Low-potential nickel(III,II) complexes: new systems based on tetradentate amidate-thiolate ligands and the influence of ligand structure on potentials in relation to the nickel site in [NiFe]-hydrogenases

Krüger, Hans‐Jörg; Peng, Gang; Holm, R. H.

doi:10.1021/ic00004a025

Cited by 259 publications

(262 citation statements)

References 6 publications

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“…[16] In contrast, complexes of the type [Ni II N 2 S 2 ] 2À containing anionic amide N-donors exhibit reversible electrochemistry that ultimately leads to the generation of Ni III centers that can be detected as their pyridine adducts by EPR spectroscopy in solution at low temperature. [17][18][19] There is one example of a synthetic complex containing a mixed amine/amide thiolate coordination sphere [Me 4 …”

Section: Introductionmentioning

confidence: 99%

“…[17,18,37,38] The Ni(1) À N(1) and Ni(1) À N(2) distances (ca. 1.89 , Table 2) are typical of those observed for Ni II À NA C H T U N G T R E N N U N G (imine) bonds.…”

mentioning

confidence: 99%

“…[19,36,[38][39][40][41][42][43][44][45][46] The dihedral angles between the planes defined by S(1)-Ni(1)-S (2) 2 Ni bridge. [18] The cyclic voltammogram of 2 shows ( Figure 5) similar behavior and exhibits a reversible one-electron oxidation process at E 1/2 = 0.10 V versus Fc + /Fc at 293 K that loses reversibility at temperatures below 253 K. In addition, a second, oxidation process is observed for 2 at E p a = 0.93 V versus Fc + /Fc at 293 K. By contrast, 3 and 4 do not exhibit any reversible redox processes; instead, a series of temperature-independent oxidative processes at E p a = 0.29, 0.60 and 0.88 V versus Fc + /Fc for 3 and E p a = 0.41 V versus Fc + /Fc for 4 were noted (see Figure S3 in the Supporting Information). This observation suggests that the incorporation of tBu groups within the ligand frameworks in 1 and 2 stabilizes the one-electron oxidized species, 1 + and 2 + relative to the 3 + and 4 + under ambient conditions.…”

mentioning

confidence: 99%

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Molecular and Electronic Structures of One‐Electron Oxidized Ni^II–(Dithiosalicylidenediamine) Complexes: Ni^III–Thiolate versus Ni^II–Thiyl Radical States

Stenson

Board

Marín-Becerra

et al. 2008

Chemistry A European J

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The dithiosalicylidenediamine Ni II complexes [Ni(L)] (R=tBu, R'=CH2C(CH3)2CH2 1, R'=C6H4 2; R=H, R'=CH2C(CH3)2CH2 3, R'=C6H4 4) have been prepared by transmetallation of the tetrahedral complexes [Zn(L)] (R=tBu, R'=CH2C(CH3)2CH2 7, R'=C6H4 8; R=H, R'=CH2C(CH3)2CH2 9, R'=C6H4 10) formed by condensation of 2,4-di-R-thiosalicylaldehyde with diamines H2N-R'-NH2 in the presence of Zn II salts. The diamagnetic mononuclear complexes [Ni(L)] show a distorted square-planar N2S2 coordination environment and have been characterized by 1H- and 13C NMR and UV/Vis spectroscopies and by single-crystal X-ray crystallography. Cyclic voltammetry and coulombic measurements have established that complexes 1 and 2, incorporating tBu functionalities on the thiophenolate ligands, undergo reversible one-electron oxidation processes, whereas the analogous redox processes for complexes 3 and 4 are not reversible. The one-electron oxidized species, 1+ and 2+, can be generated quantitatively either electrochemically or chemically with 70 % HClO4. EPR and UV/Vis spectroscopic studies and supporting DFT calculations suggest that the SOMOs of 1+ and 2+ possess thiyl radical character, whereas those of 1(py)2 + and 2(py)2 + possess formal Ni III centers. Species 2+ dimerizes at low temperature, and an X-ray crystallographic determination of the dimer [(2)2](ClO4)2.2 CH2Cl2 confirms that this dimerization involves the formation of a S-S bond (S...S=2.202(5) A).

