1
|
Zhang Y, Torres-Cavanillas R, Yan X, Zeng Y, Jiang M, Clemente-León M, Coronado E, Shi S. Spin crossover iron complexes with spin transition near room temperature based on nitrogen ligands containing aromatic rings: from molecular design to functional devices. Chem Soc Rev 2024; 53:8764-8789. [PMID: 39072682 DOI: 10.1039/d3cs00688c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
During last decades, significant advances have been made in iron-based spin crossover (SCO) complexes, with a particular emphasis on achieving reversible and reproducible thermal hysteresis at room temperature (RT). This pursuit represents a pivotal goal within the field of molecular magnetism, aiming to create molecular devices capable of operating in ambient conditions. Here, we summarize the recent progress of iron complexes with spin transition near RT based on nitrogen ligands containing aromatic rings from molecular design to functional devices. Specifically, we discuss the various factors, including supramolecular interactions, crystal packing, guest molecules and pressure effects, that could influence its cooperativity and the spin transition temperature. Furthermore, the most recent advances in their implementation as mechanical actuators, switching/memories, sensors, and other devices, have been introduced as well. Finally, we give a perspective on current challenges and future directions in SCO community.
Collapse
Affiliation(s)
- Yongjie Zhang
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, China.
| | - Ramón Torres-Cavanillas
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain.
| | - Xinxin Yan
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, China.
| | - Yixun Zeng
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, China.
| | - Mengyun Jiang
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, China.
| | - Miguel Clemente-León
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain.
| | - Eugenio Coronado
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain.
| | - Shengwei Shi
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, China.
- Key Laboratory of Optoelectronic Chemical Materials and Devices (Ministry of Education), Jianghan University, Wuhan, 430056, China
| |
Collapse
|
2
|
Zhang Y, Giménez-Santamarina S, Cardona-Serra S, Gao F, Coronado E, Brandbyge M. Strong Electron-Vibration Signals in Weakly Coupled Molecular Junctions: Activation of Spin-Crossover. NANO LETTERS 2024; 24:9846-9853. [PMID: 39092593 DOI: 10.1021/acs.nanolett.4c01684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Manipulating individual molecular spin states with electronic current has the potential to revolutionize quantum information devices. However, it is still unclear how a current can cause a spin transition in single-molecule devices. Here, we propose a spin-crossover (SCO) mechanism induced by electron-phonon coupling in an iron(II) phthalocyanine molecule situated on a graphene-decoupled Ir(111) substrate. We performed simulations of both elastic and inelastic electron tunneling spectroscopy (IETS), which reveal current-induced Fe-N vibrations and an underestimation of established electron-vibration signals. Going beyond standard perturbation theory, we examined molecules in various charge and spin states using the Franck-Condon framework. The increased probability of spin switching suggests that notable IETS signals indicate SCO triggered by the inelastic vibrational excitation associated with Fe-N stretching.
Collapse
Affiliation(s)
- Yachao Zhang
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Education University, Guiyang 550018, China
- Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | | | | | - Fei Gao
- Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Eugenio Coronado
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, 46980 Paterna, Spain
| | - Mads Brandbyge
- Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| |
Collapse
|
3
|
Trapali A, Muppal M, Pandey S, Boillot ML, Repain V, Dappe YJ, Dayen JF, Rivière E, Guillot R, Arrio MA, Otero E, Bellec A, Mallah T. Investigation of the spin crossover behaviour of a sublimable Fe(II)-qsal complex: from the bulk to a submonolayer on graphene/SiO 2. Dalton Trans 2024; 53:12519-12526. [PMID: 39012501 DOI: 10.1039/d4dt01417k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
We synthesized a sublimable molecular spin crossover Fe(II) complex based on the Schiff base tridentate ligand qsal-NEt2 (5-diethylamino-2-((quinolin-8-ylimino)methyl)phenol). The compound undergoes a transition in temperature with thermally induced excited spin state-trapping (TIESST) for high-temperature sweep rates, which can be suppressed by reducing the sweep rate. The X-ray absorption spectroscopy (XAS) studies on the microcrystalline powder confirm the TIESST effect. The molecules are deposited under ultra-high vacuum on a graphene/SiO2 substrate as a submonolayer. Investigation of the submonolayer by XAS reveals the molecular integrity and shows a spin crossover for the whole temperature range from 350 to 4 K, with residual HS species at low temperature and no TIESST effect. DFT calculations suggest a distribution of energetically similar adsorption configurations on graphene, i.e., with smooth crossover behaviour and the absence of TIESST, consistent with very weak intermolecular interactions and the absence of large molecular islands within the submonolayer.
Collapse
Affiliation(s)
- Adelais Trapali
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay 12 Cedex, France.
| | - Mukil Muppal
- Université Paris Cit é, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013, Paris, France
| | - Satakshi Pandey
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, 23 rue du Loess, Strasbourg, 67034, France
| | - Marie-Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay 12 Cedex, France.
| | - Vincent Repain
- Université Paris Cit é, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013, Paris, France
| | - Yannick J Dappe
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, Cedex, France
| | - Jean-François Dayen
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, 23 rue du Loess, Strasbourg, 67034, France
| | - Eric Rivière
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay 12 Cedex, France.
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay 12 Cedex, France.
| | - Marie-Anne Arrio
- Institutde Mineŕalogie, dePhysiquedes Mateŕiauxetde Cosmochimie, CNRS, Université Pierreet Marie Curie, UMR 7590, Paris, France
| | - Edwige Otero
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Amandine Bellec
- Université Paris Cit é, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013, Paris, France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay 12 Cedex, France.
| |
Collapse
|
4
|
Trommer C, Kuhlemann E, Engesser TA, Walter M, Thakur S, Kuch W, Tuczek F. Spin crossover in dinuclear iron(II) complexes bridged by bis-bipyridine ligands: dimer effects on electronic structure, spectroscopic properties and spin-state switching. Dalton Trans 2024; 53:9909-9920. [PMID: 38808483 DOI: 10.1039/d4dt00707g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Inspired by the well-studied mononuclear spin crossover compound [Fe(H2B(pz)2)2(bipy)], the bipyridine-based bisbidentate ligands 1,2-di(2,2'-bipyridin-5-yl)ethyne (ac(bipy)2) and 1,4-di(2,2'-bipyridine-5-yl)-3,5-dimethoxybenzene (Ph(OMe)2(bipy)2) are used to bridge two [Fe(H2B(pz)2)2] units, leading to the charge-neutral dinuclear iron(II) compounds [{Fe(H2B(pz)2)2}2 μ-(ac(bipy)2)] (1) and [{Fe(H2B(pz)2)2}2 μ-(Ph(OMe)2(bipy)2)] (2), respectively. The spin-crossover properties of these molecules are investigated by temperature-dependent PPMS measurements, Mössbauer, vibrational and UV/Vis spectroscopy as well as X-ray absorption spectroscopy. While compound 1 undergoes complete SCO with T1/2 = 125 K, an incomplete spin transition is observed for 2 with an inflection point at 152 K and a remaining high-spin fraction of 40% below 65 K. The spin transitions of the dinuclear compounds are also more gradual than for the parent compound [Fe(H2B(pz)2)2(bipy)]. This is attributed to steric hindrance between the molecules, limiting intermolecular interactions such as π-π-stacking.
Collapse
Affiliation(s)
- Clara Trommer
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, D-24118 Kiel, Germany.
| | - Eike Kuhlemann
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, D-24118 Kiel, Germany.
| | - Tobias A Engesser
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, D-24118 Kiel, Germany.
| | - Marcel Walter
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.
| | - Sangeeta Thakur
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.
| | - Wolfgang Kuch
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.
| | - Felix Tuczek
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, D-24118 Kiel, Germany.
| |
Collapse
|
5
|
Zakrzewski J, Liberka M, Wang J, Chorazy S, Ohkoshi SI. Optical Phenomena in Molecule-Based Magnetic Materials. Chem Rev 2024; 124:5930-6050. [PMID: 38687182 PMCID: PMC11082909 DOI: 10.1021/acs.chemrev.3c00840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Since the last century, we have witnessed the development of molecular magnetism which deals with magnetic materials based on molecular species, i.e., organic radicals and metal complexes. Among them, the broadest attention was devoted to molecule-based ferro-/ferrimagnets, spin transition materials, including those exploring electron transfer, molecular nanomagnets, such as single-molecule magnets (SMMs), molecular qubits, and stimuli-responsive magnetic materials. Their physical properties open the application horizons in sensors, data storage, spintronics, and quantum computation. It was found that various optical phenomena, such as thermochromism, photoswitching of magnetic and optical characteristics, luminescence, nonlinear optical and chiroptical effects, as well as optical responsivity to external stimuli, can be implemented into molecule-based magnetic materials. Moreover, the fruitful interactions of these optical effects with magnetism in molecule-based materials can provide new physical cross-effects and multifunctionality, enriching the applications in optical, electronic, and magnetic devices. This Review aims to show the scope of optical phenomena generated in molecule-based magnetic materials, including the recent advances in such areas as high-temperature photomagnetism, optical thermometry utilizing SMMs, optical addressability of molecular qubits, magneto-chiral dichroism, and opto-magneto-electric multifunctionality. These findings are discussed in the context of the types of optical phenomena accessible for various classes of molecule-based magnetic materials.
Collapse
Affiliation(s)
- Jakub
J. Zakrzewski
- Faculty
of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
- Doctoral
School of Exact and Natural Sciences, Jagiellonian
University, Lojasiewicza
11, 30-348 Krakow, Poland
| | - Michal Liberka
- Faculty
of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
- Doctoral
School of Exact and Natural Sciences, Jagiellonian
University, Lojasiewicza
11, 30-348 Krakow, Poland
| | - Junhao Wang
- Department
of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, 1-1-1 Tonnodai, Tsukuba, Ibaraki 305-8573, Japan
| | - Szymon Chorazy
- Faculty
of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Shin-ichi Ohkoshi
- Department
of Chemistry, School of Science, The University
of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| |
Collapse
|
6
|
Gavara-Edo M, Valverde-Muñoz FJ, Muñoz MC, Elidrissi Moubtassim S, Marques-Moros F, Herrero-Martín J, Znovjyak K, Seredyuk M, Real JA, Coronado E. Design and Processing as Ultrathin Films of a Sublimable Iron(II) Spin Crossover Material Exhibiting Efficient and Fast Light-Induced Spin Transition. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:9591-9602. [PMID: 38047182 PMCID: PMC10687866 DOI: 10.1021/acs.chemmater.3c01704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 12/05/2023]
Abstract
Materials based on spin crossover (SCO) molecules have centered the attention in molecular magnetism for more than 40 years as they provide unique examples of multifunctional and stimuli-responsive materials, which can be then integrated into electronic devices to exploit their molecular bistability. This process often requires the preparation of thermally stable SCO molecules that can sublime and remain intact in contact with surfaces. However, the number of robust sublimable SCO molecules is still very scarce. Here, we report a novel example of this kind. It is based on a neutral iron(II) coordination complex formulated as [Fe(neoim)2], where neoimH is the ionogenic ligand 2-(1H-imidazol-2-yl)-9-methyl-1,10-phenanthroline. In the first part, a comprehensive study, which covers the synthesis and magnetostructural characterization of the [Fe(neoim)2] complex as a bulk microcrystalline material, is reported. Then, in the second part, we investigate the suitability of this material to form thin films through high-vacuum sublimation. Finally, the retainment of all present SCO capabilities in the bulk when the material is processed is thoroughly studied by means of X-ray absorption spectroscopy. In particular, a very efficient and fast light-induced spin transition (LIESST effect) has been observed, even for ultrathin films of 15 nm.
