Group IV Coordination Chemistry of a Tetradentate Redox‐Active Ligand in Two Oxidation States

Blackmore, Karen J.; Lal, Neetu; Ziller, Joseph W.; Heyduk, Alan F.

doi:10.1002/ejic.200800945

Cited by 50 publications

(45 citation statements)

References 28 publications

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“…The application of redox-active quinone-containing ligands for Ru-mediated water oxidation catalysis was reported by Tanaka and co-workers. The catalyst consists of two terpyridine fragments anchored to a dinucleating rigid anthracene scaffold amenable to hosting two ruthenium metal centers, with one redox-active quinone ligand as well as a hydroxy fragment per Ru (33,Scheme 17). 42 The mechanism of water oxidation using this catalyst has been subject to extensive research in the following years, both experimentally and theoretically.…”

Section: (B) Late Transition Metalsmentioning

confidence: 99%

New avenues for ligand-mediated processes – expanding metal reactivity by the use of redox-active catechol, o-aminophenol and o-phenylenediamine ligands

2015

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Redox-active ligands have evolved from being considered spectroscopic curiosities - creating ambiguity about formal oxidation states in metal complexes - to versatile and useful tools to expand on the reactivity of (transition) metals or to even go beyond what is generally perceived possible. This review focusses on metal complexes containing either catechol, o-aminophenol or o-phenylenediamine type ligands. These ligands have opened up a new area of chemistry for metals across the periodic table. The portfolio of ligand-based reactivity invoked by these redox-active entities will be discussed. This ranges from facilitating oxidative additions upon d(0) metals or cross coupling reactions with cobalt(iii) without metal oxidation state changes - by functioning as an electron reservoir - to intramolecular ligand-to-substrate single-electron transfer to create a reactive substrate-centered radical on a Pd(ii) platform. Although the current state-of-art research primarily consists of stoichiometric and exploratory reactions, several notable reports of catalysis facilitated by the redox-activity of the ligand will also be discussed. In conclusion, redox-active ligands containing catechol, o-aminophenol or o-phenylenediamine moieties show great potential to be exploited as reversible electron reservoirs, donating or accepting electrons to activate substrates and metal centers and to enable new reactivity with both early and late transition as well as main group metals.

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Section: (B) Late Transition Metalsmentioning

confidence: 99%

New avenues for ligand-mediated processes – expanding metal reactivity by the use of redox-active catechol, o-aminophenol and o-phenylenediamine ligands

2015

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“…The solvents were dried and deoxygenated by distillation over Na/K alloy/benzophenone. 6,6′‐[1,2‐Phenylenebis(azanediyl)]bis(2,4‐di‐ tert ‐butylphenol) (H 4 L) was prepared according to the procedure described in the literature [13] . The NMR spectra of 1 were obtained in CD 2 Cl 2 or THF solution at room temperature with a Bruker Avance III 500 FT spectrometer with operating frequencies of 500.03, 150.76, 125.73, 50.67 MHz for 1 H, 125 Te, 13 C, and 15 N nuclei, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…For the ligand L bearing the o ‐phenylene bridge (Scheme 2), the oxidation states from 0 to −4 are accessible, which makes it an efficient electron reservoir. For this ligand, complexes with transition metals Ti, [13, 14] Zr, [14, 15] Hf, [13] Mo, [16] W, [17] Mn, [18] Cu, [19] and Zn, [19] as well as Sn [20] as the only post‐transition metal, are known. Catalytic properties of some of these complexes were studied.…”

Section: Introductionmentioning

confidence: 99%

A Sterically Hindered Derivative of 2,1,3‐Benzotelluradiazole: A Way to the First Structurally Characterised Monomeric Tellurium–Nitrogen Radical Anion

Петров

Kadilenko

Sukhikh

et al. 2020

Chemistry A European J

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“…6 Acyclic tetradentate ligands of linear chain afford complexes with stereochemistries which depend upon the rigidity of the ligand. More rigid ligands display planar 7 or tetrahedral 8 coordinations, whereas flexible molecules and anions orientate their donor atoms to stabilize sixcoordinate geometrical isomers (I, 9 II, 10 and III 11 in Chart 1). The chain of the acyclic tetradentate ligands of branched chain can be bifurcated at a donor atom, 12 at an atom other than a donor atom, 13 or a bridging group links two bidentate moieties.…”

