Nickel

Schröder, Martin

doi:10.1016/0010-8545(86)80022-4

Cited by 16 publications

(3 citation statements)

References 328 publications

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“…Organonickel compounds, especially those found in catalytic transformation, are most often described going through the Ni II /Ni 0 redox states; [1][2] while the odd-electron Ni I /Ni III species are still uncommon but increasingly important oxidation states. [3][4][5][6][7][8][9] The Ni I /Ni III states are important in many nickelenzymes, especially when the nickel is part of a bimetallic or higher order cluster, such as NiFe-hydrogenase, CO-oxidoreductase, or the Ni III in Ni-superoxide dismutase (Scheme 1). [10][11][12] These clusters/non-innocent ligands distribute the charge buildup over several sites and in turn flattens the energy profile the redox-exchange.…”

Section: Introductionmentioning

confidence: 99%

Organobimetallic Nickel‐Iron Complexes, Valence Tautomer or Charge Localized Ferrocene Ligands Upon Oxidation

2022

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Section: Introductionmentioning

confidence: 99%

Organobimetallic Nickel‐Iron Complexes, Valence Tautomer or Charge Localized Ferrocene Ligands Upon Oxidation

2022

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“…Nickel is found most often in the oxidation states Ni II and Ni 0 ; , however, Ni I and Ni III may actually play a key role in several catalytic transformations − and in the activation of fundamentally important small molecules such as CO 2 , N 2 , H 2 , CO, and olefins. − ,− In these less common oxidation states nickel contains an unpaired electron. Ni I and Ni III complexes can be supported by several types of ligands, such as (pentamethyl)cyclopentadienyl (Cp or Cp*), and by strong donor ligands. ,− The uses of noninnocent ligands and metal clusters are both methods, also found in nature, to provide stability to nickel radicals through the distribution of the unpaired electron over several atoms. − Complexes with a formal Ni III center are frequently supported by multidentate, often pincer-type or macrocyclic, ligands with N being the primary ligating atom. − …”

Section: Introductionmentioning

confidence: 99%

(Benz-)imidazolin-2-ylidene-benzimidazolatonickel(II) Chelates: Syntheses, Structures, and Tuning of Noninnocent Chelate Ligand Behavior

et al. 2019

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The deprotonation of 1-(1H-benzimidazol-2-yl)-3-methylbenzimidazolium hexafluorophosphate (2 MeH2[PF6]) and 1-(1H-benzimidazol-2-yl)-3-isopropylbenzimidazolium hexafluorophosphate (2 iPrH2[PF6]) with potassium tert-butoxide in THF afforded the benzimidazolium-benzimidazolates 2 MeH and 2 iPrH. The “instant carbene” behavior of these conjugated mesomeric betaines was demonstrated by trapping their carbenic tautomers 2′ MeH and 2′ iPrH with elemental sulfur and selenium, which afforded the corresponding thio- and selenourea derivatives 2′ MeHE and 2′ iPrHE (E = S, Se). The treatment of 2 MeH and 2 iPrH with nickelocene furnished the nickel(II) complexes [NiCp(2′ Me)] and [NiCp(2′ iPr)], which contain an anionic C,Namido-chelating NHC ligand. The electronic structure and redox behavior of the nickel(II) chelates were investigated, as well as those of the closely related chelates [NiCp(1′ Me)] and [NiCp(1′ iPr)] derived from the corresponding imidazolium-benzimidazolates 1 MeH and 1 iPrH. According to DFT calculations, the highest occupied molecular orbital (HOMO) is located over the NiCp moiety and the π system of the chelate ligand with a large contribution from the (benz-)imidazolate moiety. Cyclic voltammetry revealed a reversible oxidation to the monocation [NiCp(L)]+ (E 1/2 = 0.315, 0.222, 0.396, 0.265 V vs ferrocene/ferrocenium for L = 1′ Me, 1′ iPr, 2′ Me, 2′ iPr, respectively) in CH2Cl2/0.1 M n-Bu4N[B(ArF)4] (B(ArF)4 – = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate), and isosbestic behavior was found in UV–vis–NIR spectroelectrochemical experiments. The different redox potentials reflect the different donor/acceptor properties of the NHC part of the chelate ligands, with 1′ iPr being the strongest and 2′ Me the weakest net electron donor. The EPR spectroscopic signature of [NiCp(2′ Me)]+ in CH2Cl2/0.1 M n-Bu4N[B(ArF)4] at 100 K is consistent with a chelate-ligand-based radical with strong spin–orbit coupling to the Ni center. In contrast, the EPR spectra of [NiCp(1′ Me)]+, [NiCp(1′ iPr)]+, and [NiCp(2′ iPr)]+ indicate that these monocations are best described as NiIII complexes, the comparatively higher contribution of the NiIII(L) vs the NiII(L•+) valence tautomer being supported by the results of open-shell DFT calculations.