Collapse
Affiliation(s)
- Miguel Gavara-Edo
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
| | | | - M. Carmen Muñoz
- Departamento
de Fisica Aplicada, Universitat Politècnica
de València, Camino de Vera s/n, Valencia 46022, Spain
| | - Safaa Elidrissi Moubtassim
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
| | - Francisco Marques-Moros
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
| | | | - Kateryna Znovjyak
- Department
of Chemistry, Taras Shevchenko National
University of Kyiv, 64/13,
Volodymyrska Street, Kyiv 01601, Ukraine
| | - Maksym Seredyuk
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
- Department
of Chemistry, Taras Shevchenko National
University of Kyiv, 64/13,
Volodymyrska Street, Kyiv 01601, Ukraine
| | - José Antonio Real
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
| | - Eugenio Coronado
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
| |
Collapse
|
7
|
Johannsen S, Gruber M, Barreteau C, Seredyuk M, Antonio Real J, Markussen T, Berndt R. Spin-Crossover and Fragmentation of Fe(neoim) 2 on Silver and Gold. J Phys Chem Lett 2023; 14:7814-7823. [PMID: 37623823 DOI: 10.1021/acs.jpclett.3c01551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
The neutral spin crossover complex Fe(neoim)2, neoim being the deprotonated form of the ionogenic ligand 2-(1H-imidazol-2-yl)-9-methyl-1,10-phenanthroline (neoimH), is investigated on the (111) surfaces of Au and Ag using scanning tunneling microscopy and density functional theory calculations. The complex sublimates and adsorbs intact on Ag(111), where it exhibits an electron-induced spin crossover. However, it fragments on Au. According to density functional theory calculations, the adsorbed complex is drastically distorted by the interactions with the substrates, in particular by van der Waals forces. Dispersion interaction is also decisive for the relative stabilities of the low- and high-spin states of the adsorbed complex. The unexpected instability of the complex on the gold substrate is attributed to enhanced covalent bonding of the fragments to the substrate.
Collapse
Affiliation(s)
- Sven Johannsen
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität, 24098 Kiel, Germany
| | - Manuel Gruber
- Faculty of Physics and CENIDE, University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Cyrille Barreteau
- Université Paris-Saclay CEA, CNRS SPEC, 91191 Gif-sur-Yvette, France
| | - Maksym Seredyuk
- Instituto de Ciencia Molecular (ICMol)/Departamento de Química Inorgánica, Universidad de Valencia, 46980 Paterna, Valencia, Spain
- Department of Chemistry, Taras Shevchenko National University of Kyiv, 64/13 Volodymyrska Street 01601 Kyiv, Ukraine
| | - José Antonio Real
- Instituto de Ciencia Molecular (ICMol)/Departamento de Química Inorgánica, Universidad de Valencia, 46980 Paterna, Valencia, Spain
| | | | - Richard Berndt
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität, 24098 Kiel, Germany
| |
Collapse
|
8
|
Grunwald J, Torres J, Buchholz A, Näther C, Kämmerer L, Gruber M, Rohlf S, Thakur S, Wende H, Plass W, Kuch W, Tuczek F. Defying the inverse energy gap law: a vacuum-evaporable Fe(ii) low-spin complex with a long-lived LIESST state. Chem Sci 2023; 14:7361-7380. [PMID: 37416721 PMCID: PMC10321519 DOI: 10.1039/d3sc00561e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/25/2023] [Indexed: 07/08/2023] Open
Abstract
The novel vacuum-evaporable complex [Fe(pypypyr)2] (pypypyr = bipyridyl pyrrolide) was synthesised and analysed as bulk material and as a thin film. In both cases, the compound is in its low-spin state up to temperatures of at least 510 K. Thus, it is conventionally considered a pure low-spin compound. According to the inverse energy gap law, the half time of the light-induced excited high-spin state of such compounds at temperatures approaching 0 K is expected to be in the regime of micro- or nanoseconds. In contrast to these expectations, the light-induced high-spin state of the title compound has a half time of several hours. We attribute this behaviour to a large structural difference between the two spin states along with four distinct distortion coordinates associated with the spin transition. This leads to a breakdown of single-mode behaviour and thus drastically decreases the relaxation rate of the metastable high-spin state. These unprecedented properties open up new strategies for the development of compounds showing light-induced excited spin state trapping (LIESST) at high temperatures, potentially around room temperature, which is relevant for applications in molecular spintronics, sensors, displays and the like.
Collapse
Affiliation(s)
- Jan Grunwald
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel 24098 Kiel Germany +49 431 880 1520 +49 431 880 1410
| | - Jorge Torres
- Institut für Experimentalphysik, Freie Universität Berlin Arnimallee 14 14195 Berlin Germany +49 30 838 452098 +49 30 838 52098
| | - Axel Buchholz
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena 07743 Jena Germany
| | - Christian Näther
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel 24098 Kiel Germany +49 431 880 1520 +49 431 880 1410
| | - Lea Kämmerer
- Fakultät für Physik and CENIDE, Universität Duisburg-Essen 47048 Duisburg Germany
| | - Manuel Gruber
- Fakultät für Physik and CENIDE, Universität Duisburg-Essen 47048 Duisburg Germany
| | - Sebastian Rohlf
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel 24098 Kiel Germany
| | - Sangeeta Thakur
- Institut für Experimentalphysik, Freie Universität Berlin Arnimallee 14 14195 Berlin Germany +49 30 838 452098 +49 30 838 52098
| | - Heiko Wende
- Fakultät für Physik and CENIDE, Universität Duisburg-Essen 47048 Duisburg Germany
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena 07743 Jena Germany
| | - Wolfgang Kuch
- Institut für Experimentalphysik, Freie Universität Berlin Arnimallee 14 14195 Berlin Germany +49 30 838 452098 +49 30 838 52098
| | - Felix Tuczek
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel 24098 Kiel Germany +49 431 880 1520 +49 431 880 1410
| |
Collapse
|
9
|
Chen H, Yang HH, Frauhammer T, You H, Sun Q, Nagel P, Schuppler S, Gaspar AB, Real JA, Wulfhekel W. Observation of Exchange Interaction in Iron(II) Spin Crossover Molecules in Contact with Passivated Ferromagnetic Surface of Co/Au(111). SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2300251. [PMID: 36828799 DOI: 10.1002/smll.202300251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Indexed: 06/02/2023]
Abstract
Spin crossover (SCO) complexes sensitively react on changes of the environment by a change in the spin of the central metallic ion making them ideal candidates for molecular spintronics. In particular, the composite of SCO complexes and ferromagnetic (FM) surfaces would allow spin-state switching of the molecules in combination with the magnetic exchange interaction to the magnetic substrate. Unfortunately, when depositing SCO complexes on ferromagnetic surfaces, spin-state switching is blocked by the relatively strong interaction between the adsorbed molecules and the surface. Here, the Fe(II) SCO complex [FeII (Pyrz)2 ] (Pyrz = 3,5-dimethylpyrazolylborate) with sub-monolayer thickness in contact with a passivated FM film of Co on Au(111) is studied. In this case, the molecules preserve thermal spin crossover and at the same time the high-spin species show a sizable exchange interaction of > 0.9 T with the FM Co substrate. These observations provide a feasible design strategy in fabricating SCO-FM hybrid devices.
Collapse
Affiliation(s)
- Hongyan Chen
- Physikalisches Institut, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany
| | - Hung-Hsiang Yang
- Physikalisches Institut, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany
| | - Timo Frauhammer
- Physikalisches Institut, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany
| | - Haoran You
- Physikalisches Institut, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany
| | - Qing Sun
- Laboratory for Electron Microscopy, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany
| | - Peter Nagel
- Electron Spectroscopy Group, Institute for Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), 76021, Karlsruhe, Germany
- Karlsruhe Nano Micro Facility (KNMFi), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany
| | - Stefan Schuppler
- Electron Spectroscopy Group, Institute for Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), 76021, Karlsruhe, Germany
- Karlsruhe Nano Micro Facility (KNMFi), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany
| | - Ana Belén Gaspar
- Institut de Ciència Molecular (ICMol), Universitat de València, C/Catedrático José Beltrán Martínez 2, 46980, Paterna, Valencia, Spain
| | - José Antonio Real
- Institut de Ciència Molecular (ICMol), Universitat de València, C/Catedrático José Beltrán Martínez 2, 46980, Paterna, Valencia, Spain
| | - Wulf Wulfhekel
- Physikalisches Institut, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany
- Quantum Control Group, Institute for Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), 76021, Karlsruhe, Germany
| |
Collapse
|
10
|
Yazdani S, Phillips J, Ekanayaka TK, Cheng R, Dowben PA. The Influence of the Substrate on the Functionality of Spin Crossover Molecular Materials. Molecules 2023; 28:3735. [PMID: 37175145 PMCID: PMC10180229 DOI: 10.3390/molecules28093735] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/18/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
Spin crossover complexes are a route toward designing molecular devices with a facile readout due to the change in conductance that accompanies the change in spin state. Because substrate effects are important for any molecular device, there are increased efforts to characterize the influence of the substrate on the spin state transition. Several classes of spin crossover molecules deposited on different types of surface, including metallic and non-metallic substrates, are comprehensively reviewed here. While some non-metallic substrates like graphite seem to be promising from experimental measurements, theoretical and experimental studies indicate that 2D semiconductor surfaces will have minimum interaction with spin crossover molecules. Most metallic substrates, such as Au and Cu, tend to suppress changes in spin state and affect the spin state switching process due to the interaction at the molecule-substrate interface that lock spin crossover molecules in a particular spin state or mixed spin state. Of course, the influence of the substrate on a spin crossover thin film depends on the molecular film thickness and perhaps the method used to deposit the molecular film.
