1
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Tong Y, Kelaï M, Bairagi K, Repain V, Lagoute J, Girard Y, Rousset S, Boillot ML, Mallah T, Enachescu C, Bellec A. Voltage-Induced Bistability of Single Spin-Crossover Molecules in a Two-Dimensional Monolayer. J Phys Chem Lett 2021; 12:11029-11034. [PMID: 34743521 DOI: 10.1021/acs.jpclett.1c03271] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bistable spin-crossover molecules are particularly interesting for the development of innovative electronic and spintronic devices as they present two spin states that can be controlled by external stimuli. In this paper, we report the voltage-induced switching of the high spin/low spin electronic states of spin-crossover molecules self-assembled in dense 2D networks on Au(111) and Cu(111) by scanning tunneling microscopy at low temperature. On Au(111), voltage pulses lead to the nonlocal switching of the molecules from any─high or low─spin state to the other followed by a spontaneous relaxation toward their initial state within minutes. On the other hand, on Cu(111), single molecules can be addressed at will. They retain their new electronic configuration after a voltage pulse. The memory effect demonstrated on Cu(111) is due to an interplay between long-range intermolecular interaction and molecule/substrate coupling as confirmed by mechanoelastic simulations.
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Affiliation(s)
- Yongfeng Tong
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Massine Kelaï
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Kaushik Bairagi
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Vincent Repain
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Jérôme Lagoute
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Yann Girard
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Sylvie Rousset
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Marie-Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, 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
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
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2
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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 DOI: 10.1002/adma.202008141] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [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.
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Affiliation(s)
- Lalminthang Kipgen
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Matthias Bernien
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Felix Tuczek
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118, Kiel, Germany
| | - Wolfgang Kuch
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
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3
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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]
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4
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Zhang X, Willke P, Singha A, Wolf C, Esat T, Choi M, Heinrich AJ, Choi T. Probing Magnetism in Artificial Metal-Organic Complexes Using Electronic Spin Relaxometry. J Phys Chem Lett 2020; 11:5618-5624. [PMID: 32578990 DOI: 10.1021/acs.jpclett.0c01281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Single spins are considered as a versatile candidate for miniaturizing information devices down to the nanoscale. To engineer the spin's properties, metal-organic frameworks provide a promising route which in turn requires thorough understanding of the metal-molecule interaction. Here, we investigate the magnetic robustness of a single iron (Fe) atom in artificially built Fe-tetracyanoethylene (TCNE) complexes by using low-temperature scanning tunneling microscopy (STM). We find that the magnetic anisotropy and spin relaxation dynamics of the Fe atom within the complexes remain unperturbed in comparison to well-isolated Fe atoms. Density functional theory (DFT) calculations support our experimental findings, suggesting that the 3d orbitals of the Fe atom remain largely undisturbed while the 4s and 4p orbitals are rearranged in the process of forming a complex. To precisely determine the location of the spin center within the complex, we utilize STM-based spin relaxometry, mapping out the spatial dependence of spin relaxation with subnanometer resolution. Our work suggests that the magnetic properties of atoms can remain unchanged while being embedded in a weakly bound molecular framework.
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Affiliation(s)
- Xue Zhang
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Philip Willke
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Aparajita Singha
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Christoph Wolf
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Taner Esat
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Minhee Choi
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Andreas J Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Taeyoung Choi
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
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5
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Taylor MG, Yang T, Lin S, Nandy A, Janet JP, Duan C, Kulik HJ. Seeing Is Believing: Experimental Spin States from Machine Learning Model Structure Predictions. J Phys Chem A 2020; 124:3286-3299. [PMID: 32223165 PMCID: PMC7311053 DOI: 10.1021/acs.jpca.0c01458] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Determination of ground-state spins
of open-shell transition-metal
complexes is critical to understanding catalytic and materials properties
but also challenging with approximate electronic structure methods.
