanide compounds; the isolation and characterization of compounds belonging to this class were first achieved recently using pentafluorophenyl for Ln 2+ derivatives 12 and very bulky alkyl ligands for Ln 3+ species. [13][14][15] Especially for alkyls, very little structural data are available for compounds without any trimethylsilyl-substituted ligands which generally ensure higher stability. But nevertheless, due to the difficulties of their synthesis and their high reactivity alkyls and aryls still represent an interesting class of compounds. 16 Homoleptic σ-Alkyl ComplexesShortly after the synthesis of the first divalent solvent-free Ln alkyl, [(Me 3 Si) 3 C] 2 Yb, 17 the Eu analogue was prepared similarly by the reaction of EuI 2 and KC(SiMe 3 ) 3 in benzene. 18 It also features the bent structure displayed by the Yb complex but with a slightly smaller C-Eu-C angle (C-Eu-C ) 136°, C-Yb-C ) 137°) and longer Eu-C bonds (Eu-C ) 261 pm, Yb-C ) 249/250 pm). Salt metathesis was then again applied successfully to synthesize the first divalent Sm alkyl, Sm[C(SiMe 3 ) 2 (SiMe 2 OMe)] 2 (THF) Frank T. Edelmann was born in Hamburg, Germany, in 1954. He studied chemistry from 1974 to 1979 at the University of Hamburg, where he obtained his Diplom in 1979 and doctoral degree in 1983. His Ph.D. thesis entitled "The chemistry of the tricarbonyl(fulvene) chromium complexes" was carried out under the supervision of Prof. Ulrich Behrens. This was followed by two years (1983−1985) of postdoctoral research as a Feodor Lynen Fellow of the Alexander-von-Humboldt Foundation in the groups of Professors Josef Takats (

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“…Subtraction values derived from the LnϪO distances (1.48Ϫ1.60 Å ) are significantly longer than those derived from organolanthanoid or halolanthanoid ether complexes [LnR 3 (ether) n : 1.34 Ϯ 0.05 Å ); [34] LnX 3 (THF) n : 1.39Ϫ1.44 Å ] [35] but the NdϪO distances are shorter than those [2.614(4)Ϫ2.740(4) Å ] in the related neodymium bidentate amide complex [Nd{Me 2 Si(OtBu)(NtBu)} 3 ]. [36] The ether fragments of [Nd{Me 2 Si(OtBu)(NtBu)} 3 ] and [Ln(L) 3 ] are bulkier than a simple ether ligand such as THF, and this may account for the long LnϪO distances, although the bond lengthening may also be an indication of general steric crowding in these complexes. The contraction of the subtraction values for the LnϪOPh bonds from La to Yb in the [Ln(L 2 ) 3 ]/[Ln(L 2 ) 3 ]·S n complexes ( Table 2) is contrary to the expected trend since the increase in steric crowding associated with the smaller size of the metal centre may result in metal-oxygen bond lengthening.…”

Section: 2e·(phme)]mentioning

confidence: 99%

“…Since all the LnCl 3 dissolved, it suggests that the heteroleptic species is formed initially, possibly stabilised as an ''ate'' complex such as A in Scheme 4. The formation of ''ate'' complexes has previously been observed for other bulky organoamidolanthanoids, for example [Yb{Me 2 Si(OtBu)(NtBu)} 2 (µ-Cl) 2 Li(THF) 2 ] [36] and [42] Therefore the rearrangement presumably occurs on addition of hexane [or for L 2 , Ln ϭ Yb, toluene (even with isolated LiL 2 ); for Ln ϭ La, also diethyl ether; Scheme 4 (iii)] with precipitation of LiCl and LnCl 3 or even LiLnCl 4 . This is contrary to the in situ [Ln(enЈ) 2 (µ-Cl)] 2 preparations where the heteroleptic derivatives were obtained from hexane.…”

Section: 2e·(phme)]mentioning

confidence: 99%

Solvent-Free Lanthanoid Complexes Derived From Chelation-Supported Organoamide Ligands

Deacon¹,

Forsyth²,

Scott³

2002

Eur. J. Inorg. Chem.

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Treatment of LnCl 3 with three molar equivalents of LiL [(L = N-(2-methoxyphenyl)-N-(trimethylsilyl)amide (L 1 ) or N-(2-phenoxyphenyl)-N-(trimethylsilyl)amide (L 2 )], generated in situ from LH and nBuLi, or with the isolated lithium complex [Li(L 1 )(OEt 2 )] 2 (for Ln = Yb) in THF afforded the solvent-free homoleptic complexes [Ln(L) 3 ] [Ln = Yb (1a), Er (1b), Sm (1c), Pr (1d), Nd (1e), L = L 1 ; Ln = Yb (2a), Y (2b), Sm (2c), Nd (2d), La (2e), L = L 2 ). With a 2:1 LiL (generated in situ) to LnCl 3 molar ratio, the solvent-free heteroleptic complexes [Ln(L) 2 (µ-Cl)] 2 were obtained for L = N,N-dimethyl-NЈ-trimethylsilylethane-1,2-diaminate (enЈ) [Ln = Yb (3a), Er (3b), Sm (3c), Nd (3d), La (3e)], but not for L 1 or L 2 , which gave [Ln(L) 3 ] [Ln = Yb (1a), Nd (1e), L = L 1 ; Ln = Yb (2a), Nd (2d), La (2e), L = L 2 ]. However, treatment of LnCl 3 with two molar equivalents of the isolated crystalline lithium salt [Li(L 1 )(-OEt 2 )] 2 in THF gave, for the heavier lanthanoids, the solventfree heteroleptic complexes [Ln(L 1 ) 2 (µ-Cl)] 2 [Ln = Yb (4a), Er (4b), Tb (4c)], although the homoleptic complex [Nd(L 1 ) 3 ] (1e)

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Alkoxysilylamide des Neodyms, Samariums und Ytterbiums: Viergliedrige anorganische Ringsysteme in der Lanthanidchemie

Cited by 23 publications

References 16 publications

Aryl Ether C−O Bond Activation by Organoamidolanthanoid(II) Complexes

Aryl Ether C−O Bond Activation by Organoamidolanthanoid(II) Complexes

Synthesis and Structural Chemistry of Non-Cyclopentadienyl Organolanthanide Complexes

Solvent-Free Lanthanoid Complexes Derived From Chelation-Supported Organoamide Ligands

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