Collapse
Affiliation(s)
- Saeed Yazdani
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (S.Y.); (J.P.)
| | - Jared Phillips
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (S.Y.); (J.P.)
| | - Thilini K. Ekanayaka
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588-0299, USA;
| | - Ruihua Cheng
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (S.Y.); (J.P.)
| | - Peter A. Dowben
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588-0299, USA;
| |
Collapse
|
11
|
Kelai M, Tauzin A, Railean A, Repain V, Lagoute J, Girard Y, Rousset S, Otero E, Mallah T, Boillot ML, Enachescu C, Bellec A. Interface versus Bulk Light-Induced Switching in Spin-Crossover Molecular Ultrathin Films Adsorbed on a Metallic Surface. J Phys Chem Lett 2023; 14:1949-1954. [PMID: 36787373 DOI: 10.1021/acs.jpclett.2c03733] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Spin-crossover molecules present the unique property of having two spin states that can be controlled by light excitation at low temperature. Here, we report on the photoexcitation of [FeII((3, 5-(CH3)2Pz)3BH)2] (Pz = pyrazolyl) ultrathin films, with thicknesses ranging from 0.9 to 5.3 monolayers, adsorbed on Cu(111) substrate. Using X-ray absorption spectroscopy measurements, we confirm the anomalous light-induced spin-state switching observed for sub-monolayer coverage and demonstrate that it is confined to the first molecular layer in contact with the metallic substrate. For higher coverages, the well-known light-induced excited spin-state trapping effect is recovered. Combining continuous light excitation with thermal cycling, we demonstrate that at low temperature light-induced thermal hysteresis is measured for the thicker films, while for sub-monolayer coverage, the light enables extension of the thermal conversion over a large temperature range. Mechanoelastic simulations underline that, due to the intermolecular interactions, opposite behaviors are observed in the different layers composing the films.
Collapse
Affiliation(s)
- Massine Kelai
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Arthur Tauzin
- Université Paris-Saclay, Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, UMR 8182, 91400 Orsay, France
| | - Anastasia Railean
- Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Iasi 700506, Romania
| | - Vincent Repain
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Jérôme Lagoute
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Yann Girard
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Sylvie Rousset
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Edwige Otero
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Talal Mallah
- Université Paris-Saclay, Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, UMR 8182, 91400 Orsay, France
| | - Marie-Laure Boillot
- Université Paris-Saclay, Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, UMR 8182, 91400 Orsay, France
| | - Cristian Enachescu
- Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Iasi 700506, Romania
| | - Amandine Bellec
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| |
Collapse
|
12
|
Kumar B, Paul A, Mondal DJ, Paliwal P, Konar S. Spin-State Modulation in Fe II -Based Hofmann-Type Coordination Polymers: From Molecules to Materials. CHEM REC 2022; 22:e202200135. [PMID: 35815939 DOI: 10.1002/tcr.202200135] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/21/2022] [Indexed: 11/05/2022]
Abstract
Spin crossover complexes that reversibly interconvert between two stable states imitate a binary state of 0 and 1, delivering a promising possibility to address the data processing concept in smart materials. Thus, a comprehensive understanding of the modulation of magnetic transition between high spin and low spin and the factors responsible for stabilizing the spin states is an essential theme in modern materials design. In this context, the present review attempts to provide a concise outline of the design strategy employed at the molecular level for fine-tuning the spin-state switching in FeII -based Hofmann-type coordination polymers and their effects on the optical and magnetic response. In addition, development towards the nanoscale architectures of HCPs, i. e., in terms of nanoparticles and thin films, are emphasized to bridge the gap between the laboratory and reality.
Collapse
Affiliation(s)
- Bhart Kumar
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| | - Abhik Paul
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| | - Dibya Jyoti Mondal
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| | - Piyush Paliwal
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| | - Sanjit Konar
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| |
Collapse
|
13
|
Li P, Zhou L, Zhao C, Ju H, Gao Q, Si W, Cheng L, Hao J, Li M, Chen Y, Jia C, Guo X. Single-molecule nano-optoelectronics: insights from physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:086401. [PMID: 35623319 DOI: 10.1088/1361-6633/ac7401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Single-molecule optoelectronic devices promise a potential solution for miniaturization and functionalization of silicon-based microelectronic circuits in the future. For decades of its fast development, this field has made significant progress in the synthesis of optoelectronic materials, the fabrication of single-molecule devices and the realization of optoelectronic functions. On the other hand, single-molecule optoelectronic devices offer a reliable platform to investigate the intrinsic physical phenomena and regulation rules of matters at the single-molecule level. To further realize and regulate the optoelectronic functions toward practical applications, it is necessary to clarify the intrinsic physical mechanisms of single-molecule optoelectronic nanodevices. Here, we provide a timely review to survey the physical phenomena and laws involved in single-molecule optoelectronic materials and devices, including charge effects, spin effects, exciton effects, vibronic effects, structural and orbital effects. In particular, we will systematically summarize the basics of molecular optoelectronic materials, and the physical effects and manipulations of single-molecule optoelectronic nanodevices. In addition, fundamentals of single-molecule electronics, which are basic of single-molecule optoelectronics, can also be found in this review. At last, we tend to focus the discussion on the opportunities and challenges arising in the field of single-molecule optoelectronics, and propose further potential breakthroughs.
Collapse
Affiliation(s)
- Peihui Li
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Li Zhou
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Cong Zhao
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Hongyu Ju
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
- School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, People's Republic of China
| | - Qinghua Gao
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Wei Si
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Li Cheng
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Jie Hao
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Mengmeng Li
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Yijian Chen
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Chuancheng Jia
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, Beijing 100871, People's Republic of China
| | - Xuefeng Guo
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, Beijing 100871, People's Republic of China
| |
Collapse
|
14
|
Johannsen S, Ossinger S, Grunwald J, Herman A, Wende H, Tuczek F, Gruber M, Berndt R. Spin Crossover in a Cobalt Complex on Ag(111). Angew Chem Int Ed Engl 2022; 61:e202115892. [PMID: 35032345 PMCID: PMC9303790 DOI: 10.1002/anie.202115892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Indexed: 12/05/2022]
Abstract
The Co-based complex [Co(H2 B(pz)(pypz))2 ] (py=pyridine, pz=pyrazole) deposited on Ag(111) was investigated with scanning tunneling microscopy at ≈5 K. Due to a bis(tridentate) coordination sphere the molecules aggregate mainly into tetramers. Individual complexes in these tetramers undergo reversible transitions between two states with characteristic image contrasts when current is passed through them or one of their neighbors. Two molecules exhibit this bistability while the other two molecules are stable. The transition rates vary linearly with the tunneling current and exhibit an intriguing dependence on the bias voltage and its polarity. We interpret the states as being due to S=1 /2 and 3 /2 spin states of the Co2+ complex. The image contrast and the orders-of-magnitude variations of the switching yields can be tentatively understood from the calculated orbital structures of the two spin states, thus providing first insights into the mechanism of electron-induced excited spin-state trapping (ELIESST).
Collapse
Affiliation(s)
- Sven Johannsen
- Institut für Experimentelle und Angewandte PhysikChristian-Albrechts-Universität24098KielGermany
| | - Sascha Ossinger
- Institut für Anorganische ChemieChristian-Albrechts-Universität24098KielGermany
- Department of ChemistryUniversity of BaselSt. Johanns-Ring 194056BaselSwitzerland
| | - Jan Grunwald
- Institut für Anorganische ChemieChristian-Albrechts-Universität24098KielGermany
| | - Alexander Herman
- Faculty of Physics and CENIDEUniversity of Duisburg-Essen47057DuisburgGermany
| | - Heiko Wende
- Faculty of Physics and CENIDEUniversity of Duisburg-Essen47057DuisburgGermany
| | - Felix Tuczek
- Institut für Anorganische ChemieChristian-Albrechts-Universität24098KielGermany
| | - Manuel Gruber
- Institut für Experimentelle und Angewandte PhysikChristian-Albrechts-Universität24098KielGermany
- Faculty of Physics and CENIDEUniversity of Duisburg-Essen47057DuisburgGermany
| | - Richard Berndt
- Institut für Experimentelle und Angewandte PhysikChristian-Albrechts-Universität24098KielGermany
| |
Collapse
|
15
|
Johannsen S, Ossinger S, Grunwald J, Herman A, Wende H, Tuczek F, Gruber M, Berndt R. Spin Crossover in a Cobalt Complex on Ag(111). Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202115892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Sven Johannsen
- Institut für Experimentelle und Angewandte Physik Christian-Albrechts-Universität 24098 Kiel Germany
| | - Sascha Ossinger
- Institut für Anorganische Chemie Christian-Albrechts-Universität 24098 Kiel Germany
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Jan Grunwald
- Institut für Anorganische Chemie Christian-Albrechts-Universität 24098 Kiel Germany
| | - Alexander Herman
- Faculty of Physics and CENIDE University of Duisburg-Essen 47057 Duisburg Germany
| | - Heiko Wende
- Faculty of Physics and CENIDE University of Duisburg-Essen 47057 Duisburg Germany
| | - Felix Tuczek
- Institut für Anorganische Chemie Christian-Albrechts-Universität 24098 Kiel Germany
| | - Manuel Gruber
- Institut für Experimentelle und Angewandte Physik Christian-Albrechts-Universität 24098 Kiel Germany
- Faculty of Physics and CENIDE University of Duisburg-Essen 47057 Duisburg Germany
| | - Richard Berndt
- Institut für Experimentelle und Angewandte Physik Christian-Albrechts-Universität 24098 Kiel Germany
| |
Collapse
|
16
|
Ekanayaka TK, Kurz H, McElveen KA, Hao G, Mishra E, N'Diaye AT, Lai RY, Weber B, Dowben PA. Evidence for surface effects on the intermolecular interactions in Fe(II) spin crossover coordination polymers. Phys Chem Chem Phys 2022; 24:883-894. [PMID: 34908055 DOI: 10.1039/d1cp04243b] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
From X-ray absorption spectroscopy (XAS) and X-ray photoemission spectroscopy (XPS), it is evident that the spin state transition behavior of Fe(II) spin crossover coordination polymer crystallites at the surface differs from the bulk. A comparison of four different coordination polymers reveals that the observed surface properties may differ from bulk for a variety of reasons. There are Fe(II) spin crossover coordination polymers with either almost complete switching of the spin state at the surface or no switching at all. Oxidation, differences in surface packing, and changes in coordination could all contribute to making the surface very different from the bulk. Some Fe(II) spin crossover coordination polymers may be sufficiently photoactive so that X-ray spectroscopies cannot discern the spin state transition.