As an alternative approach, we demonstrate how structure alone can
be used to guide assignment of ground-state spin from experimentally
determined crystal structures of transition-metal complexes. We first
identify the limits of distance-based heuristics from distributions
of metal–ligand bond lengths of over 2000 unique mononuclear
Fe(II)/Fe(III) transition-metal complexes. To overcome these limits,
we employ artificial neural networks (ANNs) to predict spin-state-dependent
metal–ligand bond lengths and classify experimental ground-state
spins based on agreement of experimental structures with the ANN predictions.
Although the ANN is trained on hybrid density functional theory data,
we exploit the method-insensitivity of geometric properties to enable
assignment of ground states for the majority (ca. 80–90%) of
structures. We demonstrate the utility of the ANN by data-mining the
literature for spin-crossover (SCO) complexes, which have experimentally
observed temperature-dependent geometric structure changes, by correctly
assigning almost all (>95%) spin states in the 46 Fe(II) SCO complex
set. This approach represents a promising complement to more conventional
energy-based spin-state assignment from electronic structure theory
at the low cost of a machine learning model.
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Affiliation(s)
- Michael G Taylor
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Tzuhsiung Yang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Sean Lin
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Aditya Nandy
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jon Paul Janet
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Chenru Duan
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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6
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Nandy A, Chu DBK, Harper DR, Duan C, Arunachalam N, Cytter Y, Kulik HJ. Large-scale comparison of 3d and 4d transition metal complexes illuminates the reduced effect of exchange on second-row spin-state energetics. Phys Chem Chem Phys 2020; 22:19326-19341. [DOI: 10.1039/d0cp02977g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The origin of distinct 3d vs. 4d transition metal complex sensitivity to exchange is explored over a large data set.
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Affiliation(s)
- Aditya Nandy
- Department of Chemical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
- Department of Chemistry
| | - Daniel B. K. Chu
- Department of Chemical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
| | - Daniel R. Harper
- Department of Chemical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
- Department of Chemistry
| | - Chenru Duan
- Department of Chemical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
- Department of Chemistry
| | - Naveen Arunachalam
- Department of Chemical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
| | - Yael Cytter
- Department of Chemical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
| | - Heather J. Kulik
- Department of Chemical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
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7
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Fourmental C, Mondal S, Banerjee R, Bellec A, Garreau Y, Coati A, Chacon C, Girard Y, Lagoute J, Rousset S, Boillot ML, Mallah T, Enachescu C, Barreteau C, Dappe YJ, Smogunov A, Narasimhan S, Repain V. Importance of Epitaxial Strain at a Spin-Crossover Molecule-Metal Interface. J Phys Chem Lett 2019; 10:4103-4109. [PMID: 31265299 DOI: 10.1021/acs.jpclett.9b01303] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Spin-crossover molecules are very appealing for use in multifunctional spintronic devices because of their ability to switch between high-spin and low-spin states with external stimuli such as voltage and light. In actual devices, the molecules are deposited on a substrate, which can modify their properties. However, surprisingly little is known about such molecule-substrate effects. Here we show for the first time, by grazing incidence X-ray diffraction, that an FeII spin-crossover molecular layer displays a well-defined epitaxial relationship with a metal substrate. Then we show, by both density functional calculations and a mechanoelastic model, that the resulting epitaxial strain and the related internal pressure can induce a partial spin conversion at low temperatures, which has indeed been observed experimentally. Our results emphasize the importance of substrate-induced spin state transitions and raise the possibility of exploiting them.
