1
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Srivastava G, Štacko P, Mendieta-Moreno JI, Edalatmanesh S, Kistemaker JCM, Heideman GH, Zoppi L, Parschau M, Feringa BL, Ernst KH. Driving a Third Generation Molecular Motor with Electrons Across a Surface. ACS NANO 2023; 17:3931-3938. [PMID: 36794964 DOI: 10.1021/acsnano.2c12340] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Excitation of single molecules with electrons tunneling between a sharp metallic tip of a scanning tunneling microscope and a metal surface is one way to study and control dynamics of molecules on surfaces. Electron tunneling induced dynamics may lead to hopping, rotation, molecular switching, or chemical reactions. Molecular motors that convert rotation of subgroups into lateral movement on a surface can in principle also be driven by tunneling electrons. For such surface-bound motor molecules the efficiency of motor action with respect to electron dose is still not known. Here, the response of a molecular motor containing two rotor units in the form of overcrowded alkene groups to inelastic electron tunneling has been examined on a Cu(111) surface in ultrahigh vacuum at 5 K. Upon vibrational excitation, switching between different molecular conformations is observed, including conversion of enantiomeric states of chiral conformations. Tunneling at energies in the range of electronic excitations causes activation of motor action and movement across the surface. The expected unidirectional rotation of the two rotor units causes forward movements but with a low degree of translational directionality.
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Affiliation(s)
- Gitika Srivastava
- Molecular Surface Science and Coating Technology Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Peter Štacko
- Centre for Systems Chemistry, Stratingh Institute for Chemistry and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Jesús I Mendieta-Moreno
- Nanosurf Laboratory, Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
| | - Shayan Edalatmanesh
- Nanosurf Laboratory, Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
| | - Jos C M Kistemaker
- Centre for Systems Chemistry, Stratingh Institute for Chemistry and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - G Henrieke Heideman
- Centre for Systems Chemistry, Stratingh Institute for Chemistry and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Laura Zoppi
- Molecular Surface Science and Coating Technology Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Manfred Parschau
- Molecular Surface Science and Coating Technology Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Ben L Feringa
- Centre for Systems Chemistry, Stratingh Institute for Chemistry and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Karl-Heinz Ernst
- Molecular Surface Science and Coating Technology Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
- Nanosurf Laboratory, Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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2
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Kempfer-Robertson EM, Avdic I, Haase MN, Pike TD, Thompson LM. Protonation state control of electric field induced molecular switching mechanisms. Phys Chem Chem Phys 2023; 25:5251-5261. [PMID: 36723228 DOI: 10.1039/d2cp04494c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Scanning tunneling microscopy tip-induced deprotonation has been demonstrated experimentally and can be used as an additional control mechanism in electric-field induced molecular switching. The goal of the current work is to establish whether (de)protonation can be used to inhibit or enhance the electric field controlled thermal and photoisomerization processes. Dihydroxyazobenzene is used as a model system, where protonation/deprotonation of the free hydroxyl moiety changes the azo bond order, and so modifies the rate of electric field induced isomerization. Through the combined action of deprotonation and applied field, it was found that the cis-to-trans thermal isomerization barrier could be completely removed, changing the isomerization half-life from the order of several months. In addition, due to the presence of multiple isomerization mechanisms, electric fields could modify the isomerization kinetics by increasing the number of energetically viable isomerization pathways, rather than reducing the activation barrier of the lowest energy pathway. Excited state calculations indicated that the protonation state and electric field could be used together to control the presence of electronic degeneracies along the rotation pathway between S0/S1, and along all three pathways between S1/S2. This work provides insight into the mechanisms that enable the use of protonation state, light, and electric fields in concert to control molecular switches.
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Affiliation(s)
| | - Irma Avdic
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40208, USA.
| | - Meagan N Haase
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40208, USA.
| | - Thomas Dane Pike
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40208, USA.
| | - Lee M Thompson
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40208, USA.