Collapse
Affiliation(s)
- Thilini K Ekanayaka
- Department of Physics and Astronomy, University of Nebraska, Jorgensen Hall, Lincoln, NE 68588-0299, USA.
| | - Hannah Kurz
- Inorganic Chemistry IV, University of Bayreuth, Universitätsstrasse 30, NW I, 95447 Bayreuth, Germany
| | - Kayleigh A McElveen
- Department of Chemistry, University of Nebraska, Hamilton Hall, Lincoln, NE 68588, USA
| | - Guanhua Hao
- Department of Physics and Astronomy, University of Nebraska, Jorgensen Hall, Lincoln, NE 68588-0299, USA. .,Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Esha Mishra
- Department of Physics and Astronomy, University of Nebraska, Jorgensen Hall, Lincoln, NE 68588-0299, USA.
| | - Alpha T N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Rebecca Y Lai
- Department of Chemistry, University of Nebraska, Hamilton Hall, Lincoln, NE 68588, USA.,Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Voetle-Keegan Nano Center, Lincoln, NE 68588, USA
| | - Birgit Weber
- Inorganic Chemistry IV, University of Bayreuth, Universitätsstrasse 30, NW I, 95447 Bayreuth, Germany
| | - Peter A Dowben
- Department of Physics and Astronomy, University of Nebraska, Jorgensen Hall, Lincoln, NE 68588-0299, USA.
| |
Collapse
|
17
|
Manipulating Selective Metal‐to‐Metal Electron Transfer to Achieve Multi‐Phase Transitions in an Asymmetric [Fe2Co]‐Assembled Mixed‐Valence Chain. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202115367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
18
|
Meng YS, Yao NT, Zhao L, Yi C, Liu Q, Li YM, Oshio H, Liu T. Manipulating Selective Metal-to-Metal Electron Transfer to Achieve Multi-Phase Transitions in an Asymmetric [Fe2Co]-Assembled Mixed-Valence Chain. Angew Chem Int Ed Engl 2021; 61:e202115367. [PMID: 34971479 DOI: 10.1002/anie.202115367] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Indexed: 11/08/2022]
Abstract
Manipulation of multi-functions in molecular materials is promising for future switching and memory devices, although is currently difficult. Herein, we assembled the asymmetric {Fe2Co} unit into a cyanide-bridged mixed-valence chain {[(Tp)Fe(CN)3]2Co(BIT)}·2CH3OH (1) (Tp = hydrotris(pyrazolyl)borate and BIT = 3,4-bis-(1H-imidazol-1-yl)thiophen), which showed reversible multi-phase transitions accompanied by the photo-switchable single-chain magnet property and dielectric anomalies. Variable temperature X-ray structural studies revealed thermo-and photo-induced selective electron transfer (ET) between the Co and one of the Fe ions. Alternating-current magnetic susceptibility studies revealed that 1 displayed on and off of the single-chain magnet behavior by alternating 946-nm and 532-nm light irradiations. A substantial anomaly in dielectric constant was discovered during the electron transfer process, which is uncommon in similar ET complexes. These findings illustrate that 1 provided a new platform for multi-phase transitions and multi-switches adjusted by selective metal-to-metal ET.
Collapse
Affiliation(s)
- Yin-Shan Meng
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, 2 Linggong Rd., Dalian, 116024, China., 116024, Dalian, CHINA
| | - Nian-Tao Yao
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Liang Zhao
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Cheng Yi
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Qiang Liu
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Ya-Ming Li
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Hiroki Oshio
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Tao Liu
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| |
Collapse
|
19
|
Ekanayaka TK, Wang P, Yazdani S, Phillips JP, Mishra E, Dale AS, N'Diaye AT, Klewe C, Shafer P, Freeland J, Streubel R, Wampler JP, Zapf V, Cheng R, Shatruk M, Dowben PA. Evidence of dynamical effects and critical field in a cobalt spin crossover complex. Chem Commun (Camb) 2021; 58:661-664. [PMID: 34914817 DOI: 10.1039/d1cc05309d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The [Co(SQ)2(4-CN-py)2] complex exhibits dynamical effects over a wide range of temperature. The orbital moment, determined by X-ray magnetic circular dichroism (XMCD) with decreasing applied magnetic field, indicates a nonzero critical field for net alignment of magnetic moments, an effect not seen with the spin moment of [Co(SQ)2(4-CN-py)2].
Collapse
Affiliation(s)
- Thilini K Ekanayaka
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588-0299, USA.
| | - Ping Wang
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306, USA
| | - Saeed Yazdani
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, USA
| | - Jared Paul Phillips
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, USA
| | - Esha Mishra
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588-0299, USA.
| | - Ashley S Dale
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, USA
| | - Alpha T N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Christoph Klewe
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - John Freeland
- Argonne National Laboratory, Advanced Photon Source, Bldg. 431/E003, 9700 South Cass Ave., Argonne, IL 60439, USA
| | - Robert Streubel
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588-0299, USA. .,Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - James Paris Wampler
- National High Magnetic Field Lab, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA
| | - Vivien Zapf
- National High Magnetic Field Lab, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA
| | - Ruihua Cheng
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, USA
| | - Michael Shatruk
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306, USA
| | - Peter A Dowben
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588-0299, USA.
| |
Collapse
|
20
|
Zhao Y, Gobbi M, Hueso LE, Samorì P. Molecular Approach to Engineer Two-Dimensional Devices for CMOS and beyond-CMOS Applications. Chem Rev 2021; 122:50-131. [PMID: 34816723 DOI: 10.1021/acs.chemrev.1c00497] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two-dimensional materials (2DMs) have attracted tremendous research interest over the last two decades. Their unique optical, electronic, thermal, and mechanical properties make 2DMs key building blocks for the fabrication of novel complementary metal-oxide-semiconductor (CMOS) and beyond-CMOS devices. Major advances in device functionality and performance have been made by the covalent or noncovalent functionalization of 2DMs with molecules: while the molecular coating of metal electrodes and dielectrics allows for more efficient charge injection and transport through the 2DMs, the combination of dynamic molecular systems, capable to respond to external stimuli, with 2DMs makes it possible to generate hybrid systems possessing new properties by realizing stimuli-responsive functional devices and thereby enabling functional diversification in More-than-Moore technologies. In this review, we first introduce emerging 2DMs, various classes of (macro)molecules, and molecular switches and discuss their relevant properties. We then turn to 2DM/molecule hybrid systems and the various physical and chemical strategies used to synthesize them. Next, we discuss the use of molecules and assemblies thereof to boost the performance of 2D transistors for CMOS applications and to impart diverse functionalities in beyond-CMOS devices. Finally, we present the challenges, opportunities, and long-term perspectives in this technologically promising field.
Collapse
Affiliation(s)
- Yuda Zhao
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 allée Gaspard Monge, F-67000 Strasbourg, France.,School of Micro-Nano Electronics, ZJU-Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, 310027 Hangzhou, People's Republic of China
| | - Marco Gobbi
- Centro de Fisica de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 Donostia-San Sebastián, Spain.,CIC nanoGUNE, E-20018 Donostia-San Sebastian, Basque Country, Spain.,IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Luis E Hueso
- CIC nanoGUNE, E-20018 Donostia-San Sebastian, Basque Country, Spain.,IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Paolo Samorì
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 allée Gaspard Monge, F-67000 Strasbourg, France
| |
Collapse
|
21
|
Sánchez-de-Armas R, Montenegro-Pohlhammer N, Develioglu A, Burzurí E, Calzado CJ. Spin-crossover complexes in nanoscale devices: main ingredients of the molecule-substrate interactions. NANOSCALE 2021; 13:18702-18713. [PMID: 34739026 DOI: 10.1039/d1nr04577f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Spin-crossover complexes embedded in nanodevices experience effects that are absent in the bulk that can modulate, quench and even suppress the spin-transition. In this work we explore, by means of state-of-the-art quantum chemistry calculations, different aspects of the integration of SCO molecules on active nanodevices, such as the geometry and energetics of the interaction with the substrate, extension of the charge transfer between the substrate and SCO molecule, impact of the applied external electric field on the spin-transition, and sensitivity of the transport properties on the local conditions of the substrate. We focus on the recently reported encapsulation of Fe(II) spin-crossover complexes in single-walled carbon nanotubes, with new measurements that support the theoretical findings. Even so our results could be useful to many other systems where SCO phenomena take place at the nanoscale, the spin-state switching is probed by an external electric field or current, or the substrate is responsible for the quenching of the SCO mechanism.
Collapse
Affiliation(s)
- Rocío Sánchez-de-Armas
- Departamento de Química Física. U. Sevilla, calle Prof. García González, s/n, 41012 Sevilla, Spain.
| | - Nicolás Montenegro-Pohlhammer
- Departamento de Química Física. U. Sevilla, calle Prof. García González, s/n, 41012 Sevilla, Spain.
- Laboratory of Theoretical Chemistry, Faculty of Chemistry and Biology, University of Santiago de Chile (USACH), 9170022, Santiago, Chile
| | - Aysegul Develioglu
- IMDEA Nanociencia, Campus de Cantoblanco, Calle Faraday 9, 28049 Madrid, Spain.
| | - Enrique Burzurí
- IMDEA Nanociencia, Campus de Cantoblanco, Calle Faraday 9, 28049 Madrid, Spain.
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Carmen J Calzado
- Departamento de Química Física. U. Sevilla, calle Prof. García González, s/n, 41012 Sevilla, Spain.
| |
Collapse
|
22
|
Zhang Y. Fe(phen) 2(NCS) 2 on Al(100): influence of AlN layer on spin crossover barrier. Phys Chem Chem Phys 2021; 23:23758-23767. [PMID: 34643204 DOI: 10.1039/d1cp03782j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We study how a nitride layer affects spin crossover (SCO) in a single Fe(phen)2(NCS)2 (Fephen) molecule adsorbed on the Al(100) surface using ab initio calculations. The Coulomb correlation of the open-shell 3d electrons has been considered using a Hubbard-U correction within different exchange-correlation approximations, including the van der Waals density functional. We determine the SCO energy barrier by computing the minimum energy path between the high-spin (HS) and low-spin (LS) states via direct constraint relaxations. It is shown that the HS-LS energy difference is slightly increased once deposited on Al(100), and thus LS states tend to be stabilized, as usually observed on metallic substrates. The oxidation of metallic Al to aluminum ions in the AlN layer promotes molecular adsorption, while it decreases HS-LS splitting, making Fephen switchable between its two spin states. Due to enhanced molecule-substrate bonding, the SCO barrier height is considerably increased, which may promote cooperativity. This effect is consistent with the AlN facilitated charge transfer at the interface that results from a reduction in surface work function. Our findings reveal the crucial role that surface electronic structure plays in maintaining spin bistability of the molecular adsorbate.
Collapse
Affiliation(s)
- Yachao Zhang
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Education University, Guiyang 550018, China.
| |
Collapse
|
23
|
Bhandary S, Tomczak JM, Valli A. Designing a mechanically driven spin-crossover molecular switch via organic embedding. NANOSCALE ADVANCES 2021; 3:4990-4995. [PMID: 34485819 PMCID: PMC8386408 DOI: 10.1039/d1na00407g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/25/2021] [Indexed: 06/13/2023]
Abstract
Among spin-crossover complexes, Fe-porphyrin (FeP) stands out for molecular spintronic applications: an intricate, yet favourable balance between ligand fields, charge transfer, and the Coulomb interaction makes FeP highly manipulable, while its planar structure facilitates device integration. Here, we theoretically design a mechanical spin-switch device in which external strain triggers the intrinsic magneto-structural coupling of FeP through a purely organic embedding. Exploiting the chemical compatibility and stretchability of graphene nanoribbon electrodes, we overcome common reliability and reproducibility issues of conventional inorganic setups. The competition between the Coulomb interaction and distortion-induced changes in ligand fields requires methodologies beyond the state-of-the-art: combining density functional theory with many-body techniques, we demonstrate experimentally feasible tensile strain to trigger a low-spin (S = 1) to high-spin (S = 2) crossover. Concomitantly, the current through the device toggles by over an order of magnitude, adding a fully planar mechanical current-switch unit to the panoply of molecular spintronics.
