1
|
Knoell T, Polanco J, MacMillan SN, Bertke JA, Foroutan-Nejad C, Lancaster KM, 'Gus' Bakhoda A. Alkaline earth metal-assisted dinitrogen activation at nickel. Dalton Trans 2024; 53:4689-4697. [PMID: 38362644 PMCID: PMC10922974 DOI: 10.1039/d3dt03984f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Rare examples of trinuclear [Ni-N2-M-N2-Ni] core (M = Ca, Mg) with linear bridged dinitrogen ligands are reported in this work. The reduction of [iPr2NN]Ni(μ-Br)2Li(thf)2 (1) (iPr2NN = 2,4-bis-(2,6-diisopropylphenylimido)pentyl) with elemental Mg or Ca in THF under an atmosphere of dinitrogen yields the complex {iPr2NNNi(μ-N2)}2M (thf)4 (M = Mg, complex 2 and M = Ca, complex 3). The bridging end-on (μ-N2)2M(thf)4 moiety connects the two [iPr2NNNi]- nickelate fragments. A combination of X-ray crystallography, solution and solid-state spectroscopy have been applied to characterize complexes 2 and 3, and DFT studies have been used to help explain the bonding and electronic structure in these unique Ni-N2-Mg and Ni-N2-Ca complexes.
Collapse
Affiliation(s)
- Theresa Knoell
- Department of Chemistry Towson University, 8000 York Road, Towson, MD 21252, USA.
| | - Jocelyn Polanco
- Department of Chemistry Towson University, 8000 York Road, Towson, MD 21252, USA.
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Jeffery A Bertke
- Georgetown University, Department of Chemistry, Washington, DC 20057, USA
| | - Cina Foroutan-Nejad
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | | |
Collapse
|
2
|
Kokubo Y, Tsuzuki K, Sugiura H, Yomura S, Wasada-Tsutsui Y, Ozawa T, Yanagisawa S, Kubo M, Takeyama T, Yamaguchi T, Shimazaki Y, Kugimiya S, Masuda H, Kajita Y. Syntheses, Characterizations, Crystal Structures, and Protonation Reactions of Dinitrogen Chromium Complexes Supported with Triamidoamine Ligands. Inorg Chem 2023; 62:5320-5333. [PMID: 36972224 DOI: 10.1021/acs.inorgchem.2c01561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
A novel dinitrogen-dichromium complex, [{Cr(LBn)}2(μ-N2)] (1), has been prepared from reaction of CrCl3 with a lithiated triamidoamine ligand (Li3LBn) under dinitrogen. The X-ray crystal structure analysis of 1 revealed that it is composed of two independent dimeric Cr complexes bridged by N2 in the unit cell. The bridged N-N bond lengths (1.188(4) and 1.185(7) Å) were longer than the free dinitrogen molecule. The elongations of N-N bonds in 1 were also supported by the fact that the ν(N-N) stretching vibration at 1772 cm-1 observed in toluene is smaller than the free N2. Complex 1 was identified to be a 5-coordinated high spin Cr(IV) complex by Cr K-edge XANES measurement. The 1H NMR spectrum and temperature dependent magnetic susceptibility of 1 indicated that complex 1 is in the S = 1 ground state, in which two Cr(IV) ions and unpaired electron spins of the bridging N22- ligand are strongly antiferromagnetically coupled. Reaction of complex 1 with 2.3 equiv of Na or K gave chromium complexes with N2 between the Cr ion and the respective alkali metal ion, [{CrNa(LBn)(N2)(Et2O)}2] (2) and [{CrK(LBn)(N2)}4(Et2O)2] (3), respectively. Furthermore, the complexes 2 and 3 reacted with 15-crown-5 and 18-crown-6 to form the respective crown-ether adducts, [CrNa(LBn)(N2)(15-crown-5)] (4) and [CrK(LBn)(N2)(18-crown-6)] (5). The XANES measurements of complexes 2, 3, 4, and 5 revealed that they are high spin Cr(IV) complexes like complex 1. All complexes reacted with a reducing agent and a proton source to form NH3 and/or N2H4. The yields of these products in the presence of K+ were higher than those in the presence of Na+. The electronic structures and binding properties of 1, 2, 3, 4, and 5 were evaluated and discussed based on their DFT calculations.