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3
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Yang YJ, Li SX, Chen DL, Long ZW. Geometric Structure, Electronic, and Spectral Properties of Metal-free Phthalocyanine under the External Electric Fields. ACS OMEGA 2022; 7:41266-41274. [PMID: 36406576 PMCID: PMC9670904 DOI: 10.1021/acsomega.2c04941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Here, the ground-state structures, electronic structures, polarizability, and spectral properties of metal-free phthalocyanine (H2Pc) under different external electric fields (EEFs) are investigated. The results show that EEF has an ultrastrong regulation effect on various aspects of H2Pc; the geometric structures, electronic properties, polarizability, and spectral properties are strongly sensitive to the EEF. In particular, an EEF of 0.025 a.u. is an important control point: an EEF of 0.025 a.u. will bend the benzene ring subunits to the positive and negative x directions of the planar molecule. Flipping the EEF from positive (0.025 a.u.) to negative (-0.025 a.u.) flips also the bending direction of benzene ring subunits. The H2Pc shows different dipole moments projecting an opposite direction along the x direction (-84 and 84 Debye for EEFs of -0.025 and 0.025 a.u., respectively) under negative and positive EEF, revealing a significant dipole moment transformation. Furthermore, when the EEF is removed, the molecule can be restored to the planar structure. The transformation of the H2Pc structure can be induced by the EEF, which has potential applications in the molecular devices such as molecular switches or molecular forceps. EEF lowers total energy and reduces highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap; especially, an EEF of 0.025 a.u. can reduce the HOMO-LUMO gap from 2.1 eV (in the absence of EEF) to 0.37 eV, and thus, it can enhance the molecular conductivity. The first hyperpolarizability of H2Pc is 0 in the absence of EEF; remarkably, an EEF of 0.025 a.u. can enhance the first hyperpolarizability up to 15,578 a.u. Therefore, H2Pc under the EEF could be introduced as a promising innovative nonlinear optical (NLO) nanomaterial such as NLO switches. The strong EEF (0.025 a.u.) causes a large number of new absorption peaks in IR and Raman spectra and causes the redshift of electronic absorption spectra. The changes of EEF can be used to regulate the structure transformation and properties of H2Pc, which can promote the application of H2Pc in nanometer fields such as molecular devices.
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Affiliation(s)
- Yue-Ju Yang
- School
of Physics and Electronic Science, Guizhou
Education University, Guiyang 550018, China
| | - Shi-Xiong Li
- School
of Physics and Electronic Science, Guizhou
Education University, Guiyang 550018, China
| | - De-Liang Chen
- School
of Physics and Electronic Science, Guizhou
Education University, Guiyang 550018, China
| | - Zheng-Wen Long
- College
of Physics, Guizhou University, Guiyang 550025, China
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4
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Avdic I, Kempfer-Robertson EM, Thompson LM. Oriented External Electric Field Tuning of Unsubstituted Azoheteroarene Thermal Isomerization Half-Lives. J Phys Chem A 2021; 125:8238-8248. [PMID: 34494847 DOI: 10.1021/acs.jpca.1c06102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Azoheteroarenes are relatively new photoswitchable compounds, where one of the phenyl rings of an azobenzene molecule is replaced by a heteroaromatic five-membered ring. Recent findings on methylated azoheteroarenes show that these photoswitches have potential in various optically addressable applications. The thermal stability of molecular switches is one of the primary factors considered in the design process. For molecular memory or energy storage devices, long thermal relaxation times are required. However, inducing a short thermal isomerization lifetime is required to release stored energy or as an alternative to photoswitching to avoid overlapping absorption spectra that reduce switching fidelity. In this study, we investigate how oriented external electric fields can be used to tune the thermal isomerization properties of three unsubstituted heteroaryl azo compounds-azoimidazole, azopyrazole, and azopyrrole. We show that favorable electric field orientations can increase the thermal half-life of studied molecules by as much as 60 times or reduce it from tens of days to seconds, compared to their half-life values in the field-free environment. A deeper understanding of the relationship between structure and kinetic properties provides insight as to how molecular switches can be designed for their electric field response in switching applications.