Collapse
Affiliation(s)
- Sumanta Bhandary
- School of Physics, Trinity College Dublin, The University of Dublin Dublin 2 Ireland +353-1-896 8455
| | - Jan M Tomczak
- Institute of Solid State Physics, Vienna University of Technology 1040 Vienna Austria
| | - Angelo Valli
- Institute for Theoretical Physics, Vienna University of Technology 1040 Vienna Austria
| |
Collapse
|
24
|
Johannsen S, Ossinger S, Markussen T, Tuczek F, Gruber M, Berndt R. Electron-Induced Spin-Crossover in Self-Assembled Tetramers. ACS NANO 2021; 15:11770-11778. [PMID: 34133115 DOI: 10.1021/acsnano.1c02698] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The spin crossover compound Fe(H2B(pyrazole)(pyridylpyrazole))2 was investigated in detail on Ag(111) with scanning tunneling microscopy (STM). A large fraction of the deposited molecules condenses into gridlike tetramers. Two molecules of each tetramer may be converted between two states by current injection. We attribute this effect to a spin transition. This interpretation is supported by control experiments on the analogous, magnetically passive Zn compound that forms virtually identical tetramers but exhibits no switching. The switching yields were studied for various electron energies, and the resulting values exceed those reported from other SCO systems by 2 orders of magnitude. The other two molecules of a tetramer were immutable. However, they may be used as contacts for current injection that leads to conversion of one of their neighbors. This "remote" switching is fairly efficient with yields reduced by only one to two orders of magnitude compared to direct excitation of a switchable molecule. We present a model of the tetramer structure that reproduces key observations from the experiments. In particular, sterical blocking prevents spin crossover of two molecules of a tetramer. Density functional theory calculations show that the model indeed represents a minimum energy structure. They also reproduce STM images and corroborate a remote-switching mechanism that is based on electron transfer between molecules.
Collapse
Affiliation(s)
- Sven Johannsen
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität, 24098 Kiel, Germany
| | - Sascha Ossinger
- Institut für Anorganische Chemie, Christian-Albrechts-Universität, 24098 Kiel, Germany
| | - Troels Markussen
- Synopsys Denmark, Fruebjergvej 3, Postbox 4, DK-2100 Copenhagen, Denmark
| | - Felix Tuczek
- Institut für Anorganische Chemie, Christian-Albrechts-Universität, 24098 Kiel, Germany
| | - Manuel Gruber
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität, 24098 Kiel, Germany
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Richard Berndt
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität, 24098 Kiel, Germany
| |
Collapse
|
25
|
Kelai M, Repain V, Tauzin A, Li W, Girard Y, Lagoute J, Rousset S, Otero E, Sainctavit P, Arrio MA, Boillot ML, Mallah T, Enachescu C, Bellec A. Thermal Bistability of an Ultrathin Film of Iron(II) Spin-Crossover Molecules Directly Adsorbed on a Metal Surface. J Phys Chem Lett 2021; 12:6152-6158. [PMID: 34184899 DOI: 10.1021/acs.jpclett.1c01366] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Spin-crossover molecules are very attractive compounds to realize multifunctional spintronic devices. Understanding their properties when deposited on metals is therefore crucial for their future rational implementation as ultrathin films in such devices. Using X-ray absorption spectroscopy, we study the thermal transition of the spin-crossover compound FeII((3,5-(CH3)2Pz)3BH)2 from submonolayer to multilayers on a Cu(111) substrate. We determine how the residual fraction of high spin molecules at low temperature, as well as the bistability range and the temperature of switching, depends on the layer thickness. The most spectacular effect is the clear opening of a 35 ± 9 K thermal hysteresis loop for a 3.0 ± 0.7 monolayers thick film. To better understand the role played by the substrate and the dimensionality on the thermal bistability, we have performed Monte Carlo Arrhenius simulations in the framework of a mechanoelastic model that include a molecule-substrate interaction. This model reproduces well the main features observed experimentally and can predict how the spin-crossover transition is modified by the thickness and the substrate interaction.
Collapse
Affiliation(s)
- Massine Kelai
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Vincent Repain
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Arthur Tauzin
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ Paris Sud, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France
| | - Weibin Li
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR7590, Sorbonne Université, MNHN, 75252 Paris Cedex 5, France
| | - Yann Girard
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Jérôme Lagoute
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Sylvie Rousset
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Edwige Otero
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Philippe Sainctavit
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR7590, Sorbonne Université, MNHN, 75252 Paris Cedex 5, France
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Marie-Anne Arrio
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR7590, Sorbonne Université, MNHN, 75252 Paris Cedex 5, France
| | - Marie-Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ Paris Sud, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ Paris Sud, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France
| | - Cristian Enachescu
- Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Iasi, 700506, Romania
| | - Amandine Bellec
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| |
Collapse
|
26
|
Kipgen L, Bernien M, Tuczek F, Kuch W. Spin-Crossover Molecules on Surfaces: From Isolated Molecules to Ultrathin Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008141. [PMID: 33963619 PMCID: PMC11468565 DOI: 10.1002/adma.202008141] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/22/2021] [Indexed: 06/12/2023]
Abstract
Molecular spintronics seeks to use single or few molecules as functional building blocks for spintronic applications, directly relying on molecular properties or properties of interfaces between molecules and inorganic electrodes. Spin-crossover molecules (SCMs) are one of the most promising classes of candidates for molecular spintronics due to their bistability deriving from the existence of two spin states that can be reversibly switched by temperature, light, electric fields, etc. Building devices based on single or few molecules would entail connecting the molecule(s) with solid surfaces and understanding the fundamental behavior of the resulting assemblies. Herein, the investigations of SCMs on solid surfaces, ranging from isolated single molecules (submonolayers) to ultrathin films (mainly in the sub-10 nm range) are summarized. The achievements, challenges and prospects in this field are highlighted.
Collapse
Affiliation(s)
- Lalminthang Kipgen
- Institut für ExperimentalphysikFreie Universität BerlinArnimallee 1414195BerlinGermany
- Present address:
Laboratoire Matériaux et Phénomènes QuantiquesUniversité de Paris ‐ CNRS10 rue Alice Domon et Léonie Duquet75013ParisFrance
| | - Matthias Bernien
- Institut für ExperimentalphysikFreie Universität BerlinArnimallee 1414195BerlinGermany
| | - Felix Tuczek
- Institut für Anorganische ChemieChristian‐Albrechts‐Universität zu KielMax‐Eyth‐Straße 224118KielGermany
| | - Wolfgang Kuch
- Institut für ExperimentalphysikFreie Universität BerlinArnimallee 1414195BerlinGermany
| |
Collapse
|
27
|
Montenegro-Pohlhammer N, Sánchez-de-Armas R, Calzado CJ, Borges-Martínez M, Cárdenas-Jirón G. A photo-induced spin crossover based molecular switch and spin filter operating at room temperature. Dalton Trans 2021; 50:6578-6587. [PMID: 33899067 DOI: 10.1039/d1dt00078k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Since Venkataramani et al. (Science, 2011, 331(6016), 445-448) reported reversible, room-temperature light-induced spin crossover in Ni-porphyrin functionalized with a phenylazopyridine ligand (NiTPP-PAPy), this complex has attracted the attention of many researchers due to its potential applications in molecular-based devices. In this work, we perform a detailed study, by means of DFT and WFT methodologies, focused on the deposition of NiTP-PAPy over an Au(111) surface, followed by DFT-NEGF calculations employing a gold surface and the tip of an STM as electrodes, in order to probe the deposited complex's transport properties. Our DFT calculations show that not only the metalled porphyrin is strongly adsorbed on the surface, in both the high (HS) and low spin (LS) configurations, but also, and more importantly, photoinduced switching is preserved upon adsorption, a fact that is also confirmed through WFT and TD-DFT calculations. Moreover, our DFT-NEGF calculations indicate that the current passing through the molecular junction-like systems is much higher in the HS configuration than in the LS one, along with the fact that the current calculated in the ferromagnetic junction is highly spin-polarized. These remarkable transport properties suggest that the complex could be used as a component in molecular switches based on the total current passing through the system, modulated by light irradiation, spin filters due to the spin polarization of the carriers in the HS configuration, or even in two-step rectifiers combining the two features mentioned above, all of these operating at room temperature, giving to this complex the potential to be an active element in all kinds of future spintronic devices.
Collapse
Affiliation(s)
- Nicolás Montenegro-Pohlhammer
- Laboratory of Theoretical Chemistry, Faculty of Chemistry and Biology, University of Santiago de Chile (USACH), 9170022, Santiago, Chile.
| | | | | | | | | |
Collapse
|
28
|
Kumar KS, Ruben M. Sublimable Spin-Crossover Complexes: From Spin-State Switching to Molecular Devices. Angew Chem Int Ed Engl 2021; 60:7502-7521. [PMID: 31769131 PMCID: PMC8048919 DOI: 10.1002/anie.201911256] [Citation(s) in RCA: 134] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Indexed: 11/10/2022]
Abstract
Spin-crossover (SCO) active transition metal complexes are an important class of switchable molecular materials due to their bistable spin-state switching characteristics at or around room temperature. Vacuum-sublimable SCO complexes are a subclass of SCO complexes suitable for fabricating ultraclean spin-switchable films desirable for applications, especially in molecular electronics/spintronics. Consequently, on-surface SCO of thin-films of sublimable SCO complexes have been studied employing spectroscopy and microscopy techniques, and results of fundamental and technological importance have been obtained. This Review provides complete coverage of advances made in the field of vacuum-sublimable SCO complexes: progress made in the design and synthesis of sublimable functional SCO complexes, on-surface SCO of molecular and multilayer thick films, and various molecular and thin-film device architectures based on the sublimable SCO complexes.
