Chelates formed by a constrained bis(diphenylphosphino)xylene; the crystal structures of [FeCl2(anphos)] and [RhCl(CO)(anphos-monoxide)]

Higham, Lee J.; Middleton, Ann J.; Heslop, Katie; Pringle, Paul G.; Barber, A; Orpen, A. Guy

doi:10.1016/j.jorganchem.2004.06.022

Cited by 9 publications

(2 citation statements)

References 17 publications

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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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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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“…A search in the Cambridge Structural Database [MOGUL Version 1.7; Allen (2002)] yielded a few hits, e.g. GAWDUD (Hermes & Girolami, 1988), RADMEP (Higham et al, 2004) and WOFSUF (Renkema et al, 1999), all with tetrahedrally coordinated iron. During our efforts to synthesize new phosphorus-bridged and phosphine-substituted multinuclear iron complexes, the novel title compound, (I), was isolated as a by-product.…”

Section: Commentmentioning

confidence: 99%

Dichlorobis(triphenylphosphine)iron(II)

2005

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Synthesis of New Diphosphine Ligands and their Application in Pd‐Catalyzed Alkoxycarbonylation Reactions

Pews‐Davtyan¹,

Fang²,

Jackstell³

et al. 2014

Chemistry An Asian Journal

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Carbocyclic and N-heterocyclic analogues of the industrially applied ligand bis(di-tert-butylphosphinomethyl)benzene (1) have been synthesized in moderate to very good yields. The new ligands are based on benzene, tetralin, lutidine, pyrazine, quinoxaline, and maleimide backbones. Electronic and steric variations of the phosphorous donor sites were performed. As a benchmark reaction, the palladium-catalyzed methoxycarbonylation of 1-octene has been tested. Ester yields up to 64% and high linear selectivities up to 92% were achieved.

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Chelates formed by a constrained bis(diphenylphosphino)xylene; the crystal structures of [FeCl2(anphos)] and [RhCl(CO)(anphos-monoxide)]

Cited by 9 publications

References 17 publications

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

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

Dichlorobis(triphenylphosphine)iron(II)

Synthesis of New Diphosphine Ligands and their Application in Pd‐Catalyzed Alkoxycarbonylation Reactions

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