Group 8 Transition Metal Complexes of the Tripodal Triphosphino Ligands PhSi(CH2PR2)3 (R = Ph, iPr)

Neumeyer, Felix; Lipschutz, Michael I.; Tilley, T. Don

doi:10.1002/ejic.201301074

Cited by 12 publications

(20 citation statements)

References 22 publications

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“…Although the overall structure of 3 is in line with previous reports, [27,28] a significant difference can be observed when compared to FeCl 2 (SciOPP). [8] Complex 3 has a significantly larger PÀFeÀP bite angle (91.058) compared to FeCl 2 (SciOPP) (80.638).…”

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confidence: 90%

Towards Iron-Catalyzed Sonogashira Cross-Coupling Reactions

et al. 2016

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Herein we report on the selective iron‐catalyzed cross‐coupling reaction of terminal phenylacetylenes with iodo‐aryl derivatives to afford the respective coupling products in the presence of 10 mol% FeCl2(bdmd) and 10 mol% [Cu(CH3CN)4]BF4 (bdmd=bis((diphenylphosphanyl)methyl)diphenylsilane). The yields are moderate to good in 1,4‐dioxane or DMF. This is the first example of a well‐defined and fully analysed ferrous complex acting as a precatalyst in Sonogashira cross‐coupling reactions. Notably, FeCl2(bdmd) is compatible with reactive substituents such as carbonyl‐, carboxyl‐, hydroxy‐, and amino‐groups, which allows for an effective cross‐coupling reaction in the presence of such functional groups.

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confidence: 90%

Towards Iron-Catalyzed Sonogashira Cross-Coupling Reactions

et al. 2016

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“…The synthesis of tripodal Si-triphos Ph (1a,b) and P-triphos Ph (1c) ligands was achieved in a modular two-step procedure based on publications by the groups of Tilley, 13 LaBelle, 14 Gramlich, 15 and A ́lvarez. 16 Deprotonation of the methyl group of MePPh 2 , using n-BuLi and N,N,N′,N′-tetramethylethylenediamine (TMEDA), resulted in the formation of the Ph 2 PMeLi−TMEDA complex, which was directly used in a nucleophilic substitution.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Application of Hetero-Triphos Ligands in the Selective Ruthenium-Catalyzed Transformation of Carbon Dioxide to the Formaldehyde Oxidation State

et al. 2019

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Due to the increasing demand for formaldehyde as a building block in the chemical industry as well as its emerging potential as feedstock for biofuels in the form of dimethoxymethane and the oxymethylene ethers produced therefrom, the catalytic transformation of carbon dioxide to the formaldehyde oxidation state has become a focus of interest. In this work, we present novel ruthenium complexes with hetero-triphos ligands, which show high activity in the selective transformation of carbon dioxide to dimethoxymethane. We substituted the apical carbon atom in the backbone of the triphos ligand platform with silicon or phosphorus and optimized the reaction conditions to achieve turnover numbers as high as 685 for dimethoxymethane. The catalytic systems could also be tuned to preferably yield methyl formate with turnover numbers of up to 1370, which in turn can be converted into dimethoxymethane under moderate conditions.

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“…To date, the only structurally characterized monomeric 1:1 ferrous adduct incorporating these ligands is FeCl 2 (SciOPP), developed by Nakamura and co-workers. Because structurally characterized complexes of the type FeCl 2 (PP) (PP = bidentate phosphine ligation) have been widely reported, − we envisioned an isostructural series of four-coordinate ferrous dihalides as a set of model compounds to begin to systematically discern how different structural characteristics of the chelating phosphine affect the overall electronic structure and bonding within their coordination compounds at the iron(II) level. While the preparation of FeCl 2 (dpbz) has been summarized in the literature using stoichiometric equivalents of dpbz and FeCl 2 , no solid state characterization of this adduct has been reported.…”

Section: Results and Analysismentioning

confidence: 99%

Electronic Structure and Bonding in Iron(II) and Iron(I) Complexes Bearing Bisphosphine Ligands of Relevance to Iron-Catalyzed C–C Cross-Coupling

et al. 2015

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Chelating phosphines are effective additives and supporting ligands for a wide array of iron-catalyzed cross-coupling reactions. While recent studies have begun to unravel the nature of the in situ-formed iron species in several of these reactions, including the identification of the active iron species, insight into the origin of the differential effectiveness of bisphosphine ligands in catalysis as a function of their backbone and peripheral steric structures remains elusive. Herein, we report a spectroscopic and computational investigation of well-defined FeCl2(bisphosphine) complexes (bisphosphine = SciOPP, dpbz, tBudppe, or Xantphos) and known iron(I) variants to systematically discern the relative effects of bisphosphine backbone character and steric substitution on the overall electronic structure and bonding within their iron complexes across oxidation states implicated to be relevant in catalysis. Magnetic circular dichroism (MCD) and density functional theory (DFT) studies demonstrate that common o-phenylene and saturated ethyl backbone motifs result in small but non-negligible perturbations to 10Dq(Td) and iron–bisphosphine bonding character at the iron(II) level within isostructural tetrahedra as well as in five-coordinate iron(I) complexes FeCl(dpbz)2 and FeCl(dppe)2. Notably, coordination of Xantphos to FeCl2 results in a ligand field significantly reduced relative to those of its iron(II) partners, where a large bite angle and consequent reduced iron–phosphorus Mayer bond orders (MBOs) could play a role in fostering the unique ability of Xantphos to be an effective additive in Kumada and Suzuki–Miyaura alkyl–alkyl cross-couplings. Furthermore, it has been found that the peripheral steric bulk of the SciOPP ligand does little to perturb the electronic structure of FeCl2(SciOPP) relative to that of the analogous FeCl2(dpbz) complex, potentially suggesting that differences in the steric properties of these ligands might be more important in determining in situ iron speciation and reactivity.

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Group 8 Transition Metal Complexes of the Tripodal Triphosphino Ligands PhSi(CH₂PR₂)₃ (R = Ph, iPr)

Abstract: A series of group 8 transition metal complexes of new tridentate phosphine ligands with Fe, Ru, and Os were prepared. The new complexes were characterized by multinuclear NMR spectroscopy and X‐ray crystallography.

Cited by 12 publications

References 22 publications

Towards Iron-Catalyzed Sonogashira Cross-Coupling Reactions

Towards Iron-Catalyzed Sonogashira Cross-Coupling Reactions

Application of Hetero-Triphos Ligands in the Selective Ruthenium-Catalyzed Transformation of Carbon Dioxide to the Formaldehyde Oxidation State

Electronic Structure and Bonding in Iron(II) and Iron(I) Complexes Bearing Bisphosphine Ligands of Relevance to Iron-Catalyzed C–C Cross-Coupling

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