Section: Introductionmentioning

confidence: 99%

Osmium(II) Complexes Containing a Dianionic CCCC-Donor Tetradentate Ligand

et al. 2016

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The preparation of osmium(II) complexes containing a C C 6 H 4 ,C BzIm ,C BzIm ,C C 6 H 4-tetradentate ligand with a-CH 2 CH 2link between the benzimidazolidene (BzIm) groups is described and the influence of the link on their structures and emissive properties is analyzed. The hexahydride complex OsH 6 (P i Pr 3) 2 (1) reacts with 1,1'-diphenyl-3,3'-ethylenedibenzimidazolium bromide in dimethylformamide to afford OsBr{κ 3-C,C,C-(C 6 H 4-BzIm-CH 2 CH 2-BzIm-Ph)}(CO)(P i Pr 3) 2 (2), as a result of the direct metalation of both benzimidazolium moieties of the salt, the ortho-CH bond activation of a phenyl substituent, and the carbonylation of the metal center by action of the solvent. Treatment of 2 with Na[BH 4 ] leads to the hydride derivative OsH{κ 3-C,C,C-(C 6 H 4-BzIm-CH 2 CH 2-BzIm-Ph)}(CO)(P i Pr 3) 2 (3) which evolves into Os{κ 4-C,C,C,C-(C 6 H 4-BzIm-CH 2 CH 2-BzIm-C 6 H 4)}(CO)(P i Pr 3) 2 (4) as a consequence of the assisted C-H bond activation of the second phenyl substituent. The use of dimethylsulfoxide instead of dimethylformamide allows the generation of the tetradentate ligand in one pot. Stirring of dimethylsulfoxide solutions of 1 leads to Os{κ 4-C,C,C,C-(C 6 H 4-BzIm-CH 2 CH 2-BzIm-C 6 H 4)}(DMSO) 2 (5). The solvent molecules of 5 can be displaced by 1,2bis(diphenylphosphino)ethylene (bdppe), 1,2-bis(diphenylphosphino)benzene (dppbz) and tetrafluorobenzobarrelene (TFB) to yield the [4+2]-derivatives Os{κ 4-C,C,C,C-(C 6 H 4-BzIm-CH 2 CH 2-BzIm-C 6 H 4)}L 2 (L 2 = bdppe (6), dppbz (7), TFB (8)). The X-ray structures of 4, 6 and 7 reveal that in these compounds, the tetradentate ligand adopts a mer three-planar disposition of a phenyl and two benzimidazolidene groups with the other phenyl group situated in a perpendicular direction trans-disposed to L. The reason of this preference is electronic. Thus, the stereochemistry of 7 is the same as that found in the related complexes Os{κ 2-C,C-(MeBzIm-C 6 H 4)} 2 (dppbz) (13) and Os{κ 2-C,C-(MeBzIm*-C 6 H 4)} 2 (dppbz) (14) containing two free orthometalated Nphenylbenzimidazolidene ligands. Complexes 7, 13 and 14 are phosphorescent. The first of them shows emissions narrower and bluer than those of 13 and 14.

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Group IV Coordination Chemistry of a Tetradentate Redox‐Active Ligand in Two Oxidation States

Cited by 50 publications

References 28 publications

New avenues for ligand-mediated processes – expanding metal reactivity by the use of redox-active catechol, o-aminophenol and o-phenylenediamine ligands

New avenues for ligand-mediated processes – expanding metal reactivity by the use of redox-active catechol, o-aminophenol and o-phenylenediamine ligands

A Sterically Hindered Derivative of 2,1,3‐Benzotelluradiazole: A Way to the First Structurally Characterised Monomeric Tellurium–Nitrogen Radical Anion

Osmium(II) Complexes Containing a Dianionic CCCC-Donor Tetradentate Ligand

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