Density functional theory investigations of NiN2S2 reactivity as a function of nitrogen donor type and N–H···S hydrogen bonding inspired by nickel-containing superoxide dismutase

Mullins, Christopher S.; Grapperhaus, Craig A.; Kozłowski, Pawel M.

doi:10.1007/s00775-006-0109-6

Cited by 43 publications

(115 citation statements)

References 48 publications

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“…46–54 We did not observe any reaction between complex 5 and excess O 2 in CH 2 Cl 2 , even after prolonged stirring for several days. Solutions of the mono-reduced nickel(II) complex [Ni(LN 3 S)] 0 generated from Na/Hg amalgam in THF were next tested for their reactivity toward O 2 .…”

Section: Resultsmentioning

confidence: 68%

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Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N₄S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

et al. 2013

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The known iron(II) complex [FeII(LN3S)(OTf)] (1) was used as starting material to prepare the new biomimetic (N4S(thiolate)) iron(II) complexes [FeII(LN3S)(py)](OTf) (2) and [FeII(LN3S)(DMAP)](OTf) (3), where LN3S is a tetradentate bis(imino)pyridine (BIP) derivative with a covalently tethered phenylthiolate donor. These complexes were characterized by X-ray crystallography, UV-vis, 1H NMR, and Mössbauer spectroscopy, as well as electrochemistry. A nickel(II) analogue, [NiII(LN3S)](BF4) (5), was also synthesized and characterized by structural and spectroscopic methods. Cyclic voltammetric studies showed 1 – 3 and 5 undergo a single reduction process with E1/2 between −0.9 to −1.2 V versus Fc+/Fc. Treatment of 3 with 0.5% Na/Hg amalgam gave the mono-reduced complex [Fe(LN3S)(DMAP)]0 (4), which was characterized by X-ray crystallography, UV-vis, EPR (g = [2.155, 2.057, 2.038]) and Mössbauer (δ = 0.33 mm s−1; ΔEQ = 2.04 mm s−1) spectroscopies. Computational methods (DFT) were employed to model complexes 3 – 5. The combined experimental and computational studies show that 1 – 3 are 5-coordinate, high-spin (S = 2) FeII complexes, whereas 4 is best described as a 5-coordinate, intermediate-spin (S = 1) FeII complex antiferromagnetically coupled to a ligand radical. This unique electronic configuration leads to an overall doublet spin (Stotal = ½) ground state. Complexes 2 and 3 are shown to react with O2 to give S-oxygenated products, as previously reported for 1. In contrast, the mono-reduced 4 appears to react with O2 to give a mixture of S- and Fe-oxygenates. The nickel(II) complex 5 does not react with O2, and even when the mono-reduced nickel complex is produced, it appears to undergo only outer-sphere oxidation with O2.

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Section: Resultsmentioning

confidence: 68%

“…This lack of reactivity is in contrast to the iron analogs, as well as some nickel-thiolate complexes that do react with O 2 to give S-oxygenated sulfinato and sulfonato products, although these reactions can be sluggish. 46–54 …”

Section: Introductionmentioning

confidence: 99%

Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N₄S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

et al. 2013

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“…In addition, our calculations indicate that the coordination geometry of the metal center and conformation of the ligand backbones play a major role in determining the composition of the redox-active orbitals. [60] This is most apparent for the calculations of 1(py) 2 + and 2(py) 2 + ; the latter complex, for which C 2v symmetry was imposed, possesses a SOMO that has no S p-character. Thus, it www.chemeurj.org is likely that the conformation of the protein side chains is also important in fine-tuning the nature of the electronic structure of the active site of NiSOD.…”

Section: A C H T U N G T R E N N U N G (Emb)]mentioning

confidence: 93%

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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“…[18][19][20] A multitude of possible intermediates and mechanisms, which are further complicated by the possibility of various proton sources as well as a variable spin (high or low) on nickel are theoretically possible. For example, one current study suggests that as O 2 C À approaches the active site, it is protonated before it reaches the central nickel ion.…”

Section: Introductionmentioning

confidence: 99%

Solution Structure of a Functional Biomimetic and Mechanistic Implications for Nickel Superoxide Dismutases

et al. 2008

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The nickel complex of a synthetic nonapeptide (HCDLPCFVY-NH2) is capable of catalytically disproportionating O2(.-) and is thus a functional biomimetic for nickel superoxide dismutases. This represents a simplification as compared to a NiSOD "maquette" that is based on a dodecapeptide that was recently reported [Inorg. Chem. 2006, 45, 2358]. The 3D solution structure reveals that the first six residues form a stable macrocyclic structure with a preformed binding site for Ni(II). Proline 5 exhibits a trans peptide linkage in the biomimetic and a cis conformation in NiSOD enzymes. DFT calculations reveal the source of this preference. Mechanistic consequences for the mode of action (identity of the fifth ligand) are discussed. The SOD activity is compared to enzymatic systems, and selected modifications allowed the biomimetic to be reduced to a functional minimal motif of only six amino acids (ACAAPC-NH2).

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Density functional theory investigations of NiN2S2 reactivity as a function of nitrogen donor type and N–H···S hydrogen bonding inspired by nickel-containing superoxide dismutase

Cited by 43 publications

References 48 publications

Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N₄S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N₄S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

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

Solution Structure of a Functional Biomimetic and Mechanistic Implications for Nickel Superoxide Dismutases

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Density functional theory investigations of NiN2S2 reactivity as a function of nitrogen donor type and N–H···S hydrogen bonding inspired by nickel-containing superoxide dismutase

Cited by 43 publications

References 48 publications

Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N4S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N4S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

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

Solution Structure of a Functional Biomimetic and Mechanistic Implications for Nickel Superoxide Dismutases

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Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N₄S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N₄S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

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