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Affiliation(s)
- Cynthia Fourmental
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Sourav Mondal
- Theoretical Sciences Unit and School of Advanced Materials , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore 560064 , India
| | - Rajdeep Banerjee
- Theoretical Sciences Unit and School of Advanced Materials , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore 560064 , India
| | - Amandine Bellec
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Yves Garreau
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
- Synchrotron SOLEIL , L'Orme des Merisiers, Saint-Aubin , 91192 Gif sur Yvette , France
| | - Alessandro Coati
- Synchrotron SOLEIL , L'Orme des Merisiers, Saint-Aubin , 91192 Gif sur Yvette , France
| | - Cyril Chacon
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Yann Girard
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Jérôme Lagoute
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Sylvie Rousset
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 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
| | - 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
| | - Cyrille Barreteau
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay , 91191 Cedex Gif sur Yvette , France
| | - Yannick J Dappe
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay , 91191 Cedex Gif sur Yvette , France
| | - Alexander Smogunov
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay , 91191 Cedex Gif sur Yvette , France
| | - Shobhana Narasimhan
- Theoretical Sciences Unit and School of Advanced Materials , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore 560064 , India
| | - Vincent Repain
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
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8
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Mikolasek M, Ridier K, Bessas D, Cerantola V, Félix G, Chaboussant G, Piedrahita-Bello M, Angulo-Cervera E, Godard L, Nicolazzi W, Salmon L, Molnár G, Bousseksou A. Phase Stability of Spin-Crossover Nanoparticles Investigated by Synchrotron Mössbauer Spectroscopy and Small-Angle Neutron Scattering. J Phys Chem Lett 2019; 10:1511-1515. [PMID: 30883126 DOI: 10.1021/acs.jpclett.9b00335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Spin-crossover nanomaterials have been actively studied in the past decade for their potential technological applications in sensing, actuating, and information processing devices. Unfortunately, an increasing number of the metallic centers become inactive at reduced sizes, presumably due to surface effects, limiting their switching ability and thus the scope of applications. Here we report on the investigation of "frozen" metallic centers in nanoparticles (2-80 nm size) of the spin-crossover compound Fe(pyrazine)[Ni(CN)4]. Magnetic measurements reveal both high-spin and low-spin residual fractions at atmospheric pressure. A pressure-induced transition of the high-spin residue is observed at around 1.5 GPa by synchrotron Mössbauer spectroscopy. We show that it is equivalent to a downshift of the transition temperature by ca. 400 K due to the size reduction. Unexpectedly, small-angle neutron scattering experiments demonstrate that these high-spin residual centers are not confined to the surface, which contradicts general theoretical considerations.
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Affiliation(s)
- Mirko Mikolasek
- ESRF-The European Synchrotron , CS40220, 38043 Grenoble Cedex 9, France
| | - Karl Ridier
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Dimitrios Bessas
- ESRF-The European Synchrotron , CS40220, 38043 Grenoble Cedex 9, France
| | - Valerio Cerantola
- ESRF-The European Synchrotron , CS40220, 38043 Grenoble Cedex 9, France
| | - Gautier Félix
- Institut Charles Gerhardt Montpellier, UMR 5253, Ingénierie Moléculaire et Nano-Objets , Université de Montpellier, ENSCM, CNRS , Place E. Bataillon , 34095 Montpellier Cedex 5, France
| | | | - Mario Piedrahita-Bello
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Elias Angulo-Cervera
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Léa Godard
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - William Nicolazzi
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Lionel Salmon
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Gábor Molnár
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Azzedine Bousseksou
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
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9
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Schaefer AW, Ehudin MA, Quist DA, Tang JA, Karlin KD, Solomon EI. Spin Interconversion of Heme-Peroxo-Copper Complexes Facilitated by Intramolecular Hydrogen-Bonding Interactions. J Am Chem Soc 2019; 141:4936-4951. [PMID: 30836005 PMCID: PMC6457345 DOI: 10.1021/jacs.9b00118] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Synthetic peroxo-bridged high-spin (HS) heme-(μ-η2:η1-O22-)-Cu(L) complexes incorporating (as part of the copper ligand) intramolecular hydrogen-bond (H-bond) capabilities and/or steric effects are herein demonstrated to affect the complex's electronic and geometric structure, notably impacting the spin state. An H-bonding interaction with the peroxo core favors a low-spin (LS) heme-(μ-η1:η1-O22-)-Cu(L) structure, resulting in a