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Hu Z, Yang S. Endohedral metallofullerene molecular nanomagnets. Chem Soc Rev 2024; 53:2863-2897. [PMID: 38324027 DOI: 10.1039/d3cs00991b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Magnetic lanthanide (Ln) metal complexes exhibiting magnetic bistability can behave as molecular nanomagnets, also known as single-molecule magnets (SMMs), suitable for storing magnetic information at the molecular level, thus attracting extensive interest in the quest for high-density information storage and quantum information technologies. Upon encapsulating Ln ion(s) into fullerene cages, endohedral metallofullerenes (EMFs) have been proven as a promising and versatile platform to realize chemically robust SMMs, in which the magnetic properties are able to be readily tailored by altering the configurations of the encapsulated species and the host cages. In this review, we present critical discussions on the molecular structures and magnetic characterizations of EMF-SMMs, with the focus on their peculiar molecular and electronic structures and on the intriguing molecular magnetism arising from such structural uniqueness. In this context, different families of magnetic EMFs are summarized, including mononuclear EMF-SMMs wherein single-ion anisotropy is decisive, dinuclear clusterfullerenes whose magnetism is governed by intramolecular magnetic interaction, and radical-bridged dimetallic EMFs with high-spin ground states that arise from the strong ferromagnetic coupling. We then discuss how molecular assemblies of SMMs can be constructed, in a way that the original SMM behavior is either retained or altered in a controlled manner, thanks to the chemical robustness of EMFs. Finally, on the basis of understanding the structure-magnetic property correlation, we propose design strategies for high-performance EMF-SMMs by engineering ligand fields, electronic structures, magnetic interactions, and molecular vibrations that can couple to the spin states.
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Affiliation(s)
- Ziqi Hu
- Key Laboratory of Precision and Intelligent Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Materials Science and Engineering, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei 230026, China.
| | - Shangfeng Yang
- Key Laboratory of Precision and Intelligent Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Materials Science and Engineering, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei 230026, China.
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2
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Feng Y, Hu Y, Luo T, Yuan C, Zhu W, Gao M, Huo X. Regulating the electronic and spin structure of endohedral metallofullerenes: a case investigation of Sc 3N@C 80 and Sc 3C 2@C 80. Dalton Trans 2022; 51:18734-18740. [PMID: 36453113 DOI: 10.1039/d2dt02816f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The electrochemical and paramagnetic properties of endohedral metallofullerenes (EMFs) have drawn extensive attention due to their huge potential in the fields of molecular devices, biomedicines, quantum information processing, etc. Exohedral modification of the fullerene carbon cage, such as in the classical Prato reaction, is an effective and facile approach to regulate the electronic structure and molecular dynamics of EMFs. In this work, novel pyrrolidine products of Sc3N@C80 and Sc3C2@C80 were successfully synthesized via Prato reactions using L-cysteine and paraformaldehyde. Structure characterizations demonstrated that two regioisomers with a [5,6] and a [6,6] cycloaddition on the Ih-C80 cage were obtained both for Sc3N@C80 and Sc3C2@C80. Besides, the [6,6]-monoadduct of Sc3N@C80 was thermally stable while the [5,6]-monoadduct exhibited a retro-cycloaddition ability to recover the pristine Sc3N@C80. Electrochemical measurements revealed that the redox potential of Sc3N@C80 could be tuned via such exohedral modifications. Furthermore, the paramagnetic property and internal dynamics of the encapsulated Sc3C2 cluster of Sc3C2@C80 can be well-regulated by controlling the spin density of the molecule. The present work could provide a new approach to regulate the electronic and/or spin structure of EMFs.
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Affiliation(s)
- Yongqiang Feng
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, 710021, China.
| | - Yuzhu Hu
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, 710021, China.
| | - Tianmi Luo
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, 710021, China.
| | - Chengke Yuan
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, 710021, China.
| | - Wenjie Zhu
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, 710021, China.
| | - Mengting Gao
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, 710021, China.
| | - Xuemeng Huo
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, 710021, China.
