Resolving Conformation Dichotomy for Y‐ and T‐Shaped Three‐Coordinate Ni<sup>I</sup> Carbonyl Complexes with Relativistic DFT Analysis of EPR Fingerprints

Pietrzyk, Piotr; Podolska, Katarzyna; Sojka, Zbigniew

doi:10.1002/chem.200901805

Cited by 14 publications

(11 citation statements)

References 32 publications

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“…6,21,24 As shown earlier, the g tensor is sensitive to the conformation type and the resulting ground state, 24 which allows for a clear-cut assignment of the observed {Ni I -CO} adduct in ZSM-5 to the T conformation with the predominant 3d xz SOMO, consistent with the observed sequence g zz > g yy >> g xx of the g values (Table 1). As already mentioned, it can assume one of the generic T or Y conformations know from the bioinorganic complexes, where the nickel(I) core remains threecoordinated.…”

Section: Binding Of Co To Ni(i) Sitessupporting

confidence: 78%

“…6,21,24 It has also been found that the Y or T conformations involve a significant difference in the electronic structure and reactivity of the three-coordinate complexes in ligand substitution and transmetalation reactions, constituting an essential factor in the structural and kinetic studies. 6,21,24 It has also been found that the Y or T conformations involve a significant difference in the electronic structure and reactivity of the three-coordinate complexes in ligand substitution and transmetalation reactions, constituting an essential factor in the structural and kinetic studies.…”

Section: Introductionmentioning

confidence: 99%

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Intimate Binding Mechanism and Structure of Trigonal Nickel(I) Monocarbonyl Adducts in ZSM-5 Zeolite—Spectroscopic Continuous Wave EPR, HYSCORE, and IR Studies Refined with DFT Quantification of Disentangled Electron and Spin Density Redistributions along σ and π Channels

et al. 2013

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Interaction of tetracoordinated nickel(I) centers generated inside the channels of ZSM-5 zeolite with carbon monoxide ((12,13)CO, pCO < 1 Torr) led to the formation of T-shaped, top-on monocarbonyl adducts with a unique trigonal nickel core, supported by two oxygen donor ligands. The mechanism of the formation of the {Ni(I)-CO}ZSM-5 species was accounted for by a quantitative molecular orbital correlation diagram of CO ligation. Detailed electronic and magnetic structure of this adduct was obtained from comprehensive DFT calculations, validated by quantitative reproduction of its continuous wave electron paramagnetic resonance (CW-EPR), hyperfine sublevel correlation (HYSCORE), and IR fingerprints, using relativistic Pauli and ZORA-SOMF/B3LYP methods. Molecular analysis of the stretching frequency, νCO = 2109 cm(-1), g and A((13)C) tensors (g(xx) = 2.018, g(yy) = 2.380, g(zz) = 2.436, A(xx) = +1.0 ± 0.3 MHz, A(yy) = -3.6 ± 0.9 MHz, A(zz) = -1.6 ± 0.3 MHz) and Q((27)Al) parameters (e(2)Qq/h = -13 MHz and η = 0.8) supported by quantum chemical modeling revealed that the Ni-CO bond results from the π overlap between the low-laying π(2p) CO states with the 3d(xz) and 3d(yz) orbitals, with a small σ contribution due to the overlap of σ(2p+2s) orbital and a protruding lobe of the in-plane 3d(xz) orbital. Two types of orbital channels (associated with the σ and π overlap) of the electron and spin density flows within the {Ni(I)-CO} unit were identified. A bathochromic shift of the νCO stretching vibration was accounted for by resolving quantitatively the separate contributions due to the σ donation and π back-donation, whereas the (13)C hyperfine coupling was rationalized by incongruent α and β spin flows via the σ and π channels. As a result the very nature of the carbon-metal bond in the Ni(I)-CO adduct and the molecular backbone of the corresponding spectroscopic parameters were revealed with unprecedented accuracy.

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Section: Binding Of Co To Ni(i) Sitessupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Intimate Binding Mechanism and Structure of Trigonal Nickel(I) Monocarbonyl Adducts in ZSM-5 Zeolite—Spectroscopic Continuous Wave EPR, HYSCORE, and IR Studies Refined with DFT Quantification of Disentangled Electron and Spin Density Redistributions along σ and π Channels

et al. 2013

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“…This ESR feature is characteristic to the model complex containing a T-shaped Ni I −monocarbonyl adduct (Figure 1b). 38,39 Thus, the ESR signature of the NiMFI-Red sample indicates the presence of the T-shaped Ni I −monocarbonyl species (Figure 1b).…”

Section: Resultsmentioning

confidence: 96%

Experimental Description of Biomimetic Ni^II–Superoxo δ-Bond: Franck–Condon Analyses on Its Vibronically-Resolved Spectrum

