1
|
Emerson-King J, Gransbury GK, Whitehead GFS, Vitorica-Yrezabal IJ, Rouzières M, Clérac R, Chilton NF, Mills DP. Isolation of a Bent Dysprosium Bis(amide) Single-Molecule Magnet. J Am Chem Soc 2024; 146:3331-3342. [PMID: 38282511 PMCID: PMC10859956 DOI: 10.1021/jacs.3c12427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 01/30/2024]
Abstract
The isolation of formally two-coordinate lanthanide (Ln) complexes is synthetically challenging, due to predominantly ionic Ln bonding regimes favoring high coordination numbers. In 2015, it was predicted that a near-linear dysprosium bis(amide) cation [Dy{N(SiiPr3)2}2]+ could provide a single-molecule magnet (SMM) with an energy barrier to magnetic reversal (Ueff) of up to 2600 K, a 3-fold increase of the record Ueff for a Dy SMM at the time; this work showed a potential route to SMMs that can provide high-density data storage at higher temperatures. However, synthetic routes to a Dy complex containing only two monodentate ligands have not previously been realized. Here, we report the synthesis of the target bent dysprosium bis(amide) complex, [Dy{N(SiiPr3)2}2][Al{OC(CF3)3}4] (1-Dy), together with the diamagnetic yttrium analogue. We find Ueff = 950 ± 30 K for 1-Dy, which is much lower than the predicted values for idealized linear two-coordinate Dy(III) cations. Ab initio calculations of the static electronic structure disagree with the experimentally determined height of the Ueff barrier, thus magnetic relaxation is faster than expected based on magnetic anisotropy alone. We propose that this is due to enhanced spin-phonon coupling arising from the flexibility of the Dy coordination sphere, in accord with ligand vibrations being of equal importance to magnetic anisotropy in the design of high-temperature SMMs.
Collapse
Affiliation(s)
- Jack Emerson-King
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Gemma K. Gransbury
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - George F. S. Whitehead
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | | | | | | | - Nicholas F. Chilton
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Research
School of Chemistry, The Australian National
University, Sullivans
Creek Road, Canberra, ACT 2601, Australia
| | - David P. Mills
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| |
Collapse
|
2
|
Jin PB, Luo QC, Gransbury GK, Vitorica-Yrezabal IJ, Hajdu T, Strashnov I, McInnes EJL, Winpenny REP, Chilton NF, Mills DP, Zheng YZ. Thermally Stable Terbium(II) and Dysprosium(II) Bis-amidinate Complexes. J Am Chem Soc 2023; 145:27993-28009. [PMID: 37997752 PMCID: PMC10755703 DOI: 10.1021/jacs.3c07978] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/25/2023]
Abstract
The thermostable four-coordinate divalent lanthanide (Ln) bis-amidinate complexes [Ln(Piso)2] (Ln = Tb, Dy; Piso = {(NDipp)2CtBu}, Dipp = C6H3iPr2-2,6) were prepared by the reduction of parent five-coordinate Ln(III) precursors [Ln(Piso)2I] (Ln = Tb, Dy) with KC8; halide abstraction of [Ln(Piso)2I] with [H(SiEt3)2][B(C6F5)] gave the respective Ln(III) complexes [Ln(Piso)2][B(C6F5)]. All complexes were characterized by X-ray diffraction, ICP-MS, elemental analysis, SQUID magnetometry, UV-vis-NIR, ATR-IR, NMR, and EPR spectroscopy and ab initio CASSCF-SO calculations. These data consistently show that [Ln(Piso)2] formally exhibit Ln(II) centers with 4fn5dz21 (Ln = Tb, n = 8; Dy, n = 9) valence electron configurations. We show that simple assignments of the f-d coupling to either L-S or J-s schemes are an oversimplification, especially in the presence of significant crystal field splitting. The coordination geometry of [Ln(Piso)2] is intermediate between square planar and tetrahedral. Projecting from the quaternary carbon atoms of the CN2 ligand backbones shows near-linear C···Ln···C arrangements. This results in strong axial ligand fields to give effective energy barriers to magnetic reversal of 1920(91) K for the Tb(II) analogue and 1964(48) K for Dy(II), the highest values observed for mononuclear Ln(II) single-molecule magnets, eclipsing 1738 K for [Tb(C5iPr5)2]. We tentatively attribute the fast zero-field magnetic relaxation for these complexes at low temperatures to transverse fields, resulting in considerable mixing of mJ states.
Collapse
Affiliation(s)
- Peng-Bo Jin
- Frontier
Institute of Science and Technology (FIST), State Key Laboratory of
Electrical Insulation and Power Equipment, MOE Key Laboratory for
Nonequilibrium Synthesis of Condensed Matter, Xi’an Key Laboratory
of Electronic Devices and Materials Chemistry and School of Chemistry, Xi’an Jiaotong University, 99 Yanxiang Road, Xi’an, Shaanxi 710054, P. R. China
| | - Qian-Cheng Luo
- Frontier
Institute of Science and Technology (FIST), State Key Laboratory of
Electrical Insulation and Power Equipment, MOE Key Laboratory for
Nonequilibrium Synthesis of Condensed Matter, Xi’an Key Laboratory
of Electronic Devices and Materials Chemistry and School of Chemistry, Xi’an Jiaotong University, 99 Yanxiang Road, Xi’an, Shaanxi 710054, P. R. China
| | - Gemma K. Gransbury
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | | | - Tomáš Hajdu
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Photon
Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Ilya Strashnov
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Eric J. L. McInnes
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Photon
Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Richard E. P. Winpenny
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Nicholas F. Chilton
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - David P. Mills
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Yan-Zhen Zheng
- Frontier
Institute of Science and Technology (FIST), State Key Laboratory of
Electrical Insulation and Power Equipment, MOE Key Laboratory for
Nonequilibrium Synthesis of Condensed Matter, Xi’an Key Laboratory
of Electronic Devices and Materials Chemistry and School of Chemistry, Xi’an Jiaotong University, 99 Yanxiang Road, Xi’an, Shaanxi 710054, P. R. China
| |
Collapse
|
3
|
N-(4-Methyl-3-((4-(pyridin-3-yl)pyrimidin-2-yl)amino)phenyl)-4-((4-methylpiperazin-1-yl)methyl)benzamide. MOLBANK 2022. [DOI: 10.3390/m1461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Imatinib is one of the most used therapeutic agents to treat leukemia, which specifically inhibits the activity of tyrosine kinases. This polytopic molecule has been structurally characterized only in the form of its piperazin-1-ium salt (mesylate, picrate, citrate, fumarate or malonate). Herein we present the crystal structure of the freebase Imatinib which precipitated from a 1:10 mixture with arginine. The molecule realizes an extended conformation and forms infinite H-bonded chains through its amide, amine and pyrimidine groups.
Collapse
|