reversible temperature-dependent interconversion of spin state (5 coordinate HS to 6 coordinate LS). The LS state dominates at low temperatures, even in the absence of a strong trans-axial heme ligand. Lewis base addition inhibits the H-bond facilitated spin interconversion by competition for the H-bond donor, illustrating the precise H-bonding interaction required to induce spin-crossover (SCO). Resonance Raman spectroscopy (rR) shows that the H-bonding pendant interacts with the bridging peroxide ligand to stabilize the LS but not the HS state. The H-bond (to the Cu-bound O atom) acts to weaken the O-O bond and strengthen the Fe-O bond, exhibiting ν(M-O) and ν(O-O) values comparable to analogous known LS complexes with a strong donating trans-axial ligand, 1,5-dicyclohexylimidazole, (DCHIm)heme-(μ-η1:η1-O22-)-Cu(L). Variable-temperature (-90 to -130 °C) UV-vis and 2H NMR spectroscopies confirm the SCO process and implicate the involvement of solvent binding. Examining a case of solvent binding without SCO, thermodynamic parameters were obtained from a van't Hoff analysis, accounting for its contribution in SCO. Taken together, these data provide evidence for the H-bond group facilitating a core geometry change and allowing solvent to bind, stabilizing a LS state. The rR data, complemented by DFT analysis, reveal a stronger H-bonding interaction with the peroxo core in the LS compared to the HS complexes, which enthalpically favors the LS state. These insights enhance our fundamental understanding of secondary coordination sphere influences in metalloenzymes.
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Affiliation(s)
- Andrew W. Schaefer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Melanie A. Ehudin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - David A. Quist
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Joel A. Tang
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kenneth D. Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Edward I. Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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10
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Nandy A, Duan C, Janet JP, Gugler S, Kulik HJ. Strategies and Software for Machine Learning Accelerated Discovery in Transition Metal Chemistry. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b04015] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Aditya Nandy
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Chenru Duan
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jon Paul Janet
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Stefan Gugler
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Heather J. Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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11
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Knecht P, Suryadevara N, Zhang B, Reichert J, Ruben M, Barth JV, Klyatskaya S, Papageorgiou AC. The self-assembly and metal adatom coordination of a linear bis-tetrazole ligand on Ag(111). Chem Commun (Camb) 2018; 54:10072-10075. [PMID: 30132771 DOI: 10.1039/c8cc04323j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We employ a linear linker molecule consisting of a benzene functionalised with two tetrazole moieties at para positions. Its self-assembly and coordination with the native silver adatoms and codeposited Fe adatoms on a Ag(111) surface under ultra high vacuum conditions are investigated by means of scanning tunnelling microscopy and X-ray photoelectron spectroscopy. We discover a rich spectrum of room-temperature stable Ag and Fe2+ coordination nodes depending on the formation temperature.
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Affiliation(s)
- Peter Knecht
- Physics Department E20, Technical University of Munich, D-85748 Garching, Germany.
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12
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Kipgen L, Bernien M, Ossinger S, Nickel F, Britton AJ, Arruda LM, Naggert H, Luo C, Lotze C, Ryll H, Radu F, Schierle E, Weschke E, Tuczek F, Kuch W. Evolution of cooperativity in the spin transition of an iron(II) complex on a graphite surface. Nat Commun 2018; 9:2984. [PMID: 30061654 PMCID: PMC6065309 DOI: 10.1038/s41467-018-05399-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 07/05/2018] [Indexed: 11/09/2022] Open
Abstract
Cooperative effects determine the spin-state bistability of spin-crossover molecules (SCMs). Herein, the ultimate scale limit at which cooperative spin switching becomes effective is investigated in a complex [Fe(H2B(pz)2)2(bipy)] deposited on a highly oriented pyrolytic graphite surface, using x-ray absorption spectroscopy. This system exhibits a complete thermal- and light-induced spin transition at thicknesses ranging from submonolayers to multilayers. On increasing the coverage from 0.35(4) to 10(1) monolayers, the width of the temperature-induced spin transition curve narrows significantly, evidencing the buildup of cooperative effects. While the molecules at the submonolayers exhibit an apparent anticooperative behavior, the multilayers starting from a double-layer exhibit a distinctly cooperative spin switching, with a free-molecule-like behavior indicated at around a monolayer. These observations will serve as useful guidelines in designing SCM-based devices.