Collapse
Affiliation(s)
- Kuppusamy Senthil Kumar
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS)CNRS-Université de Strasbourg23, rue du Loess, BP 4367034Strasbourg cedex 2France
| | - Mario Ruben
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS)CNRS-Université de Strasbourg23, rue du Loess, BP 4367034Strasbourg cedex 2France
- Institute of NanotechnologyKarlsruhe Institute of Technology (KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany
- Institute of Quantum Materials and -TechnologyKarlsruhe Institute of Technology (KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany
| |
Collapse
|
29
|
Villalva J, Develioglu A, Montenegro-Pohlhammer N, Sánchez-de-Armas R, Gamonal A, Rial E, García-Hernández M, Ruiz-Gonzalez L, Costa JS, Calzado CJ, Pérez EM, Burzurí E. Spin-state-dependent electrical conductivity in single-walled carbon nanotubes encapsulating spin-crossover molecules. Nat Commun 2021; 12:1578. [PMID: 33707459 PMCID: PMC7952721 DOI: 10.1038/s41467-021-21791-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 02/04/2021] [Indexed: 11/09/2022] Open
Abstract
Spin crossover (SCO) molecules are promising nanoscale magnetic switches due to their ability to modify their spin state under several stimuli. However, SCO systems face several bottlenecks when downscaling into nanoscale spintronic devices: their instability at the nanoscale, their insulating character and the lack of control when positioning nanocrystals in nanodevices. Here we show the encapsulation of robust Fe-based SCO molecules within the 1D cavities of single-walled carbon nanotubes (SWCNT). We find that the SCO mechanism endures encapsulation and positioning of individual heterostructures in nanoscale transistors. The SCO switch in the guest molecules triggers a large conductance bistability through the host SWCNT. Moreover, the SCO transition shifts to higher temperatures and displays hysteresis cycles, and thus memory effect, not present in crystalline samples. Our results demonstrate how encapsulation in SWCNTs provides the backbone for the readout and positioning of SCO molecules into nanodevices, and can also help to tune their magnetic properties at the nanoscale.
Collapse
Affiliation(s)
| | | | | | | | | | - Eduardo Rial
- IMDEA Nanociencia, Campus de Cantoblanco, Madrid, Spain
| | - Mar García-Hernández
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Luisa Ruiz-Gonzalez
- Departamento de Quimica Inorgánica, Universidad Complutense de Madrid, Madrid, Spain
| | | | - Carmen J Calzado
- Departamento de Química Física, Universidad de Sevilla, Sevilla, Spain.
| | - Emilio M Pérez
- IMDEA Nanociencia, Campus de Cantoblanco, Madrid, Spain.
| | | |
Collapse
|
30
|
Nonvolatile Voltage Controlled Molecular Spin-State Switching for Memory Applications. MAGNETOCHEMISTRY 2021. [DOI: 10.3390/magnetochemistry7030037] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nonvolatile, molecular multiferroic devices have now been demonstrated, but it is worth giving some consideration to the issue of whether such devices could be a competitive alternative for solid-state nonvolatile memory. For the Fe (II) spin crossover complex [Fe{H2B(pz)2}2(bipy)], where pz = tris(pyrazol-1-yl)-borohydride and bipy = 2,2′-bipyridine, voltage-controlled isothermal changes in the electronic structure and spin state have been demonstrated and are accompanied by changes in conductance. Higher conductance is seen with [Fe{H2B(pz)2}2(bipy)] in the high spin state, while lower conductance occurs for the low spin state. Plausibly, there is the potential here for low-cost molecular solid-state memory because the essential molecular thin films are easily fabricated. However, successful device fabrication does not mean a device that has a practical value. Here, we discuss the progress and challenges yet facing the fabrication of molecular multiferroic devices, which could be considered competitive to silicon.
Collapse
|
31
|
Gebretsadik T, Yang Q, Wu J, Tang J. Hydrazone based spin crossover complexes: Behind the extra flexibility of the hydrazone moiety to switch the spin state. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213666] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
32
|
Palomino CM, Sánchez-de-Armas R, Calzado CJ. Theoretical inspection of the spin-crossover [Fe(tzpy) 2(NCS) 2] complex on Au(100) surface. J Chem Phys 2021; 154:034701. [PMID: 33499621 DOI: 10.1063/5.0036612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We explore the deposition of the spin-crossover [Fe(tzpy)2(NCS)2] complex on the Au(100) surface by means of density functional theory (DFT) based calculations. Two different routes have been employed: low-cost finite cluster-based calculations, where both the Fe complex and the surface are maintained fixed while the molecule approaches the surface; and periodic DFT plane-wave calculations, where the surface is represented by a four-layer slab and both the molecule and surface are relaxed. Our results show that the bridge adsorption site is preferred over the on-top and fourfold hollow ones for both spin states, although they are energetically close. The LS molecule is stabilized by the surface, and the HS-LS energy difference is enhanced by about 15%-25% once deposited. The different Fe ligand field for LS and HS molecules manifests on the composition and energy of the low-lying bands. Our simulated STM images indicate that it is possible to distinguish the spin state of the deposited molecules by tuning the bias voltage of the STM tip. Finally, it should be noted that the use of a reduced size cluster to simulate the Au(100) surface proves to be a low-cost and reliable strategy, providing results in good agreement with those resulting from state-of-the-art periodic calculations for this system.
Collapse
Affiliation(s)
- Carlos M Palomino
- Departamento de Química Física, c/Profesor García González, s/n 41012 Sevilla, Spain
| | | | - Carmen J Calzado
- Departamento de Química Física, c/Profesor García González, s/n 41012 Sevilla, Spain
| |
Collapse
|
33
|
Shang Y, Xu X, Gao B, Wang S, Duan X. Single-atom catalysis in advanced oxidation processes for environmental remediation. Chem Soc Rev 2021; 50:5281-5322. [DOI: 10.1039/d0cs01032d] [Citation(s) in RCA: 240] [Impact Index Per Article: 80.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This review presents the recent advances in synthetic strategies, characterisation, and computations of carbon-based single-atom catalysts, as well as their innovative applications and mechanisms in advanced oxidation technologies.
Collapse
Affiliation(s)
- Yanan Shang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse
- School of Environmental Science and Engineering
- Shandong University
- Jinan 250100
- P. R. China
| | - Xing Xu
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse
- School of Environmental Science and Engineering
- Shandong University
- Jinan 250100
- P. R. China
| | - Baoyu Gao
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse
- School of Environmental Science and Engineering
- Shandong University
- Jinan 250100
- P. R. China
| | - Shaobin Wang
- School of Chemical Engineering and Advanced Materials
- The University of Adelaide
- Adelaide
- Australia
| | - Xiaoguang Duan
- School of Chemical Engineering and Advanced Materials
- The University of Adelaide
- Adelaide
- Australia
| |
Collapse
|
34
|
Nakaya M, Ohtani R, Lindoy LF, Hayami S. Light-induced excited spin state trapping in iron(iii) complexes. Inorg Chem Front 2021. [DOI: 10.1039/d0qi01188f] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This review discusses the correlation of the local and whole molecular structure of iron(iii) complexes with the magnetic properties including the light-induced excited spin-state trapping (LIESST) effect.
Collapse
Affiliation(s)
- Manabu Nakaya
- Department of Chemistry
- Faculty of Science
- Josai University
- Sakado
- Japan
| | - Ryo Ohtani
- Department of Chemistry
- Faculty of Science
- Kyushu University
- Fukuoka 819-0395
- Japan
| | | | - Shinya Hayami
- Department of Chemistry
- Faculty of Advanced Science and Technology
- Kumamoto University
- Kumamoto 860-8555
- Japan
| |
Collapse
|
35
|
López-Moreno A, del Carmen Giménez-López M. Metallic-based magnetic switches under confinement. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2021. [DOI: 10.1016/bs.adomc.2021.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
36
|
Montenegro‐Pohlhammer N, Sánchez‐de‐Armas R, Calzado CJ. Deposition of the Spin Crossover Fe
II
–Pyrazolylborate Complex on Au(111) Surface at the Molecular Level. Chemistry 2020; 27:712-723. [DOI: 10.1002/chem.202003520] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/21/2020] [Indexed: 01/01/2023]
Affiliation(s)
| | - Rocío Sánchez‐de‐Armas
- Departamento de Química Física Universidad de Sevilla, c/ Profesor García González, s/n. 41012 Sevilla Spain
| | - Carmen J. Calzado
- Departamento de Química Física Universidad de Sevilla, c/ Profesor García González, s/n. 41012 Sevilla Spain
| |
Collapse
|
37
|
Karuppannan SK, Martín-Rodríguez A, Ruiz E, Harding P, Harding DJ, Yu X, Tadich A, Cowie B, Qi D, Nijhuis CA. Room temperature conductance switching in a molecular iron(iii) spin crossover junction. Chem Sci 2020; 12:2381-2388. [PMID: 34164002 PMCID: PMC8179334 DOI: 10.1039/d0sc04555a] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Herein, we report the first room temperature switchable Fe(iii) molecular spin crossover (SCO) tunnel junction. The junction is constructed from [FeIII(qsal-I)2]NTf2 (qsal-I = 4-iodo-2-[(8-quinolylimino)methyl]phenolate) molecules self-assembled on graphene surfaces with conductance switching of one order of magnitude associated with the high and low spin states of the SCO complex. Normalized conductance analysis of the current–voltage characteristics as a function of temperature reveals that charge transport across the SCO molecule is dominated by coherent tunnelling. Temperature-dependent X-ray absorption spectroscopy and density functional theory confirm the SCO complex retains its SCO functionality on the surface implying that van der Waals molecule—electrode interfaces provide a good trade-off between junction stability while retaining SCO switching capability. These results provide new insights and may aid in the design of other types of molecular devices based on SCO compounds. Herein, we report the first room temperature switchable Fe(iii) molecular spin crossover (SCO) tunnel junction.![]()
Collapse
Affiliation(s)
- Senthil Kumar Karuppannan
- Department of Chemistry, National University of Singapore 3 Science Drive Singapore 117543 Singapore
| | - Alejandro Martín-Rodríguez
- Departament de Química Inorgànica, Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
| | - Eliseo Ruiz
- Departament de Química Inorgànica, Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
| | - Phimphaka Harding
- Functional Materials and Nanotechnology Center of Excellence, Walailak University Thasala Nakhon Si Thammarat 80160 Thailand
| | - David J Harding
- Functional Materials and Nanotechnology Center of Excellence, Walailak University Thasala Nakhon Si Thammarat 80160 Thailand
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore 5 Research Link Singapore 117603 Singapore
| | - Anton Tadich
- Australian Synchrotron Clayton Victoria 3168 Australia
| | - Bruce Cowie
- School of Chemistry and Physics, Queensland University of Technology Brisbane Queensland 4001 Australia
| | - Dongchen Qi
- School of Chemistry and Physics, Queensland University of Technology Brisbane Queensland 4001 Australia
| | - Christian A Nijhuis
- Department of Chemistry, National University of Singapore 3 Science Drive Singapore 117543 Singapore .,Centre for Advanced 2D Materials & Graphene Research, National University of Singapore 6 Science Drive 2 Singapore 117546 Singapore
| |
Collapse
|
38
|
Kumar KS, Ruben M. Sublimierbare Spin‐Crossover‐Komplexe: Vom Schalten des Spinzustands zu molekularen Bauelementen. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201911256] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Kuppusamy Senthil Kumar
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) CNRS-Université de Strasbourg 23, rue du Loess, BP 43 67034 Strasbourg cedex 2 Frankreich
| | - Mario Ruben
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) CNRS-Université de Strasbourg 23, rue du Loess, BP 43 67034 Strasbourg cedex 2 Frankreich
- Institut für Nanotechnologie Karlsruher Institut für Technologie (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Deutschland
- Institut für Quantenmaterialien und -technologien Karlsruher Institut für Technologie (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Deutschland
| |
Collapse
|
39
|
Brandl T, Johannsen S, Häussinger D, Suryadevara N, Prescimone A, Bernhard S, Gruber M, Ruben M, Berndt R, Mayor M. Iron in a Cage: Fixation of a Fe(II)tpy 2 Complex by Fourfold Interlinking. Angew Chem Int Ed Engl 2020; 59:15947-15952. [PMID: 32412664 PMCID: PMC7540000 DOI: 10.1002/anie.202006340] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Indexed: 11/18/2022]
Abstract
The coordination sphere of the Fe(II) terpyridine complex 1 is rigidified by fourfold interlinking of both terpyridine ligands. Profiting from an octa-aldehyde precursor complex, the ideal dimensions of the interlinking structures are determined by reversible Schiff-base formation, before irreversible Wittig olefination provided the rigidified complex. Reversed-phase HPLC enables the isolation of the all-trans isomer of the Fe(II) terpyridine complex 1, which is fully characterized. While temperature independent low-spin states were recorded with superconducting quantum interference device (SQUID) measurements for both, the open precursor 8 and the interlinked complex 1, evidence of the increased rigidity of the ligand sphere in 1 was provided by proton T2 relaxation NMR experiments. The ligand sphere fixation in the macrocyclized complex 1 even reaches a level resisting substantial deformation upon deposition on an Au(111) surface, as demonstrated by its pristine form in a low temperature ultra-high vacuum scanning tunneling microscope experiment.
