Mixed AggregAte (MAA): A Single Concept for All Dipolar Organometallic Aggregates. 1. Structural Data

Harrison‐Marchand, Anne; Mongin, Florence

doi:10.1021/cr300295w

Cited by 171 publications

(76 citation statements)

References 812 publications

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“…Organolithium reagents were titrated against diphenylacetic acid prior use. 1 H, 7 Li, 13 C, 31 P NMR spectra were recorded on Avance-500, Avance-400 or Avance-300 spectrometers (Bruker Biospin GmbH, Rheinstetten, Germany) at 22 • C if not stated otherwise. All values of the chemical shift are in ppm regarding the δ-scale.…”

Section: General Proceduresmentioning

confidence: 99%

“…Besides their applicability in carbene complex chemistry, methandiides are also interesting reagents because of their structural properties. Analogous to simple organolithium reagents [30][31][32], structure formation is dominated by the presence or absence of additional donor functions within the molecule. Non-functionalized methandiides typically form polymeric structures to complete the coordination sphere of lithium, such as in the case of parent dilithiomethane, H 2 CLi 2 [33], or dilithiated fluorene D (Figure 2) [20].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and Characterization of a Sulfonyl- and Iminophosphoryl-Functionalized Methanide and Methandiide

Feichtner

Gessner

2016

Inorganics

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The synthesis of [H 2 C(PPh 2 =NSiMe 3 )(SO 2 Ph)] (1) and its mono-and dimetalation are reported. Due to the strong anion-stabilizing abilities of the iminophosphoryl and the sulfonyl group monometalation to 1-K and dimetalation to 1-Li 2 proceed smoothly with potassium hydride and methyllithium, respectively. Both compounds could be isolated in high yields and were characterized by NMR spectroscopy as well as XRD analysis. The methanide 1-K forms a coordination polymer in the solid state, while in case of the methandiide a tetrameric structure is observed. The latter features an unusual structural motif consisting of two (SO 2 Li) 2 eight-membered rings, which are connected with each other via the methandiide carbon atoms and additional lithium atoms. With increasing metalation a contraction of the P-C-S linkage is observed, which is well in line with the increased charge at the central carbon atom and involved electrostatic interactions.Keywords: methandiides; lithium; potassium; molecular structures BackgroundIn the past 20 years, methandiides with a doubly metalated carbon atom (R 2 CM 2 with M mostly being Li) have attracted intense research interest in organometallic chemistry. This is mainly due to their applicability as ligands for the preparation of carbene-type complexes by simple salt metathesis reactions [1][2][3]. Thereby, methandiides revealed to be highly efficient ligand systems stabilizing a variety of carbene complexes with main group metals [4][5][6][7], early and late transition metals [8][9][10][11][12] as well as lanthanides and actinides [13][14][15][16]. The first dilithium compound, which was employed in this chemistry, was the bis(iminophosphorano) system {Li 2 (bipm TMS )} 2 (A, bipm TMS =C(PPh 2 NSiMe 3 ) 2 ), which was simultaneously reported by the groups of Cavell and Stephan in 1999 (Figure 1) [17,18]. Unlike all other methandiides reported before [19][20][21], A was found to be conveniently accessible by double deprotonation and isolable in high yields, thus allowing its application in carbene complex synthesis [22]. The high stability and facile synthesis of A can be explained by the strong anion-stabilizing ability of the P(V) moieties as well as the additional nitrogen donor side-arms, which efficiently coordinate lithium to form stable complexes. Analogously, the corresponding thiophosphoryl system B reported by Le Floch also proved to be a stable and powerful ligand system [23][24][25]. More recently, our group has focused on non-DPPM derived methandiides, to expand the carbene chemistry of these compounds also to ligands with other substituents. The dilithium compound C with a sulfonyl functionality turned out to be easily accessible and similarly stable than the bis(phosphonium)-substituted systems [26]. The weaker coordination ability of the sulfonyl group also gave way to the formation of transition-metal complexes with open coordination-sides [27][28][29].