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3
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Ying X, Zhu Z, Zhao C, Zhang YQ, Tang J. Five-Coordinated Dysprosium Single-Molecule Magnet Functionalized by the SMe Group. Inorg Chem 2022; 61:20547-20551. [DOI: 10.1021/acs.inorgchem.2c03375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Xu Ying
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
| | - Zhenhua Zhu
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Chen Zhao
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
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4
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Koutsouflakis E, Krylov D, Bachellier N, Sostina D, Dubrovin V, Liu F, Spree L, Velkos G, Schimmel S, Wang Y, Büchner B, Westerström R, Bulbucan C, Kirkpatrick K, Muntwiler M, Dreiser J, Greber T, Avdoshenko SM, Dorn H, Popov AA. Metamagnetic transition and a loss of magnetic hysteresis caused by electron trapping in monolayers of single-molecule magnet Tb 2@C 79N. NANOSCALE 2022; 14:9877-9892. [PMID: 35781298 DOI: 10.1039/d1nr08475e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Realization of stable spin states in surface-supported magnetic molecules is crucial for their applications in molecular spintronics, memory storage or quantum information processing. In this work, we studied the surface magnetism of dimetallo-azafullerene Tb2@C79N, showing a broad magnetic hysteresis in a bulk form. Surprisingly, monolayers of Tb2@C79N exhibited a completely different behavior, with the prevalence of a ground state with antiferromagnetic coupling at low magnetic field and a metamagnetic transition in the magnetic field of 2.5-4 T. Monolayers of Tb2@C79N were deposited onto Cu(111) and Au(111) by evaporation in ultra-high vacuum conditions, and their topography and electronic structure were characterized by scanning tunneling microscopy and spectroscopy (STM/STS). X-ray photoelectron spectroscopy (XPS), in combination with DFT studies, revealed that the nitrogen atom of the azafullerene cage tends to avoid metallic surfaces. Magnetic properties of the (sub)monolayers were then studied by X-ray magnetic circular dichroism (XMCD) at the Tb-M4,5 absorption edge. While in bulk powder samples Tb2@C79N behaves as a single-molecule magnet with ferromagnetically coupled magnetic moments and blocking of magnetization at 28 K, its monolayers exhibited a different ground state with antiferromagnetic coupling of Tb magnetic moments. To understand if this unexpected behavior is caused by a strong hybridization of fullerenes with metallic substrates, XMCD measurements were also performed for Tb2@C79N adsorbed on h-BN|Rh(111) and MgO|Ag(100). The co-existence of two forms of Tb2@C79N was found on these substrates as well, but magnetization curves showed narrow magnetic hysteresis detectable up to 25 K. The non-magnetic state of Tb2@C79N in monolayers is assigned to anionic Tb2@C79N- species with doubly-occupied Tb-Tb bonding orbital and antiferromagnetic coupling of the Tb moments. A charge transfer from the substrate or trapping of secondary electrons are discussed as a plausible origin of these species.
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Affiliation(s)
- Emmanouil Koutsouflakis
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Denis Krylov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Nicolas Bachellier
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Daria Sostina
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Vasilii Dubrovin
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Fupin Liu
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Lukas Spree
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Georgios Velkos
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Sebastian Schimmel
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Yaofeng Wang
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Rasmus Westerström
- The Division of Synchrotron Radiation Research, Lund University, SE-22100 Lund, Sweden
- NanoLund, Lund University, Box 118, 22100 Lund, Sweden
| | - Claudiu Bulbucan
- The Division of Synchrotron Radiation Research, Lund University, SE-22100 Lund, Sweden
- NanoLund, Lund University, Box 118, 22100 Lund, Sweden
| | - Kyle Kirkpatrick
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
| | - Matthias Muntwiler
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Jan Dreiser
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Thomas Greber
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Physik-Institut der Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Stas M Avdoshenko
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Harry Dorn
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
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5
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Dubrovin V, Avdoshenko SM. Conformational preferences of endohedral metallofullerenes on Ag, Au, and MgO surfaces: Theoretical studies. J Comput Chem 2022; 43:1614-1620. [PMID: 35778938 DOI: 10.1002/jcc.26962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/12/2022] [Accepted: 06/18/2022] [Indexed: 11/09/2022]
Abstract
In this report, we study the ordering of C60 , Sc3 N@C80 , and Dy2 ScN@C80 molecules on different metallic and dielectric surfaces such as Ag(100), Au(111), and MgO(100). By using DFT techniques, we can classify different types of cage-to-surface arrangements and their relative energies. Using a proposed homogenous sampling of the conformational space for the M3 N cluster, we determine a potential energy map that is capable of providing a structural distribution for a given energy window. We find that Coulomb interaction is a dominant force that governs the system's stability and order. However, a deep analysis of the charge density rearrangements reveals that even though the integral charges may be considered as a qualitative control parameter, it fails to provide quantitative data due to the importance of spatial characteristics of charge densities.