et al. 2020

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Mononuclear metal−dioxygen species (M−O 2 ) are key intermediates in a variety of the oxidative transformation processes mediated by heme and nonheme metalloenzymes. Understanding their O 2 -activation mechanism at an orbital level is still of scientific significance. In the present work, we spectroscopically analyzed the biomimetic Ni II −superoxo δ-bond: the origin of its abnormal electrophilic reactivity. We prepared the biomimetic Ni II −superoxo species through the room temperature reaction of the Ni I site with O 2 in MFI zeolite. Under vacuum condition, this isolated species acts like a metal oxide molecule in the gas phase, and it gives the vibronically resolved spectrum that is generally seen in the vapor phase. This type of spectroscopic probe has never been observed for past M−O 2 complexes. Through a combination of an isotopic experiment and quantum chemical calculations, we successfully assigned the observed vibrational fine structure as the vibronic progression in a stretching O−O vibrational structure associated with the excitation from doubly occupied δ orbital to singly occupied δ* orbital (SOMO). This spectroscopic probe provides information on how the δ channel interaction contributes to the activation of O−O bond in an O 2 molecule. The recondite vibronic progression feature was well reproduced by DFT cluster calculation assuming the square planar Ni II −superoxo site, by which we successfully obtained the spectroscopically calibrated DFT cluster model that well describes Ni II −superoxo δ-bond. This model revealed that Ni II −superoxo δ-bond is ionic rather than covalent. The high ionicity of the δ bond results in the high oxygen character in the important frontier molecular orbital (FMO) for the electrophilic oxidative reaction, i.e., the unoccupied β-spin O 2 -π* orbital. This is why that Ni ion stabilizes superoxo ligand having abnormal electrophilic reactivity. The findings in the present study provide general description of the Ni−superoxo δbond and maybe can help us to uncover the structure−reactivity relationships of the metalloprotein.

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“…It is thus tempting to regard [ show only slight distortion from a trigonal planar coordination, as exemplified by the nickel(III) imide (Figure 1B) by the group of Warren. [30] As a T-shaped geometry of three-coordinate complexes is not unusual for electron rich d-metals [39][40][41][42][43] this speaks to steric constraints in those complexes. The geometry of [1] À resembles thus more the T-shaped nickel(III) methyl complex [Ni(Me)L 2 ], where the methyl group adopts the equatorial position.…”

Section: Resultsmentioning

confidence: 99%

On the Synthesis of a T‐Shaped Imido Nickel Complex and Trigonal Amido Nickel Complexes

2022

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The synthesis of a T‐shaped imido nickel complex is reported, obtained by the reaction of phenyl azide with the linear nickel(I) silylamide complex K{18‐crown‐6}[NiL2] (L=−N(Dipp)SiMe3; Dipp=2,6‐diisopropylphenyl). In addition, an unusual shift of a SiMe3 unit from an ancillary ligand to a putative [Ni=NPh] complex is observed. Examination of the resulting [Ni=NDipp] complex for its electronic properties leads to its description as a low‐spin nickel(III) imide and revealed only limited activity with respect to H‐atom abstraction from C−H bonds or nitrene. Attempts to obtain information about the general features of trigonal nickel(II) amide products, that would result from such a H‐atom abstraction reaction, via reaction of linear nickel(II) silylamide [NiL2] with alkali metal salts of primary amides revealed the reduction to the linear nickel(I) complex K{18‐crown‐6}[NiL2]. The same is observed for alkoxides, secondary amides or benzyl. Reaction of the organic salts with the anionic nickel(II) complex NBu4[NiBrL2] under salt elimination also give the linear nickel(I) complex. Partial formation of an otherwise stable T‐shaped nickel(II) can be observed only for the electron‐poor diphenyl amide. This implicates that reduction of the starting nickel(II) complexes by different organic alkali metal salts likely does not occur via a homolytic Ni−R bond cleavage but a direct SET process from the unligated substrate to the nickel(II) ion.

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Resolving Conformation Dichotomy for Y‐ and T‐Shaped Three‐Coordinate Ni^I Carbonyl Complexes with Relativistic DFT Analysis of EPR Fingerprints

Cited by 14 publications

References 32 publications

Intimate Binding Mechanism and Structure of Trigonal Nickel(I) Monocarbonyl Adducts in ZSM-5 Zeolite—Spectroscopic Continuous Wave EPR, HYSCORE, and IR Studies Refined with DFT Quantification of Disentangled Electron and Spin Density Redistributions along σ and π Channels

Intimate Binding Mechanism and Structure of Trigonal Nickel(I) Monocarbonyl Adducts in ZSM-5 Zeolite—Spectroscopic Continuous Wave EPR, HYSCORE, and IR Studies Refined with DFT Quantification of Disentangled Electron and Spin Density Redistributions along σ and π Channels

Experimental Description of Biomimetic Ni^II–Superoxo δ-Bond: Franck–Condon Analyses on Its Vibronically-Resolved Spectrum

On the Synthesis of a T‐Shaped Imido Nickel Complex and Trigonal Amido Nickel Complexes

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Resolving Conformation Dichotomy for Y‐ and T‐Shaped Three‐Coordinate NiI Carbonyl Complexes with Relativistic DFT Analysis of EPR Fingerprints

Cited by 14 publications

References 32 publications

Intimate Binding Mechanism and Structure of Trigonal Nickel(I) Monocarbonyl Adducts in ZSM-5 Zeolite—Spectroscopic Continuous Wave EPR, HYSCORE, and IR Studies Refined with DFT Quantification of Disentangled Electron and Spin Density Redistributions along σ and π Channels

Intimate Binding Mechanism and Structure of Trigonal Nickel(I) Monocarbonyl Adducts in ZSM-5 Zeolite—Spectroscopic Continuous Wave EPR, HYSCORE, and IR Studies Refined with DFT Quantification of Disentangled Electron and Spin Density Redistributions along σ and π Channels

Experimental Description of Biomimetic NiII–Superoxo δ-Bond: Franck–Condon Analyses on Its Vibronically-Resolved Spectrum

On the Synthesis of a T‐Shaped Imido Nickel Complex and Trigonal Amido Nickel Complexes

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Resolving Conformation Dichotomy for Y‐ and T‐Shaped Three‐Coordinate Ni^I Carbonyl Complexes with Relativistic DFT Analysis of EPR Fingerprints

Experimental Description of Biomimetic Ni^II–Superoxo δ-Bond: Franck–Condon Analyses on Its Vibronically-Resolved Spectrum