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A high-spin nickel(II) borohydride complex in dehalogenation
- A high-spin nickel(II) borohydride complex in dehalogenation
- Tak, Hyeonwoo; Lee, Hyunjoo; Kang, Joongoo; Cho, Jaeheung
- DGIST Authors
- Kang, Joongoo; Cho, Jaeheung
- Issue Date
- Inorganic Chemistry Frontiers, 3(1), 157-163
- Article Type
- Reductive Dechlorination; Carbon-Dioxide; Coenzyme-M; 1,2-Dichloroethane; Methanobacterium
- A nickel(ii)-borohydride complex bearing a macrocyclic tridentate N-donor ligand, [Ni(Me3-TACN)(BH4)(CH3CN)]+ (Me3-TACN = 1,4,7-trimethyl-1,4,7-triazacyclononane), was prepared, isolated, and characterized by various physicochemical methods, including UV-vis, ESI-MS, IR and X-ray analyses. The structural and spectroscopic characterization clearly shows that the borohydride ligand is bound to the high-spin nickel(ii) center in an η2-manner. Density functional theory calculations provided geometric information of 2, showing that the η2-binding of borohydride to the nickel center is more favorable than the η3-binding mode in CH3CN. The complex is paramagnetic with an effective magnetic moment of 2.9μB consistent with a d8 high-spin system. The reactivity of the high-spin nickel(ii)-borohydride complex was examined in dehalogenation with numerous halocarbons. A kinetic isotope effect value of 1.7 was observed in the dehalogenation of CHCl3 by the nickel(ii)-borohydride complex. Kinetic studies and isotopic labeling experiments implicate that hydride ion or hydrogen atom transfer from the borohydride group is the rate determining step. The positive Hammett ρ value of 1.2, obtained in the reactions of [Ni(Me3-TACN)(BH4)(CH3CN)]+ and para-substituted benzoyl chloride, indicates that the dehalogenation by the nickel(ii)-borohydride species occurs via a nucleophilic reaction. © the Partner Organisations 2016.
- Royal Society of Chemistry
- Related Researcher
Computational Materials Theory Group
Computational Materials Science ＆ Materials Design; Nanomaterials for Energy Applications; Theoretical Condensed Matter Physics
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- Department of Emerging Materials ScienceComputational Materials Theory Group1. Journal Articles
Department of Emerging Materials ScienceBiomimetic Materials Laboratory1. Journal Articles
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