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Affiliation(s)
- Vasilii Dubrovin
- Leibniz Institute for Solid State and Materials Research Dresden, Dresden, Germany
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6
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Wang J, Hu S, Yang B, Jin G, Zhou X, Lin X, Wang R, Lu Y, Zhang L. Novel Three-Dimensional-Printing Strategy Based on Dynamic Urea Bonds for Isotropy and Mechanical Robustness of Large-Scale Printed Products. ACS APPLIED MATERIALS & INTERFACES 2022; 14:1994-2005. [PMID: 34963290 DOI: 10.1021/acsami.1c20659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Additive manufacturing via fused deposition modeling (FDM) has become one of the most widely used technologies owing to its ease of operation and effective cost. However, the disappointing interlayer adhesion produced by FDM often results in inferior mechanical properties, which has become a technical bottleneck for industrial production. Herein, we demonstrate a facile and efficient printing strategy to enhance interlayer adhesion by introducing a self-healing mechanism into the printing material, thereby concurrently enhancing the mechanical properties and isotropy of the printed products. This strategy relies on the self-healing property of three-dimensional-printing materials. This self-healing property is endowed by introducing dynamic urea bonds on the thermoplastic polyurethane (TPU) molecular chains, and then, such dynamic bonds can be activated through thermal heating. Accordingly, the synthesized TPU reveals an efficient self-healing property and excellent printability owing to the existence of dynamic reversible covalent bonds. Moreover, objects with complex structures can be split and printed and then assembled using this strategy, avoiding the need for supporting structures and realizing the rapid prototyping of large-sized objects. The printing strategy proposed paves a candidate way to overcome the current challenges in obtaining high-quality products via FDM.
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Affiliation(s)
- Jun Wang
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Shikai Hu
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Bin Yang
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Guangzhi Jin
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xinxin Zhou
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiang Lin
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Runguo Wang
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yonglai Lu
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Liqun Zhang
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
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7
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Kuppusamy SK, Suryadevara N, Mizuno A, Spieker L, Salamon S, Sleziona S, Maas A, Pollmann E, Heinrich B, Schleberger M, Wende H, Ruben M. Structural Insights into Hysteretic Spin-Crossover in a Set of Iron(II)-2,6-bis(1H-pyrazol-1-yl)pyridine) Complexes. Chemistry 2021; 28:e202103853. [PMID: 34939670 PMCID: PMC9305185 DOI: 10.1002/chem.202103853] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Indexed: 11/21/2022]
Abstract
Bistable spin‐crossover (SCO) complexes that undergo abrupt and hysteretic (ΔT1/2) spin‐state switching are desirable for molecule‐based switching and memory applications. In this study, we report on structural facets governing hysteretic SCO in a set of iron(II)‐2,6‐bis(1H‐pyrazol‐1‐yl)pyridine) (bpp) complexes – [Fe(bpp−COOEt)2](X)2⋅CH3NO2 (X=ClO4, 1; X=BF4, 2). Stable spin‐state switching – T1/2=288 K; ΔT1/2=62 K – is observed for 1, whereas 2 undergoes above‐room‐temperature lattice‐solvent content‐dependent SCO – T1/2=331 K; ΔT1/2=43 K. Variable‐temperature single‐crystal X‐ray diffraction studies of the complexes revealed pronounced molecular reorganizations – from the Jahn‐Teller‐distorted HS state to the less distorted LS state – and conformation switching of the ethyl group of the COOEt substituent upon SCO. Consequently, we propose that the large structural reorganizations rendered SCO hysteretic in 1 and 2. Such insights shedding light on the molecular origin of thermal hysteresis might enable the design of technologically relevant molecule‐based switching and memory elements.