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Affiliation(s)
- Irma Avdic
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40208, United States
| | | | - Lee M Thompson
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40208, United States
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5
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Sršeň Š, Sita J, Slavíček P, Ladányi V, Heger D. Limits of the Nuclear Ensemble Method for Electronic Spectra Simulations: Temperature Dependence of the (E)-Azobenzene Spectrum. J Chem Theory Comput 2020; 16:6428-6438. [DOI: 10.1021/acs.jctc.0c00579] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Štěpán Sršeň
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic
| | - Jaroslav Sita
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic
| | - Petr Slavíček
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic
| | - Vít Ladányi
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
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6
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Xie Z, Duan S, Wang CK, Luo Y. Finding the true pathway for reversible isomerization of a single azobenzene molecule tumbling on Au(111) surface. NANOSCALE 2020; 12:10474-10479. [PMID: 32373867 DOI: 10.1039/d0nr01629b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Switchable trans-cis isomerization of azobenzene (AB) and its derivatives on metallic surfaces have offered rich possibilities to functionalize molecular devices. However, the lack of a good understanding of the isomerization pathway has severely limited our ability for rational design. One of the long-debated issues is the cis configuration of the parental AB on the Au(111) surface, for which the experimentally inferred structure differs from the theoretically predicted global minimum. Here, we theoretically identify a new in situ metastable configuration for cis-AB on Au(111) that can reproduce all the observations reported in the scanning tunneling microscopy experiments. It reveals that the bistability of AB on the Au(111) surface is attributed to the significantly increased kinetic stability of the newly discovered cis-AB isomer. A fascinating tumbling pathway that overcomes two energy barriers stimulated by tunneling electrons for the trans-cis AB isomerization on Au(111) has been verified, suggesting a new type of molecular motion based on the AB systems.
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Affiliation(s)
- Zhen Xie
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, Jinan 250014, People's Republic of China
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7
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Kempfer-Robertson EM, Thompson LM. Effect of Oriented External Electric Fields on the Photo and Thermal Isomerization of Azobenzene. J Phys Chem A 2020; 124:3520-3529. [PMID: 32286821 DOI: 10.1021/acs.jpca.0c00492] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Azobenzene is a prototype molecule with potential applications in molecular switches, solar thermal batteries, sensors, photoresponsive membranes, molecular electronics, data storage, and nonlinear optics. Photo and thermal isomerization pathways exhibit different charge-transfer character and dipole moments, implying that the use of electric fields can be used to modulate the reactivity of azobenzene. This article examines the differential effect of orientated electric fields on the rotation and inversion thermal and photoisomerization pathways of azobenzene to explore the feasibility of using electric fields in the design of azobenzene-based molecular devices. Our findings demonstrate that the application of orientated electric fields modifies the accessibility of the S0/S1 seam of electronic degeneracy, as well as changes the energetically favored relaxation pathway in the branching space to yield different photoproducts. In addition, we observed strong-field dipole-inversion effects that cause a topographical change in the response of the potential energy surface to the applied field and can result in geometric minima that do not exist under field-free conditions. On the S0 surface, transition barriers can be modified on the order of ±10 kcal mol-1, enabling control of thermal isomerization rates.
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Affiliation(s)
| | - Lee M Thompson
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40205, United States
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8
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Benjalal Y, Bonvoisin J, Bouju X. Unraveling the molecular conformations of a single ruthenium complex adsorbed on the Ag(111) surface by calculations. Phys Chem Chem Phys 2019; 21:10022-10027. [PMID: 31041976 DOI: 10.1039/c9cp01244c] [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 tris(dibenzoylmethanato)ruthenium (Ru(dbm)3) molecule has recently been characterized by scanning tunneling microscopy (STM) experiments upon adsorption on Ag(111). The adsorbed Ru(dbm)3 molecule shows two conformations with respect to the [11[combining macron]0] direction of the substrate, one with a three-lobed feature and the other one with a bi-lobed structure. For each of these structures, the molecule can take two geometries (states). Molecular mechanics calculations in a semi-empirical framework and STM calculated images reveal that these states on the substrate originate from the enantiomer of the Ru(dbm)3 molecule in the case of three-lobed structure and from the rotation of the two phenyls in the top dbm moities for the bi-lobed form.
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Affiliation(s)
- Youness Benjalal
- Université Sultan Moulay Slimane, Faculté polydisciplinaire, Département de chimie, Béni Mellal, Morocco.