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Section: General Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of a Sulfonyl- and Iminophosphoryl-Functionalized Methanide and Methandiide

Feichtner

Gessner

2016

Inorganics

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“…Alkyl compounds of lithium play an important role in organometallic chemistry [1][2][3][4][5]. This group of compounds is therefore well investigated, which can also be attributed to their accessibility and solubility in a wide range of organic solvents.…”

Section: Introductionmentioning

confidence: 99%

[Bis(Trimethylsilyl)Methyl]Lithium and -Sodium: Solubility in Alkanes and Complexes with O- and N- Donor Ligands

2017

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Abstract:In contrast to alkyl compounds of lithium, which play an important role in organometallic chemistry, the corresponding heavier alkali metal compounds are less investigated. These compounds are mostly insoluble in inert solvents or undergo solvolysis in coordinating solvents due to their high reactivity. An exception from this typical behavior is demonstrated by bis(trimethylsilyl) methylsodium. This study examines alkane solutions of bis(trimethylsilyl)methyllithium and -sodium by NMR spectroscopic and cryoscopic methods. In addition, structural studies by X-ray crystallography of the corresponding compounds coordinated by O-and N-ligands (tetrahydrofuran and tetramethylethylenediamine) present possible structural motifs of the uncoordinated compounds in solution.

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“…6 Magnesiates have recently received a high degree of attention from the synthetic chemist in a large part due to the work of Knochel. 19 The structure of the pioneering Wittig's lithium magnesiate was elucidated by Weiss by adding TMEDA to the magnesiate mixture. These lithium magnesiate reagents have been coined as 'turbo Grignard' [with general formulae RMgCl·LiCl and (NR 2 )MgCl·LiCl respectively].…”

Section: Introductionmentioning

confidence: 99%

Solid state and solution studies of lithium tris(n-butyl)magnesiates stabilised by Lewis donors

et al. 2015

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Several Lewis base adducts of the synthetically important lithium tris(n-butyl)magnesiate LiMg((n)Bu)3 have been prepared and structurally characterised. The complexes were prepared by a co-complexation approach i.e., by combining the monometallic (n)BuLi and (n)Bu2Mg reagents in hydrocarbon solution before adding a molar equivalent of a donor molecule (a bidentate amine, tridentate amine or cyclic ether). The lithium magnesiates all adopt variants of the "Weiss motif" structure, i.e., contacted ion pair dimers with a linear arrangement and metals connected by butyl anions, where tetrahedral magnesium ions are in the central positions and the lithiums occupy the outer region, solvated by a neutral Lewis donor [(donor)Li(μ-(n)Bu)2Mg(μ-(n)Bu)2Mg(μ-(n)Bu)2Li(donor)]. When TMPDA, PMDETA or (R,R)-TMCDA [TMPDA = N,N,N'N'-tetramethylpropanediamine; PMDETA = N,N,N',N'',N''-pentamethyldiethylenetriamine; and (R,R)-TMCDA = (R,R)-N,N,N',N'-tetramethylcyclohexane-1,2-diamine], are employed, dimeric tetranuclear lithium magnesiates are produced. Due to the tridentate nature of the ligand, the PMDETA-containing structure (2) has an unusual 'open'-motif. When TMEDA (TMEDA = N,N,N',N'-tetramethylethylenediamine) is employed, a n-butoxide-containing complex [(TMEDA)Li(μ-(n)Bu)(μ-O(n)Bu)Mg2((n)Bu)2(μ-(n)Bu)(μ-O(n)Bu)Li(donor)] has been serendipitously prepared and adopts a ladder conformation which is commonly observed in lithium amide chemistry. This complex has also been prepared using a rational methodology. When 1,4-dioxane is employed, the donor stitches together a polymeric array of tetranuclear dimeric units (6). The hydrocarbon solution structures of the compounds have been characterised by (1)H, (7)Li, (13)C NMR spectroscopy; 2 has been studied by variable temperature and DOSY NMR.

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Mixed AggregAte (MAA): A Single Concept for All Dipolar Organometallic Aggregates. 1. Structural Data

Cited by 171 publications

References 812 publications

Synthesis and Characterization of a Sulfonyl- and Iminophosphoryl-Functionalized Methanide and Methandiide

Synthesis and Characterization of a Sulfonyl- and Iminophosphoryl-Functionalized Methanide and Methandiide

[Bis(Trimethylsilyl)Methyl]Lithium and -Sodium: Solubility in Alkanes and Complexes with O- and N- Donor Ligands

Solid state and solution studies of lithium tris(n-butyl)magnesiates stabilised by Lewis donors

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