Collapse
|
3
|
Tanabe Y, Nishibayashi Y. Recent advances in catalytic nitrogen fixation using transition metal–dinitrogen complexes under mild reaction conditions. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
4
|
Kokubo Y, Igarashi I, Nakao K, Hachiya W, Kugimiya S, Ozawa T, Masuda H, Kajita Y. The Steric Effect in Preparations of Vanadium(II)/(III) Dinitrogen Complexes of Triamidoamine Ligands Bearing Bulky Substituents. Molecules 2022; 27:5864. [PMID: 36144600 PMCID: PMC9500765 DOI: 10.3390/molecules27185864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
The reactions of newly designed lithiated triamidoamines Li3LR (R = iPr, Pen, and Cy2) with VCl3(THF)3 under N2 yielded dinitrogen-divanadium complexes with a μ-N2 between vanadium atoms [{V(LR)}2(μ-N2)] (R = iPr (1) and Pen (2)) for the former two, while not dinitrogen-divanadium complexes but a mononuclear vanadium complex with a vacant site, [V(LCy2)] (R = Cy2 (3)), were obtained for the third ligand. The V-NN2 and N-N distances were 1.7655(18) and 1.219(4) Å for 1 and 1.7935(14) and 1.226(3) Å for 2, respectively. The ν(14N-14N) stretching vibrations of 1 and 2, as measured using resonance Raman spectroscopy, were detected at 1436 and 1412 cm-1, respectively. Complex 3 reacted with potassium metal in the presence of 18-crown-6-ether under N2 to give a hetero-dinuclear vanadium complex with μ-N2 between vanadium and potassium, [VK(LCy2)(μ-N2)(18-crown-6)] (4). The N-N distance and ν(14N-14N) stretching for 4 were 1.152(3) Å and 1818 cm-1, respectively, suggesting that 4 is more activated than complexes 1 and 2. The complexes 1, 2, 3, and 4 reacted with HOTf and K[C10H8] to give NH3 and N2H4. The yields of NH3 and N2H4 (per V atom) were 47 and 11% for 1, 38 and 16% for 2, 77 and 7% for 3, and 80 and 5% for 4, respectively, and 3 and 4, which have a ligand LCy2, showed higher reactivity than 1 and 2.
Collapse
Affiliation(s)
- Yoshiaki Kokubo
- Faculty of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan
| | - Itsuki Igarashi
- Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Kenichi Nakao
- Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Wataru Hachiya
- Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Shinichi Kugimiya
- Faculty of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan
| | - Tomohiro Ozawa
- Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Hideki Masuda
- Faculty of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan
- Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Yuji Kajita
- Faculty of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan
| |
Collapse
|
5
|
Tanabe Y, Nishibayashi Y. Comprehensive insights into synthetic nitrogen fixation assisted by molecular catalysts under ambient or mild conditions. Chem Soc Rev 2021; 50:5201-5242. [PMID: 33651046 DOI: 10.1039/d0cs01341b] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
N2 is fixed as NH3 industrially by the Haber-Bosch process under harsh conditions, whereas biological nitrogen fixation is achieved under ambient conditions, which has prompted development of alternative methods to fix N2 catalyzed by transition metal molecular complexes. Since the early 21st century, catalytic conversion of N2 into NH3 under ambient conditions has been achieved by using molecular catalysts, and now H2O has been utilized as a proton source with turnover frequencies reaching the values found for biological nitrogen fixation. In this review, recent advances in the development of molecular catalysts for synthetic N2 fixation under ambient or mild conditions are summarized, and potential directions for future research are also discussed.
Collapse
Affiliation(s)
- Yoshiaki Tanabe
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Yoshiaki Nishibayashi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| |
Collapse
|
6
|
Ashida Y, Nishibayashi Y. Catalytic conversion of nitrogen molecule into ammonia using molybdenum complexes under ambient reaction conditions. Chem Commun (Camb) 2021; 57:1176-1189. [PMID: 33443504 DOI: 10.1039/d0cc07146c] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nitrogen fixation using homogeneous transition metal complexes under mild reaction conditions is a challenging topic in the field of chemistry. Several successful examples of the catalytic conversion of nitrogen molecule into ammonia using various transition metal complexes in the presence of reductants and proton sources have been reported so far, together with detailed investigations on the reaction mechanism. Among these, only molybdenum complexes have been shown to serve as effective catalysts under ambient reaction conditions, in stark contrast with other transition metal-catalysed reactions that proceed at low reaction temperature such as -78 °C. In this feature article, we classify the molybdenum-catalysed reactions into four types: reactions via the Schrock cycle, reactions via dinuclear reaction systems, reactions via direct cleavage of the nitrogen-nitrogen triple bond of dinitrogen, and reactions via the Chatt-type cycle. We describe these catalytic systems focusing on the catalytic activity and mechanistic investigations. We hope that the present feature article provides useful information to develop more efficient nitrogen fixation systems under mild reaction conditions.
Collapse
Affiliation(s)
- Yuya Ashida
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Yoshiaki Nishibayashi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| |
Collapse
|