Geminal dianions stabilized by phosphonium substituents

Harder, Sjoerd

doi:10.1016/j.ccr.2010.11.021

Cited by 53 publications

(29 citation statements)

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“…Another interesting feature of the crystal structure of 1-Li 2 concerns the coordination environments of the methandiide carbon atoms which strongly deviate from an ideal tetrahedron. As shown in Figure 7, C(1), S(1), P(1) and Li(1) are almost in one plane, while Li(2) is coordinating almost orthogonally to that plane with an Li-C-Li angle of 72.9 (2) • . This has also been observed in the crystal structure of methandiide C. On the basis of theoretical methods [26] this coordination mode can be explained by the two methandiide lone pairs populating two different orbitals, one of sp 2 -and the other of p-symmetry.…”

Section: Preparation Of Methanide 1-k and Methandiide 1-limentioning

confidence: 96%

“…Supplementary Materials: The following are available online at www.mdpi.com/2304-6740/4/4/40/s1, NMR spectra of all isolated compounds (Figures S1-S10) as well as crystallographic details for the compounds 1, 1-K and 1Li 2 (Tables S1-S7, Figures S11-S13).…”

Section: Discussionmentioning

confidence: 99%

“…In order to examine the influence of the electronic and steric properties of the iminophosphoryl group on the accessibility, reactivity and structure of methandiide 1-Li 2 we chose the protonated precursor 1 with a sterically demanding trimethylsilyl (TMS) group at the imino nitrogen atom, since this group has most often been used in other methandiide systems. To this end, the synthetic strategy outlined in Figure 3 was used.…”

Section: Synthesis Of the Protonated Precursormentioning

confidence: 99%

“…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].…”

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: Preparation Of Methanide 1-k and Methandiide 1-limentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Section: Synthesis Of the Protonated Precursormentioning

confidence: 99%

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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“…Complexes of methanediides (methandiides) that derive from P-oxidized bis(diphenylphosphino)methane species with electropositive metals have especially attracted widespread interest in recent years [2][3][4][5][6][7][8]. In these complexes, the dianionic bis(diphenylphosphoranyl)methanediide fragment A shows overall delocalization of the charge across the EPCPE fragment with a simplified charge distribution as shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Methanediide Formation via Hydrogen Elimination in Magnesium versus Aluminium Hydride Complexes of a Sterically Demanding Bis(iminophosphoranyl)methanediide

et al. 2017

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Reimagining theGrignard Reaction

Krieck

Westerhausen

2015

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Grignard reagents count as the most widely used reagents in organic and organometallic chemistry. These reagents are easily available and exhibit a broad reactivity spectrum depending on the nature of the organic groups (bulkiness, electronic properties, nucleophilicity, and denticity owing to peripheral functionalities), solvent, temperature, and additives such as other organometallic components. In recent years, this Grignard‐type chemistry has moved in diverse directions to solve various synthetic challenges. For classic Grignard reactions, the spectrum of applicable solvents has been extended to ionic liquids and even aqueous media. The reactivity of Grignard‐type reagents can be altered by adding more electropositive alkali metal salts, leading to heterobimetallic alkaline earth metallates, or by formation of alkaline earth metal metalates with more electronegative p‐block or transition metals. Species with magnesium‐metal bonds (the so‐called inorganic Grignard reagents) exhibit enormous reactivity as reducing reagents. An attractive alternative to magnesium‐based Grignards is offered by the heavier homologous organoalkaline earth metal derivatives that represent very reactive organometallics. Within the heavier homologous Grignard reagents, the calcium congeners represent the most attractive compounds. Calcium is nontoxic, globally abundant, easily accessible, and inexpensive. Its use is hampered by the enormous reactivity difference of the metal itself (requiring activation procedures before use) and the organometallics derived from it (often leading to ether degradation reactions). Therefore, alkylcalcium complexes usually are stabilized by bulky trialkylsilyl (kinetic stabilization by steric protection) or phenyl groups (electronic protection by delocalization of the anionic charge). The arylcalcium derivatives are easily available and exhibit persistence in ethereal media comparable to organolithium complexes.

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Geminal dianions stabilized by phosphonium substituents

Cited by 53 publications

References 95 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

Methanediide Formation via Hydrogen Elimination in Magnesium versus Aluminium Hydride Complexes of a Sterically Demanding Bis(iminophosphoranyl)methanediide

Reimagining theGrignard Reaction

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