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Section: Introductionmentioning

confidence: 99%

“…[17,18,37,38] The Ni(1) À N(1) and Ni(1) À N(2) distances (ca. 1.89 , Table 2) are typical of those observed for Ni II À NA C H T U N G T R E N N U N G (imine) bonds.…”

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confidence: 99%

mentioning

confidence: 99%

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Molecular and Electronic Structures of One‐Electron Oxidized Ni^II–(Dithiosalicylidenediamine) Complexes: Ni^III–Thiolate versus Ni^II–Thiyl Radical States

Stenson

Board

Marín-Becerra

et al. 2008

Chemistry A European J

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“…[6][7][8][9] These characteristics are contrasted to the classical ligands of organometallic chemistry, diphosphines and diimines. The results are presented herein along with an organometallic reaction principle that models steps in acetyl coA synthase as well as CO/olefin copolymerization catalysis.…”

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confidence: 99%

N₂S₂Ni Metallothiolates as a Class of Ligands that Support Organometallic and Bioorganometallic Reactivity

et al. 2005

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That Cys-X-Cys tripeptide linkages can serve as tetradentate N 2 S 2 ligands, utilizing carboxamido nitrogen and cysteinyl sulfur atoms as donors in metalloenzyme active sites, has recently been verified in several protein crystal structures. [1][2][3][4][5] It was further discovered that the nickel-bound Cys-Gly-Cys NiN 2 S 2 moiety of acetyl coA synthase binds through bidentate bridging thiolate groups to a second nickel center which mediates the organometallic reactions required of the biocatalyst (the assembly of CH 3 + , CO, and SR À into the acetyl coA thioester CH 3 C( = O)SR). [1,2] The (Cys-GlyCys)Ni unit joins a host of synthetic NiN 2 S 2 complexes that are known to form multimetal clusters through m-SR interactions. Natures control of binuclearity in the construction of an organometallic catalyst presents the intriguing possibility that the NiN 2 S 2 complexes might be suitable for development as a novel class of ligands for organometalllic chemistry and catalysis. To this end we have characterized a series of NiN 2 S 2 complexes, four of which are shown in Figure 1, according to their electron-donating ability and stereochemical fea- Figure 1. NiN 2 S 2 complexes used as S-donor ligands; bme-daco = 1,5-(1,5-diazacyclooctane)di(ethylthiolate), bme*-daco = di(2-methyl-2-propylthiolate, bme-Me 2 pda = N,N'-dimethyl-2,9-diazanonanedithiolate, ema 4À = 2,7-dioxo-3,6-diazaoctanedithiolate.

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“…5) [39,40], but comparable with redox potentials of nickel complexes of N-substituted cyclam derivatives [41 -43].…”

Section: Electrochemical Properties Of the Complexesmentioning

confidence: 94%

Nickel(II) and Iron(II) Complexes with Tetradentate NHC/Amide Hybrid Ligands

Klawitter

Meyer

Demeshko

et al. 2013

Zeitschrift Für Naturforschung B

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Low-potential nickel(III,II) complexes: new systems based on tetradentate amidate-thiolate ligands and the influence of ligand structure on potentials in relation to the nickel site in [NiFe]-hydrogenases

Cited by 259 publications

References 6 publications

Molecular and Electronic Structures of One‐Electron Oxidized Ni^II–(Dithiosalicylidenediamine) Complexes: Ni^III–Thiolate versus Ni^II–Thiyl Radical States

Molecular and Electronic Structures of One‐Electron Oxidized Ni^II–(Dithiosalicylidenediamine) Complexes: Ni^III–Thiolate versus Ni^II–Thiyl Radical States

N₂S₂Ni Metallothiolates as a Class of Ligands that Support Organometallic and Bioorganometallic Reactivity

Nickel(II) and Iron(II) Complexes with Tetradentate NHC/Amide Hybrid Ligands

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Low-potential nickel(III,II) complexes: new systems based on tetradentate amidate-thiolate ligands and the influence of ligand structure on potentials in relation to the nickel site in [NiFe]-hydrogenases

Cited by 259 publications

References 6 publications

Molecular and Electronic Structures of One‐Electron Oxidized NiII–(Dithiosalicylidenediamine) Complexes: NiIII–Thiolate versus NiII–Thiyl Radical States

Molecular and Electronic Structures of One‐Electron Oxidized NiII–(Dithiosalicylidenediamine) Complexes: NiIII–Thiolate versus NiII–Thiyl Radical States

N2S2Ni Metallothiolates as a Class of Ligands that Support Organometallic and Bioorganometallic Reactivity

Nickel(II) and Iron(II) Complexes with Tetradentate NHC/Amide Hybrid Ligands

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Molecular and Electronic Structures of One‐Electron Oxidized Ni^II–(Dithiosalicylidenediamine) Complexes: Ni^III–Thiolate versus Ni^II–Thiyl Radical States

Molecular and Electronic Structures of One‐Electron Oxidized Ni^II–(Dithiosalicylidenediamine) Complexes: Ni^III–Thiolate versus Ni^II–Thiyl Radical States

N₂S₂Ni Metallothiolates as a Class of Ligands that Support Organometallic and Bioorganometallic Reactivity