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Affiliation(s)
- Lalminthang Kipgen
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
| | - Matthias Bernien
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Sascha Ossinger
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118, Kiel, Germany
| | - Fabian Nickel
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Andrew J Britton
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Lucas M Arruda
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Holger Naggert
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118, Kiel, Germany
| | - Chen Luo
- Institut für Experimentelle and Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
| | - Christian Lotze
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Hanjo Ryll
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Florin Radu
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Enrico Schierle
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Eugen Weschke
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Felix Tuczek
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118, Kiel, Germany
| | - Wolfgang Kuch
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
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13
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Vela S, Paulsen H. Cooperativity in Spin Crossover Systems. An Atomistic Perspective on the Devil's Staircase. Inorg Chem 2018; 57:9478-9488. [PMID: 30040398 DOI: 10.1021/acs.inorgchem.8b01463] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cooperativity is key in defining the shape (i.e., gradual, abrupt, or hysteretic) of thermally driven spin transitions in magnetic switches. Despite its importance, there is very little information on its atomistic origin, which hinders the rational design of materials displaying a bistability region (i.e., hysteresis). In this paper, we investigate the spin transition of two solvatomorphs of [Fe(2-pic)3]Cl2, an Fe(II)-complex displaying thermal spin crossover (SCO) from a low-spin (LS) to a high-spin (HS) state with either gradual or abrupt two-step character. To do it, we apply a novel computational protocol to study the cooperativity of SCO compounds from DFT calculations, which does not rely on a priori assumptions on the studied system. The distinct shape of the spin transition is successfully captured, and the atomistic origin of cooperativity is traced back to geometrical distortions of the Fe-N6 core in case of the solvatomorph exhibiting an abrupt transition. According to our calculations, HS and LS molecules contribute differently to cooperativity, which results in a complex energetic evolution of the spin transition that cannot be described by the common Slichter-Drickamer model. The present work opens new avenues for the study of cooperativity of SCO systems having a chemically oriented perspective and demonstrates that quantum chemistry calculations can discriminate the shape of a spin transition, while providing insight into the atomistic underlying factors that contribute to its cooperative behavior.
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Affiliation(s)
- Sergi Vela
- Laboratoire de Chimie Quantique, UMR 7111 , CNRS-Université de Strasbourg , 4 rue Blaise Pascal , F-67000 Strasbourg , France
| | - Hauke Paulsen
- Institut für Physik , Universität zu Lübeck , Ratzeburger Allee 160 , D-23562 Lübeck , Germany
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14
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Kumar KS, Studniarek M, Heinrich B, Arabski J, Schmerber G, Bowen M, Boukari S, Beaurepaire E, Dreiser J, Ruben M. Engineering On-Surface Spin Crossover: Spin-State Switching in a Self-Assembled Film of Vacuum-Sublimable Functional Molecule. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1705416. [PMID: 29356142 DOI: 10.1002/adma.201705416] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/12/2017] [Indexed: 06/07/2023]
Abstract
The realization of spin-crossover (SCO)-based applications requires study of the spin-state switching characteristics of SCO complex molecules within nanostructured environments, especially on surfaces. Except for a very few cases, the SCO of a surface-bound thin molecular film is either quenched or heavily altered due to: (i) molecule-surface interactions and (ii) differing intermolecular interactions in films relative to the bulk. By fabricating SCO complexes on a weakly interacting surface, the interfacial quenching problem is tackled. However, engineering intermolecular interactions in thin SCO active films is rather difficult. Here, a molecular self-assembly strategy is proposed to fabricate thin spin-switchable surface-bound films with programmable intermolecular interactions. Molecular engineering of the parent complex system [Fe(H2 B(pz)2 )2 (bpy)] (pz = pyrazole, bpy = 2,2'-bipyridine) with a dodecyl (C12 ) alkyl chain yields a classical amphiphile-like functional and vacuum-sublimable charge-neutral FeII complex, [Fe(H2 B(pz)2 )2 (C12 -bpy)] (C12 -bpy = dodecyl[2,2'-bipyridine]-5-carboxylate). Both the bulk powder and 10 nm thin films sublimed onto either quartz glass or SiOx surfaces of the complex show comparable spin-state switching characteristics mediated by similar lamellar bilayer like self-assembly/molecular interactions. This unprecedented observation augurs well for the development of SCO-based applications, especially in molecular spintronics.