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“…Brought to you by | New York University Bobst Library Technical Service Authenticated Download Date | 7/22/15 12:12 PM acid complexes of nickel(II) have been extensively studied [2] and detailed X-ray crystallographic studies have been reported for some of these complexes [3]. However, the X-ray structure of diaquabis(L-alaninato)nickel(II) dihydrate has not been reported.…”

Section: Introductionmentioning

confidence: 99%

Crystal structure of diaquabis(L-alaninato)nickel(II) dihydrate [Ni²⁺(NH₂CHCH₃COO^-)₂(H₂O)₂] · 2H₂O

Teoh¹,

Chan²,

Fun³

1987

Zeitschrift Für Kristallographie - Crystalline Materials

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The reaction of nickel(II) acetate with L-alanine and sodium bicarbonate results in the formation of diaquabis(L-alaninato)nickel(II) dihydrate. The pale blue complex crystallizes in the monoclinic space group Cc with a = 20.551(2), b = 6.502(3), c = 9.703(3) Α, β = 93.15(2)° and Ζ = 4, D m = 1.60 g cm -3 . The structure has been refined to R = 0.046 and R w = 0.045 based on 1280 reflections collected and 1226 used. The structure shows that the two L-alaninato ligands are trans with respect to each other with the two amino and two carboxyl donor atoms forming an approximate square plane. The geometry about the nickel is essentially a distorted octahedral structure owing to the coordination of two water molecules.

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Nickel

Cited by 16 publications

References 328 publications

Organobimetallic Nickel‐Iron Complexes, Valence Tautomer or Charge Localized Ferrocene Ligands Upon Oxidation

Organobimetallic Nickel‐Iron Complexes, Valence Tautomer or Charge Localized Ferrocene Ligands Upon Oxidation

(Benz-)imidazolin-2-ylidene-benzimidazolatonickel(II) Chelates: Syntheses, Structures, and Tuning of Noninnocent Chelate Ligand Behavior

Crystal structure of diaquabis(L-alaninato)nickel(II) dihydrate [Ni²⁺(NH₂CHCH₃COO^-)₂(H₂O)₂] · 2H₂O

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Nickel

Cited by 16 publications

References 328 publications

Organobimetallic Nickel‐Iron Complexes, Valence Tautomer or Charge Localized Ferrocene Ligands Upon Oxidation

Organobimetallic Nickel‐Iron Complexes, Valence Tautomer or Charge Localized Ferrocene Ligands Upon Oxidation

(Benz-)imidazolin-2-ylidene-benzimidazolatonickel(II) Chelates: Syntheses, Structures, and Tuning of Noninnocent Chelate Ligand Behavior

Crystal structure of diaquabis(L-alaninato)nickel(II) dihydrate [Ni2+(NH2CHCH3COO-)2(H2O)2] · 2H2O

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Crystal structure of diaquabis(L-alaninato)nickel(II) dihydrate [Ni²⁺(NH₂CHCH₃COO^-)₂(H₂O)₂] · 2H₂O