Collapse
Affiliation(s)
- Thomas Brandl
- Department of ChemistryUniversity of BaselSt. Johanns-Ring 194056BaselSwitzerland
| | - Sven Johannsen
- Institut für Experimentelle und Angewandte PhysikChristian-Albrechts-Universität zu KielLeibnizstr. 1924098KielGermany
| | - Daniel Häussinger
- Department of ChemistryUniversity of BaselSt. Johanns-Ring 194056BaselSwitzerland
| | - Nithin Suryadevara
- Institute of NanotechnologyKarlsruhe Institute of Technology (KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany
| | | | - Stefan Bernhard
- Department of ChemistryCarnegie Mellon UniversityPittsburghPA15213USA
| | - Manuel Gruber
- Institut für Experimentelle und Angewandte PhysikChristian-Albrechts-Universität zu KielLeibnizstr. 1924098KielGermany
| | - Mario Ruben
- Institute of NanotechnologyKarlsruhe Institute of Technology (KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS)CNRS-Université de Strasbourg23, rue de Loess, BP 4367034Strasbourg cedex 2France
| | - Richard Berndt
- Institut für Experimentelle und Angewandte PhysikChristian-Albrechts-Universität zu KielLeibnizstr. 1924098KielGermany
| | - Marcel Mayor
- Department of ChemistryUniversity of BaselSt. Johanns-Ring 194056BaselSwitzerland
- Institute of NanotechnologyKarlsruhe Institute of Technology (KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany
- Lehn Institute of Functional MaterialsSchool of ChemistrySun Yat-Sen UniversityGuangzhou510275China
| |
Collapse
|
40
|
Abstract
The transfer of the inherent bistability of spin crossover compounds to surfaces has attracted considerable interest in recent years. The deposition of the complexes on surfaces allows investigating them individually and to further understand the microscopic mechanisms at play. Moreover, it offers the prospect of engineering switchable functional surfaces. We review recent progress in the field with a particular focus on the challenges and limits associated with the dominant experimental techniques used, namely near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and scanning tunneling microscopy (STM). One of the main difficulties in NEXAFS-based experiments is to ascertain that the complexes are in direct contact with the surfaces. We show that molecular coverage determination based on the amplitude of the edge-jump of interest is challenging because the latter quantity depends on the substrate. Furthermore, NEXAFS averages the signals of a large number of molecules, which may be in different states. In particular, we highlight that the signal of fragmented molecules is difficult to distinguish from that of intact and functional ones. In contrast, STM allows investigating individual complexes, but the identification of the spin states is at best done indirectly. As quite some of the limits of the techniques are becoming apparent as the field is gaining maturity, their detailed descriptions will be useful for future investigations and for taking a fresh look at earlier reports.
Collapse
|
41
|
Brandl T, Johannsen S, Häussinger D, Suryadevara N, Prescimone A, Bernhard S, Gruber M, Ruben M, Berndt R, Mayor M. Iron in a Cage: Fixation of a Fe(II)tpy
2
Complex by Fourfold Interlinking. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Thomas Brandl
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Sven Johannsen
- Institut für Experimentelle und Angewandte Physik Christian-Albrechts-Universität zu Kiel Leibnizstr. 19 24098 Kiel Germany
| | - Daniel Häussinger
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Nithin Suryadevara
- Institute of Nanotechnology Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
| | - Alessandro Prescimone
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Stefan Bernhard
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Manuel Gruber
- Institut für Experimentelle und Angewandte Physik Christian-Albrechts-Universität zu Kiel Leibnizstr. 19 24098 Kiel Germany
| | - Mario Ruben
- Institute of Nanotechnology Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) CNRS-Université de Strasbourg 23, rue de Loess, BP 43 67034 Strasbourg cedex 2 France
| | - Richard Berndt
- Institut für Experimentelle und Angewandte Physik Christian-Albrechts-Universität zu Kiel Leibnizstr. 19 24098 Kiel Germany
| | - Marcel Mayor
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
- Institute of Nanotechnology Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
- Lehn Institute of Functional Materials School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
| |
Collapse
|
42
|
Zhang L, Tong Y, Kelai M, Bellec A, Lagoute J, Chacon C, Girard Y, Rousset S, Boillot M, Rivière E, Mallah T, Otero E, Arrio M, Sainctavit P, Repain V. Anomalous Light‐Induced Spin‐State Switching for Iron(II) Spin‐Crossover Molecules in Direct Contact with Metal Surfaces. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003896] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Luqiong Zhang
- Institut de Minéralogie, de Physique des Matériaux et, de Cosmochimie, CNRS UMR7590 Sorbonne Université, MNHN 75252 Paris Cedex 5 France
| | - Yongfeng Tong
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Massine Kelai
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Amandine Bellec
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Jérôme Lagoute
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Cyril Chacon
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Yann Girard
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Sylvie Rousset
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Marie‐Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay Univ Paris Sud Université Paris-Saclay CNRS, UMR 8182 91405 Orsay Cedex France
| | - Eric Rivière
- Institut de Chimie Moléculaire et des Matériaux d'Orsay Univ Paris Sud Université Paris-Saclay CNRS, UMR 8182 91405 Orsay Cedex France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay Univ Paris Sud Université Paris-Saclay CNRS, UMR 8182 91405 Orsay Cedex France
| | - Edwige Otero
- Synchrotron SOLEIL L'Orme des Merisiers Saint-Aubin 91192 Gif sur Yvette France
| | - Marie‐Anne Arrio
- Institut de Minéralogie, de Physique des Matériaux et, de Cosmochimie, CNRS UMR7590 Sorbonne Université, MNHN 75252 Paris Cedex 5 France
| | - Philippe Sainctavit
- Institut de Minéralogie, de Physique des Matériaux et, de Cosmochimie, CNRS UMR7590 Sorbonne Université, MNHN 75252 Paris Cedex 5 France
- Synchrotron SOLEIL L'Orme des Merisiers Saint-Aubin 91192 Gif sur Yvette France
| | - Vincent Repain
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| |
Collapse
|
43
|
Zhang L, Tong Y, Kelai M, Bellec A, Lagoute J, Chacon C, Girard Y, Rousset S, Boillot M, Rivière E, Mallah T, Otero E, Arrio M, Sainctavit P, Repain V. Anomalous Light‐Induced Spin‐State Switching for Iron(II) Spin‐Crossover Molecules in Direct Contact with Metal Surfaces. Angew Chem Int Ed Engl 2020; 59:13341-13346. [DOI: 10.1002/anie.202003896] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/22/2020] [Indexed: 01/11/2023]
Affiliation(s)
- Luqiong Zhang
- Institut de Minéralogie, de Physique des Matériaux et, de Cosmochimie, CNRS UMR7590 Sorbonne Université, MNHN 75252 Paris Cedex 5 France
| | - Yongfeng Tong
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Massine Kelai
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Amandine Bellec
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Jérôme Lagoute
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Cyril Chacon
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Yann Girard
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Sylvie Rousset
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| | - Marie‐Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay Univ Paris Sud Université Paris-Saclay CNRS, UMR 8182 91405 Orsay Cedex France
| | - Eric Rivière
- Institut de Chimie Moléculaire et des Matériaux d'Orsay Univ Paris Sud Université Paris-Saclay CNRS, UMR 8182 91405 Orsay Cedex France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay Univ Paris Sud Université Paris-Saclay CNRS, UMR 8182 91405 Orsay Cedex France
| | - Edwige Otero
- Synchrotron SOLEIL L'Orme des Merisiers Saint-Aubin 91192 Gif sur Yvette France
| | - Marie‐Anne Arrio
- Institut de Minéralogie, de Physique des Matériaux et, de Cosmochimie, CNRS UMR7590 Sorbonne Université, MNHN 75252 Paris Cedex 5 France
| | - Philippe Sainctavit
- Institut de Minéralogie, de Physique des Matériaux et, de Cosmochimie, CNRS UMR7590 Sorbonne Université, MNHN 75252 Paris Cedex 5 France
- Synchrotron SOLEIL L'Orme des Merisiers Saint-Aubin 91192 Gif sur Yvette France
| | - Vincent Repain
- Université de Paris Laboratoire Matériaux et Phénomènes Quantiques, CNRS 75013 Paris France
| |
Collapse
|
44
|
Beniwal S, Sarkar S, Baier F, Weber B, Dowben PA, Enders A. Site selective adsorption of the spin crossover complex Fe(phen)2(NCS) on Au(111). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:324003. [PMID: 32189641 DOI: 10.1088/1361-648x/ab808d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 03/17/2020] [Indexed: 06/10/2023]
Abstract
The iron(II) spin crossover complex Fe(1,10-phenanthroline)2(NCS)2, dubbed Fe-phen, has been studied with scanning tunneling microscopy, after adsorption on the 'herringbone' reconstructed surface of Au(111) for sub-monolayer coverages. The Fe-phen molecules attach, through their NCS-groups, to the Au atoms of the fcc domains of the reconstructed surface only, thereby lifting the herringbone reconstruction. The molecules stack to form 1D chains, which run along the Au[110] directions. Neighboring Fe-phen molecules are separated by approximately 2.65 nm, corresponding to 9 atomic spacings in this direction. The molecular axis, defined by the two phenanthroline groups, is aligned perpendicular to the chain axis, along the Au221¯direction, thereby bridging over 5 atomic spacings, in this direction. Experimental evidence suggests that the molecular spins are locked in a mixed state in the sub-monolayer regime at temperatures between 100 K and 300 K.