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Affiliation(s)
- Kuppusamy Senthil Kumar
- Institut de Physique et Chimie des Matériaux (IPCMS), Université de Strasbourg, F-67034, Strasbourg, France
| | - Michał Studniarek
- Institut de Physique et Chimie des Matériaux (IPCMS), Université de Strasbourg, F-67034, Strasbourg, France
- Swiss Light Source, Paul Scherrer Institut (PSI), CH-5232, Villigen, Switzerland
| | - Benoît Heinrich
- Institut de Physique et Chimie des Matériaux (IPCMS), Université de Strasbourg, F-67034, Strasbourg, France
| | - Jacek Arabski
- Institut de Physique et Chimie des Matériaux (IPCMS), Université de Strasbourg, F-67034, Strasbourg, France
| | - Guy Schmerber
- Institut de Physique et Chimie des Matériaux (IPCMS), Université de Strasbourg, F-67034, Strasbourg, France
| | - Martin Bowen
- Institut de Physique et Chimie des Matériaux (IPCMS), Université de Strasbourg, F-67034, Strasbourg, France
| | - Samy Boukari
- Institut de Physique et Chimie des Matériaux (IPCMS), Université de Strasbourg, F-67034, Strasbourg, France
| | - Eric Beaurepaire
- Institut de Physique et Chimie des Matériaux (IPCMS), Université de Strasbourg, F-67034, Strasbourg, France
| | - Jan Dreiser
- Swiss Light Source, Paul Scherrer Institut (PSI), CH-5232, Villigen, Switzerland
| | - Mario Ruben
- Institut de Physique et Chimie des Matériaux (IPCMS), Université de Strasbourg, F-67034, Strasbourg, France
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344, Eggenstein-Leopoldshafen, Germany
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15
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Janet JP, Chan L, Kulik HJ. Accelerating Chemical Discovery with Machine Learning: Simulated Evolution of Spin Crossover Complexes with an Artificial Neural Network. J Phys Chem Lett 2018; 9:1064-1071. [PMID: 29425453 DOI: 10.1021/acs.jpclett.8b00170] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Machine learning (ML) has emerged as a powerful complement to simulation for materials discovery by reducing time for evaluation of energies and properties at accuracy competitive with first-principles methods. We use genetic algorithm (GA) optimization to discover unconventional spin-crossover complexes in combination with efficient scoring from an artificial neural network (ANN) that predicts spin-state splitting of inorganic complexes. We explore a compound space of over 5600 candidate materials derived from eight metal/oxidation state combinations and a 32-ligand pool. We introduce a strategy for error-aware ML-driven discovery by limiting how far the GA travels away from the nearest ANN training points while maximizing property (i.e., spin-splitting) fitness, leading to discovery of 80% of the leads from full chemical space enumeration. Over a 51-complex subset, average unsigned errors (4.5 kcal/mol) are close to the ANN's baseline 3 kcal/mol error. By obtaining leads from the trained ANN within seconds rather than days from a DFT-driven GA, this strategy demonstrates the power of ML for accelerating inorganic material discovery.
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Affiliation(s)
- Jon Paul Janet
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Lydia Chan
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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