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Affiliation(s)
- Senthil Kumar Kuppusamy
- Karlsruhe Institute of Technology: Karlsruher Institut fur Technologie, Institute for quantum materials and technologies, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen,, 76344, Karlsruhe, GERMANY
| | - Nithin Suryadevara
- Karlsruhe Institute of Technology: Karlsruher Institut fur Technologie, IQMT, GERMANY
| | - Asato Mizuno
- Karlsruhe Institute of Technology: Karlsruher Institut fur Technologie, INT, GERMANY
| | - Lea Spieker
- University of Duisburg-Essen: Universitat Duisburg-Essen, Faculty of Physics and CENIDE, GERMANY
| | - Soma Salamon
- University of Duisburg-Essen: Universitat Duisburg-Essen, Faculty of Physics and CENIDE, GERMANY
| | - Stephan Sleziona
- University of Duisburg-Essen: Universitat Duisburg-Essen, Faculty of Physics and CENIDE, GERMANY
| | - André Maas
- University of Duisburg-Essen: Universitat Duisburg-Essen, Faculty of Physics and CENIDE, GERMANY
| | - Erik Pollmann
- University of Duisburg-Essen: Universitat Duisburg-Essen, Faculty of Physics and CENIDE, GERMANY
| | - Benoît Heinrich
- IPCMS: Institut de physique et chimie des materiaux de Strasbourg, DMO, FRANCE
| | - Marika Schleberger
- University of Duisburg-Essen: Universitat Duisburg-Essen, Faculty of Physics and CENIDE, GERMANY
| | - Heiko Wende
- University of Duisburg-Essen: Universitat Duisburg-Essen, Faculty of Physics and CENIDE, GERMANY
| | - Mario Ruben
- Karlsruhe Institute of Technology: Karlsruher Institut fur Technologie, Institute of Nanotechnology, GERMANY
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Dey S, Rajaraman G. Attaining record-high magnetic exchange, magnetic anisotropy and blocking barriers in dilanthanofullerenes. Chem Sci 2021; 12:14207-14216. [PMID: 34760206 PMCID: PMC8565386 DOI: 10.1039/d1sc03925c] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 10/06/2021] [Indexed: 11/29/2022] Open
Abstract
While the blocking barrier (U eff) and blocking temperature (T B) for "Dysprocenium" SIMs have been increased beyond liquid N2 temperature, device fabrication of these molecules remains a challenge as low-coordinate Ln3+ complexes are very unstable. Encapsulating the lanthanide ion inside a cage such as a fullerene (called endohedral metallofullerene or EMF) opens up a new avenue leading to several Ln@EMF SMMs. The ab initio CASSCF calculations play a pivotal role in identifying target metal ions and suitable cages in this area. Encouraged by our earlier prediction on Ln2@C79N, which was verified by experiments, here we have undertaken a search to enhance the exchange coupling in this class of molecules beyond the highest reported value. Using DFT and ab initio calculations, we have studied a series of Gd2@C2n (30 ≤ 2n ≤ 80), where an antiferromagnetic J Gd⋯Gd of -43 cm-1 was found for a stable Gd2@C38-D 3h cage. This extremely large and exceptionally rare 4f⋯4f interaction results from a direct overlap of 4f orbitals due to the confinement effect. In larger cages such as Gd2@C60 and Gd2@C80, the formation of two centre-one-electron (2c-1e-) Gd-Gd bonds is perceived. This results in a radical formation in the fullerene cage leading to its instability. To avoid this, we have studied heterofullerenes where one of the carbon atoms is replaced by a nitrogen atom. Specifically, we have studied Ln2@C59N and Ln2@C79N, where strong delocalisation of the electron yields a mixed valence-like behaviour. This suggests a double-exchange (B) is operational, and CASSCF calculations yield a B value of 434.8 cm-1 and resultant J Gd-rad of 869.5 cm-1 for the Gd2@C59N complex. These parameters are found to be two times larger than the world-record J reported for Gd2@C79N. Further ab initio calculations reveal an unprecedented U cal of 1183 and 1501 cm-1 for Dy2@C59N and Tb2@C59N, respectively. Thus, this study offers strong exchange coupling as criteria for new generation SMMs as the existing idea of enhancing the blocking barrier via crystal field modulation has reached its saturation point.
