Metal‐Ligand Cooperativity in a Methandiide‐Derived Iridium Carbene Complex

Weismann, Julia; Waterman, Rory; Gessner, Viktoria H.

doi:10.1002/chem.201503936

Cited by 23 publications

(16 citation statements)

References 114 publications

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“…A similar reactivity was observed with various silanes, for which the CH-IrSiR 3 intermediate was evidenced prior to R 3 SiH elimination to form complex 49. 137…”

Section: Group 9 Complexesmentioning

confidence: 99%

Geminal Dianions Stabilized by Main Group Elements

2019

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This review is dedicated to the chemistry of stable and isolable species that bear two lone pairs at the same C center, i.e. geminal dianions, stabilized by main group elements. Three cases can thus be considered: the gem dilithio derivative, for which the two substituents at C are neutral, the ylidiide derivatives, for which one substituent is neutral while the other is charged, and finally the geminal bisylides, for which the two substituents are positively charged. In this review the syntheses and electronic structures of the geminal dianions are presented, followed by the studies dedicated to their reactivity toward organic substrates and finally to their coordination chemistry and applications. Reactivity of doubleylides towards organic compounds. 4.4. Coordination chemistry of double ylides to metallic species. 4.4.1. Coordination to Group 2 Metals. 4.4.2. Coordination to Actinides: Uranium Complexes 4.4.3. Coordination to Group 4 Metals: Zirconium Complexes 4.4.4. Coordination to Group 6 Metals: Tungsten Complexes 4.4.5. Coordination to Group 7 Metals: Manganese and Rhenium Complexes 4.4.6. Coordination to Group 8 Metals: Iron Complexes 4.4.7. Coordination to Group 9 Metals: Rhodium and Iridium Complexes 4.4.8. Coordination to Group 10 Metals 4.4.9. Coordination to Group 11 (Coinage) Metals 4.4.10. Coordination to Group 12 Metals 4.5. Reactivity of double ylides towards main group elements. 4.5.1. Group 13 4.5.2. Group 14 4.5.3. Group 15 4.5.4. Group 16 4.5.5. Group 17 4.6. Carbodicarbenes 4.6.1. Synthesis 4.6.2. Reactivity 4.6.3. Coordination chemistry 4.6.4. Reactivity with main group elements 5. Conclusion 6. Acknowledgements 7. References lengths in complexes [(7)Mg(THF)] 2 and [(14)Mg(THF) 3 ] at 2.156(5)Å and 2.113(4)Å resp. are as expectedly significantly shorter than the ones measured in the dimers [(6a)Mg] 2 and [(10)Mg] 2 at 2.225(2)Å (av.) and 2.267(3)Å (av.). Electronic structureThe question of the nature of the bond between the AE metal and C was addressed. Harder et al.performed a DFT study first on models of [(6a)Ca] 2 and [(6f)Ca] where H atoms were considered in place of the real phenyl groups at P and groups (SiMe 3 and Ar resp.) at N. 49 In the case of the monomeric complex [(6f)Ca], the solvent molecules were not taken into account. Not surprising in light of the difference of electronegativity of the elements, the charge at C varied between -1.623 (monomer) and -1.847 (dimer) whereas charge at Ca varied between +1.760 (monomer) and +1.821 (dimer). The Ca-C bond was thus described as highly ionic. The calculations with the full dimeric system were carried out, and a slightly reduced charge was calculated at C (-1.778). The NPA charges were also compared to the ones in neutral 6aH 2 and the [Ca(6aH) 2 ] complex. Expectedly the charge at C goes from -1.079 to -1.409 to -1.778 (in 6aH2, [Ca(6aH) 2 ], [Ca(6a)] 2 resp.). The charge at N also increases (-1.474 to -1.580 to -1.665 resp.) upon deprotonation at C. Conversely, the charge at P varies but to a small extent (+1.747 to +1.727 to +1.7...

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“…A similar reactivity was observed with various silanes, for which the CH-IrSiR 3 intermediate was evidenced prior to R 3 SiH elimination to form complex 49. 137…”

Section: Group 9 Complexesmentioning

confidence: 99%

Geminal Dianions Stabilized by Main Group Elements

2019

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“…Instead, cleavage of the H 2 bond from Int II proceeds through direct proton transfer to the pincer alkyl carbon ( TS II , Δ G ≠ =23.7 kcal mol −1 ), furnishing the syn ‐isomer of 7 (Δ G =−11.9 kcal mol −1 ). The alternative stepwise mechanism, [27] that is, oxidative addition of H 2 followed by proton transfer onto the pincer carbon atom, was found to be kinetically less favourable (see ESI). Subsequent C‐H reductive elimination (Δ G ≠ =18.6 kcal mol −1 ) generates Int III (Δ G =−4.8 kcal mol −1 ).…”

Section: Resultsmentioning

confidence: 99%

Access to and Reactivity of Fe⁰, Fe^−I, Fe^I, and Fe^II PC_carbeneP Pincer Complexes

et al. 2021

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Despite their promising metal–ligand cooperative reactivity, PCcarbeneP pincer ligands are rarely reported for first‐row transition‐metal centres. Using a dehydration methodology, we report access to an Fe0 PCcarbeneP pincer complex (1) that proceeds via an isolated α‐hydroxylalkyl hydrido complex (3). Reversible carbonyl migration to the carbene position in 1 is found to allow coordination chemistry and E−H bond addition (E=H, B, Cl) across the iron–carbene linkage, representing a unique mechanism for metal–ligand cooperativity. The PCcarbeneP pincer ligand is also found to stabilize formal FeII, FeI, and Fe−I oxidation states, as demonstrated with synthesis and characterization of the complexes [11‐X][BArF20] (X=Br, I), 12, and K[13]. Compound K[13] is found to be highly reactive, and abstracts hydrogen from a range of aliphatic C−H sources. Computational analysis by DFT suggests that the formal FeI and Fe−I complexes contain significant carbene radical character. The ability of the PCcarbeneP ligand scaffold to partake in metal–ligand cooperativity and to support a range of iron oxidation states renders it as potentially useful in many catalytic applications.

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“…group also gave way to the formation of transition-metal complexes with open coordination-sides [27][28][29]. Besides their applicability in carbene complex chemistry, methandiides are also interesting reagents because of their structural properties.…”

Section: Introductionmentioning

confidence: 99%

“…The unsymmetrical methandiide C was found to form a complex molecular structure, which however also showed a strong deviation from the ideal tetrahedral geometry of carbon [26]. group also gave way to the formation of transition-metal complexes with open coordination-sides [27][28][29]. Besides their applicability in carbene complex chemistry, methandiides are also interesting reagents because of their structural properties.…”

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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Metal‐Ligand Cooperativity in a Methandiide‐Derived Iridium Carbene Complex

Cited by 23 publications

References 114 publications

Geminal Dianions Stabilized by Main Group Elements

Geminal Dianions Stabilized by Main Group Elements

Access to and Reactivity of Fe⁰, Fe^−I, Fe^I, and Fe^II PC_carbeneP Pincer Complexes

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

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Metal‐Ligand Cooperativity in a Methandiide‐Derived Iridium Carbene Complex

Cited by 23 publications

References 114 publications

Geminal Dianions Stabilized by Main Group Elements

Geminal Dianions Stabilized by Main Group Elements

Access to and Reactivity of Fe0, Fe−I, FeI, and FeII PCcarbeneP Pincer Complexes

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

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Access to and Reactivity of Fe⁰, Fe^−I, Fe^I, and Fe^II PC_carbeneP Pincer Complexes