Collapse
Affiliation(s)
- Sumit Beniwal
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588, United States of America
| | - Suchetana Sarkar
- Department of Physics, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Felix Baier
- Department of Physics, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Birgit Weber
- Department of Chemistry, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Peter A Dowben
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588, United States of America
| | - Axel Enders
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588, United States of America
- Department of Physics, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| |
Collapse
|
45
|
Göbel C, Hils C, Drechsler M, Baabe D, Greiner A, Schmalz H, Weber B. Confined Crystallization of Spin-Crossover Nanoparticles in Block-Copolymer Micelles. Angew Chem Int Ed Engl 2020; 59:5765-5770. [PMID: 31891660 PMCID: PMC7155125 DOI: 10.1002/anie.201914343] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Indexed: 12/31/2022]
Abstract
Nanoparticles of the spin-crossover coordination polymer [FeL(bipy)]n were synthesized by confined crystallization within the core of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer micelles. The 4VP units in the micellar core act as coordination sites for the Fe complex. In the bulk material, the spin-crossover nanoparticles in the core are well isolated from each other allowing thermal treatment without disintegration of their structure. During annealing above the glass transition temperature of the PS block, the transition temperature is shifted gradually to higher temperatures from the as-synthesized product (T1/2 ↓=163 K and T1/2 ↑=170 K) to the annealed product (T1/2 ↓=203 K and T1/2 ↑=217 K) along with an increase in hysteresis width from 6 K to 14 K. Thus, the spin-crossover properties can be shifted towards the properties of the related bulk material. The stability of the nanocomposite allows further processing, such as electrospinning from solution.
Collapse
Affiliation(s)
- Christoph Göbel
- Department of Chemistry, Inorganic Chemistry IV, Unversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
| | - Christian Hils
- Department of Chemistry, Macromolecular Chemistry IIUniversität BayreuthUniversitätsstr. 3095440BayreuthGermany
| | - Markus Drechsler
- Keylab Electron and Optical Microscopy, Bavarian Polymer InstituteUniversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
| | - Dirk Baabe
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Andreas Greiner
- Department of Chemistry, Macromolecular Chemistry II and Keylab Synthesis and Molecular Characterization, Bavarian Polymer InstituteUniversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
| | - Holger Schmalz
- Department of Chemistry, Macromolecular Chemistry II and Keylab Synthesis and Molecular Characterization, Bavarian Polymer InstituteUniversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
| | - Birgit Weber
- Department of Chemistry, Inorganic Chemistry IV, Unversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
| |
Collapse
|
46
|
Göbel C, Hils C, Drechsler M, Baabe D, Greiner A, Schmalz H, Weber B. Confined Crystallization of Spin‐Crossover Nanoparticles in Block‐Copolymer Micelles. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914343] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Christoph Göbel
- Department of Chemistry, Inorganic Chemistry IV, Unversität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
| | - Christian Hils
- Department of Chemistry, Macromolecular Chemistry II Universität Bayreuth Universitätsstr. 30 95440 Bayreuth Germany
| | - Markus Drechsler
- Keylab Electron and Optical Microscopy, Bavarian Polymer Institute Universität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
| | - Dirk Baabe
- Institut für Anorganische und Analytische Chemie Technische Universität Braunschweig Hagenring 30 38106 Braunschweig Germany
| | - Andreas Greiner
- Department of Chemistry, Macromolecular Chemistry II and Keylab Synthesis and Molecular Characterization, Bavarian Polymer Institute Universität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
| | - Holger Schmalz
- Department of Chemistry, Macromolecular Chemistry II and Keylab Synthesis and Molecular Characterization, Bavarian Polymer Institute Universität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
| | - Birgit Weber
- Department of Chemistry, Inorganic Chemistry IV, Unversität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
| |
Collapse
|
47
|
Ossinger S, Kipgen L, Naggert H, Bernien M, Britton AJ, Nickel F, Arruda LM, Kumberg I, Engesser TA, Golias E, Näther C, Tuczek F, Kuch W. Effect of ligand methylation on the spin-switching properties of surface-supported spin-crossover molecules. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:114003. [PMID: 31778990 DOI: 10.1088/1361-648x/ab5c92] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
X-ray absorption spectroscopy investigations of the spin-state switching of spin-crossover (SCO) complexes adsorbed on a highly-oriented pyrolytic graphite (HOPG) surface have shown so far that HOPG is a promising candidate to realize applications such as spintronic devices because of the stability of SCO complexes on HOPG and the possibility of highly efficient thermal and light-induced spin-state switching. Herein, we present the spin switching of several Fe(II) SCO complexes adsorbed on an HOPG surface with particular emphasis on the thermally induced spin transition behaviour with respect to different structural modifications. The complexes of the type [Fe(bpz)2(L)] (bpz = dihydrobis(pyrazolyl)borate, L = 1,10-phenanthroline, 2,2'-bipyridine) and their methylated derivatives exhibit SCO in the solid state with some differences regarding cooperative effects. However, in the vacuum-deposited thick films on quartz, complete and more gradual spin transition behavior is observable via UV/vis spectroscopy. In contrast to that, all complexes show large differences upon direct contact with HOPG. Whereas the unmodified complexes show thermal and light-induced SCO, the addition of e.g. two or four methyl groups leads to a partial or a complete loss of the SCO on the surface. The angle-dependent measurement of the N K-edge compared to calculations indicates that the complete SCO and HS-locked molecules on the surface exhibit a similar preferential orientation, whereas complexes undergoing an incomplete SCO exhibit a random orientation on the surface. These results are discussed in the light of molecule-substrate interactions.
Collapse
Affiliation(s)
- Sascha Ossinger
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118 Kiel, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Cini A, Poggini L, Chumakov AI, Rüffer R, Spina G, Wattiaux A, Duttine M, Gonidec M, Fittipaldi M, Rosa P, Mannini M. Synchrotron-based Mössbauer spectroscopy characterization of sublimated spin crossover molecules. Phys Chem Chem Phys 2020; 22:6626-6637. [PMID: 32159166 DOI: 10.1039/c9cp04464g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The spin crossover (SCO) efficiency of [57Fe(bpz)2(phen)] (where bpz = bis(pyrazol-1-yl)borohydride and phen = 9,10-phenantroline) molecules deposited on gold substrates was investigated by means of synchrotron Mössbauer spectroscopy. The spin transition was driven thermally, or light induced via the LIESST (light induced excited spin-state trapping) effect. Both sets of measurements show that, once deposited on a gold substrate, the efficiency of the SCO mechanism is modified with respect to molecules in the bulk phase. A correlation in the distribution of hyperfine parameters in the sublimated films, not evidenced so far in the bulk phase, is reported. This translates into geometrical distortions of the first coordination sphere of the iron atom that seem to correlate with the decreased spin conversion. The work reported clearly shows the potentiality of synchrotron Mössbauer spectroscopy for the characterization of nanostructured Fe-based SCO systems, thus resulting as a key tool in view of their applications in innovative nanoscale devices.
Collapse
Affiliation(s)
- Alberto Cini
- Department of Physics and Astronomy, University of Florence and INSTM Research Unit of Florence, via Sansone 1, I-50019 Sesto Fiorentino (FI), Italy.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
van Geest EP, Shakouri K, Fu W, Robert V, Tudor V, Bonnet S, Schneider GF. Contactless Spin Switch Sensing by Chemo-Electric Gating of Graphene. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1903575. [PMID: 32011060 DOI: 10.1002/adma.201903575] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 12/16/2019] [Indexed: 06/10/2023]
Abstract
Direct electrical probing of molecular materials is often impaired by their insulating nature. Here, graphene is interfaced with single crystals of a molecular spin crossover complex, [Fe(bapbpy)(NCS)2 ], to electrically detect phase transitions in the molecular crystal through the variation of graphene resistance. Contactless sensing is achieved by separating the crystal from graphene with an insulating polymer spacer. Next to mechanical effects, which influence the conductivity of the graphene sheet but can be minimized by using a thicker spacer, a Dirac point shift in graphene is observed experimentally upon spin crossover. As confirmed by computational modeling, this Dirac point shift is due to the phase-dependent electrostatic potential generated by the crystal inside the graphene sheet. This effect, named as chemo-electric gating, suggests that molecular materials may serve as substrates for designing graphene-based electronic devices. Chemo-electric gating, thus, opens up new possibilities to electrically probe chemical and physical processes in molecular materials in a contactless fashion, from a large distance, which can enhance their use in technological applications, for example, as sensors.
Collapse
Affiliation(s)
- Erik P van Geest
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Khosrow Shakouri
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Wangyang Fu
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Vincent Robert
- Laboratoire de Chimie Quantique, Université de Strasbourg, CNRS, UMR 7177, 67081, Strasbourg, France
| | - Viorica Tudor
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Sylvestre Bonnet
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Grégory F Schneider
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
| |
Collapse
|
50
|
Ossinger S, Näther C, Tuczek F. Spin-crossover behavior of bis[dihydrobis(4-methylpyrazol-1-yl-borate)]-(2,2'-bipyridine)iron and analogous complexes in the bulk and in thin films: Elucidating the influence of π-π-interactions on the type of spin transition. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:094001. [PMID: 31722328 DOI: 10.1088/1361-648x/ab5776] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The new complex [Fe(H2B(4-CH3-pz)2)2(bipy)] (1, pz = pyrazole, bipy = 2,2'-bipyridine) is synthesized and investigated by temperature-dependent magnetic measurements, Mößbauer, electronic absorption and vibrational spectroscopy as well as single crystal x-ray diffraction. In the crystal structure of 1 the complexes are pairwise linked to dimers by intermolecular π-π interactions between their bipyridine ligands, with a shortest intradimer distance between two neighboring pyridine rings of 3.575 Å. Analysis of the crystal structures of related iron(II) bis(dihydrobis(pyrazoyl)borate) complexes reveals that most of them contain similar dimers, and that at short π-π intra-dimer distances the complexes are locked in the high-spin state whereas at long distances complete thermal spin crossover (SCO) is observed. Compound 1 with an intermediate π-π intra-dimer distance shows incomplete SCO in the bulk but complete SCO in vacuum-deposited thin films where intermolecular interactions are absent. The implications of this remarkable structure-property relationship are discussed.
Collapse
Affiliation(s)
- Sascha Ossinger
- Institute of Inorganic Chemistry, Christian-Albrechts-University Kiel, Max-Eyth-Str. 2, 24118 Kiel, Germany
| | | | | |
Collapse
|