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Affiliation(s)
- Sourav Dey
- Department of Chemistry, Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay Powai Mumbai 400076 India
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9
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Singha A, Sostina D, Wolf C, Ahmed SL, Krylov D, Colazzo L, Gargiani P, Agrestini S, Noh WS, Park JH, Pivetta M, Rusponi S, Brune H, Heinrich AJ, Barla A, Donati F. Mapping Orbital-Resolved Magnetism in Single Lanthanide Atoms. ACS NANO 2021; 15:16162-16171. [PMID: 34546038 DOI: 10.1021/acsnano.1c05026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Single lanthanide atoms and molecules are promising candidates for atomic data storage and quantum logic due to the long lifetime of their magnetic quantum states. Accessing and controlling these states through electrical transport requires precise knowledge of their electronic configuration at the level of individual atomic orbitals, especially of the outer shells involved in transport. However, no experimental techniques have so far shown the required sensitivity to probe single atoms with orbital selectivity. Here we resolve the magnetism of individual orbitals in Gd and Ho single atoms on MgO/Ag(100) by combining X-ray magnetic circular dichroism with multiplet calculations and density functional theory. In contrast to the usual assumption of bulk-like occupation of the different electronic shells, we establish a charge transfer mechanism leading to an unconventional singly ionized configuration. Our work identifies the role of the valence electrons in determining the quantum level structure and spin-dependent transport properties of lanthanide-based nanomagnets.
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Affiliation(s)
- Aparajita Singha
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
- Max Planck Institute for Solid State Research, Stuttgart 70569, Germany
| | - Daria Sostina
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Christoph Wolf
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Safa L Ahmed
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Denis Krylov
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Luciano Colazzo
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Pierluigi Gargiani
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290 Catalonia, Spain
| | - Stefano Agrestini
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290 Catalonia, Spain
| | - Woo-Suk Noh
- MPPC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Republic of Korea
| | - Jae-Hoon Park
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Marina Pivetta
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Station 3, CH-1015 Lausanne, Switzerland
| | - Stefano Rusponi
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Station 3, CH-1015 Lausanne, Switzerland
| | - Harald Brune
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Station 3, CH-1015 Lausanne, Switzerland
| | - Andreas J Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Alessandro Barla
- Istituto di Struttura della Materia (ISM), Consiglio Nazionale delle Ricerche (CNR), I-34149 Trieste, Italy
| | - Fabio Donati
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
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10
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Li W, Wang C, Wang T. Molecular structures and magnetic properties of endohedral metallofullerenes. Chem Commun (Camb) 2021; 57:10317-10326. [PMID: 34542549 DOI: 10.1039/d1cc04218a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Endohedral metallofullerenes have fascinating core-shell structures, with metal atoms or metal clusters encaged in fullerene cages, and they display various chemical, optical and magnetic properties derived from different types of fullerene cages and metal moieties. Fullerene cages can act as carriers to stabilize unusual cluster moieties. Many bizarre species that are hard to produce via synthetic methods survive well under the protection of a fullerene cage, making metallofullerenes ideal platforms for generating new clusters and bonds. Fullerene cages can also be carriers to hold active unpaired electrons. Some metallofullerenes possess electron spin and show intriguing magnetic properties, making them applicable for use in quantum computing, high density information storage and magnetoreception systems. The exploration of new metallofullerenes is still ongoing, while function-oriented studies are also promoted for the future application of metallofullerenes. Herein, we highlight the recent progress in the synthesis, electron spin characteristics and magnetic properties of metallofullerenes. Discussions and an outlook on the future development of metallofullerenes are also stated.
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Affiliation(s)
- Wang Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing 100190, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunru Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing 100190, China.
| | - Taishan Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing 100190, China.
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11
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Paschke F, Birk T, Enenkel V, Liu F, Romankov V, Dreiser J, Popov AA, Fonin M. Exceptionally High Blocking Temperature of 17 K in a Surface-Supported Molecular Magnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2102844. [PMID: 34396601 DOI: 10.1002/adma.202102844] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/09/2021] [Indexed: 06/13/2023]
Abstract
Single-molecule magnets (SMMs) are among the most promising building blocks for future magnetic data storage or quantum computing applications, owing to magnetic bistability and long magnetic relaxation times. The practical device integration requires realization of 2D surface assemblies of SMMs, where each magnetic unit shows magnetic relaxation being sufficiently slow at application-relevant temperatures. Using X-ray absorption spectroscopy and X-ray magnetic circular dichroism, it is shown that sub-monolayers of Dy2 @C80 (CH2 Ph) dimetallofullerenes prepared on graphene by electrospray deposition exhibit magnetic behavior fully comparable to that of the bulk. Magnetic hysteresis and relaxation time measurements show that the magnetic moment remains stable for 100 s at 17 K, marking the blocking temperature TB(100) , being not only in excellent agreement with that of the bulk sample but also representing by far the highest one detected for a surface-supported single-molecule magnet. The reported findings give a boost to the efforts to stabilize and address the spin degree of freedom in molecular magnets aiming at the realization of SMM-based spintronic units.
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Affiliation(s)
- Fabian Paschke
- Department of Physics, University of Konstanz, 78457, Konstanz, Germany
| | - Tobias Birk
- Department of Physics, University of Konstanz, 78457, Konstanz, Germany
| | - Vivien Enenkel
- Department of Physics, University of Konstanz, 78457, Konstanz, Germany
| | - Fupin Liu
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), 01069, Dresden, Germany
| | - Vladyslav Romankov
- Swiss Light Source, Paul Scherrer Institute, Villigen, 5232, Switzerland
| | - Jan Dreiser
- Swiss Light Source, Paul Scherrer Institute, Villigen, 5232, Switzerland
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), 01069, Dresden, Germany
| | - Mikhail Fonin
- Department of Physics, University of Konstanz, 78457, Konstanz, Germany
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12
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Sharma T, Singh MK, Gupta R, Khatua M, Rajaraman G. In silico design to enhance the barrier height for magnetization reversal in Dy(iii) sandwich complexes by stitching them under the umbrella of corannulene. Chem Sci 2021; 12:11506-11514. [PMID: 34667554 PMCID: PMC8447237 DOI: 10.1039/d1sc03160k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 07/17/2021] [Indexed: 11/21/2022] Open
Abstract
Lanthanide based single molecular magnets (SMMs), particularly dysprocenium based SIMs, are well known for their high energy barrier for spin reversal (U eff) and blocking temperatures (T B). Enhancing these two parameters and at the same time obtaining ambient stability is key to realising end-user applications such as compact storage or as qubits in quantum computing. In this work, by employing an array of theoretical tools (DFT, ab initio CASSCF and molecular dynamics), we have modelled six complexes [(η5-corannulene)Dy(Cp)] (1), [(η5-corannulene)Dy(C6H6)] (2), [(η6-corannulene)Dy(Cp)] (3), [(η6-corannulene)Dy(C6H6)] (4), [(exo-η5-corannulene)Dy(endo-η5-corannulene)] (5), and [(endo-η5-corannulene)Dy(endo-η5-corannulene)] (6) containing corannulene as a capping ligand to stabilise Dy(iii) half-sandwich complexes. Our calculations predict a strong axiality exerted by the Dy-C interactions in all complexes. Ab initio calculations predict a very large barrier height for all six molecules in the order 1 (919 cm-1) ≈ 3 (913 cm-1) > 2 (847 cm-1) > 4 (608 cm-1) ≈ 5 (603 cm-1) ≈ 6 (599 cm-1), suggesting larger barrier heights for Cp ring systems, followed by six-membered arene systems and then corannulene. DFT based molecular dynamics calculations were performed on complexes 3, 5 and 6. For complexes 3 and 5, the geometries that are dynamically accessible are far fewer. The range of U eff computed for molecular dynamics snapshots is high, indicating a possibility of translating the large U eff obtained into attractive blocking temperatures in these complexes, but the converse is found for 6. Furthermore, an in-depth C-H bond vibrational analysis performed on complex 3 suggests that the vibration responsible for reducing the blocking temperature in dysprocenium SIMs is absent here as the C-H bonds are stronger and corannulene steric strain prevents the C(Cp)-Dy-C(Cor) bending. As [(η6-corannulene)TM(X)]+ (TM = Ru, Zr, Os, Rh, Ir and X = C5Me5, C6Me6) are known, the predictions made here have a higher prospect of yielding stability under ambient conditions, a very large U eff value and a high blocking temperature - a life-giving combination to new generation SMMs.
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Affiliation(s)
- Tanu Sharma
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai-400076 India +91-22-2576-7187
| | - Mukesh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai-400076 India +91-22-2576-7187
| | - Radhika Gupta
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai-400076 India +91-22-2576-7187
| | - Munmun Khatua
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai-400076 India +91-22-2576-7187
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai-400076 India +91-22-2576-7187
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