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9
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Martins GF, Cabral BJC. Electron Propagator Theory Approach to the Electron Binding Energies of a Prototypical Photo-Switch Molecular System: Azobenzene. J Phys Chem A 2019; 123:2091-2099. [PMID: 30779578 DOI: 10.1021/acs.jpca.9b00532] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electron binding energies for the trans and cis conformers of azobenzene (AB), a prototypical photoswitch, were investigated by electron propagator theory (EPT). The EPT results are compared with data from photoelectron and electron transmission spectroscopies and complemented by the calculation of the differences between vertical and adiabatic ionization energies and electron affinities of the AB conformers. These differences are discussed in terms of the geometry changes associated with the processes of ionization and electron attachment. The results pointed out a major difference between these processes when we compare trans-AB and cis-AB. For trans-AB, electron attachment leads to a small geometry change, whereas for cis-AB, it is the ionized structure that keeps some similarity with the neutral species. We emphasize the interest of the present results for a better understanding of recent experiments on the dark cis-trans isomerization in different environments, specifically for azobenzenes in interaction with gold nanoparticles, where the proposed cis-trans isomerization mechanism relies on electron transfer induced isomerization.
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Affiliation(s)
- Gabriel F Martins
- Biosystems and Integrative Sciences Institute (BioISI) , Faculdade de Ciências, Universidade de Lisboa , 1749-016 Lisboa , Portugal
| | - Benedito J C Cabral
- Biosystems and Integrative Sciences Institute (BioISI) , Faculdade de Ciências, Universidade de Lisboa , 1749-016 Lisboa , Portugal.,Departamento de Quı́mica e Bioquı́mica , Faculdade de Ciências, Universidade de Lisboa , 1749-016 Lisboa , Portugal
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10
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Effect of acceptor moieties on static and dynamic first hyperpolarizability of azobenzene chromophores. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2018.12.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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11
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Maurer RJ, Reuter K. Computational design of metal-supported molecular switches: transient ion formation during light- and electron-induced isomerisation of azobenzene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:044003. [PMID: 30523934 DOI: 10.1088/1361-648x/aaf0e1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In molecular nanotechnology, a single molecule is envisioned to act as the basic building block of electronic devices. Such devices may be of special interest for organic photovoltaics, data storage, and smart materials. However, more often than not the molecular function is quenched upon contact with a conducting support. Trial-and-error-based decoupling strategies via molecular functionalisation and change of substrate have in many instances proven to yield unpredictable results. The adsorbate-substrate interactions that govern the function can be understood with the help of first-principles simulation. Employing dispersion-corrected density-functional theory (DFT) and linear expansion delta-self-consistent-field DFT, the electronic structure of a prototypical surface-adsorbed functional molecule, namely azobenzene adsorbed to (1 1 1) single crystal facets of copper, silver and gold, is investigated and the main reasons for the loss or survival of the switching function upon adsorption are identified. The light-induced switching ability of a functionalised derivative of azobenzene on Au(1 1 1) and azobenzene on Ag(1 1 1) and Au(1 1 1) is assessed based on the excited-state potential energy landscapes of their transient molecular ions, which are believed to be the main intermediates of the experimentally observed isomerisation reaction. We provide a rationalisation of the experimentally observed function or lack thereof that connects to the underlying chemistry of the metal-surface interaction and provides insights into general design strategies for complex light-driven reactions at metal surfaces.
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Affiliation(s)
- Reinhard J Maurer
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, United Kingdom
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12
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Ehlert C, Gühr M, Saalfrank P. An efficient first principles method for molecular pump-probe NEXAFS spectra: Application to thymine and azobenzene. J Chem Phys 2018; 149:144112. [DOI: 10.1063/1.5050488] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Christopher Ehlert
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave. W, Waterloo, Ontario N2L3C5, Canada
| | - Markus Gühr
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam-Golm, Germany
| | - Peter Saalfrank
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam-Golm, Germany
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13
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Vasilyev IV, Fominykh OD, Balakina MY. Dynamic first hyperpolarizability of trans- and cis-isomers of azobenzene chromophore DO3 calculated at DFT and MP2 levels. COMPUT THEOR CHEM 2018. [DOI: 10.1016/j.comptc.2018.06.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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14
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Muždalo A, Saalfrank P, Vreede J, Santer M. Cis-to-Trans Isomerization of Azobenzene Derivatives Studied with Transition Path Sampling and Quantum Mechanical/Molecular Mechanical Molecular Dynamics. J Chem Theory Comput 2018; 14:2042-2051. [DOI: 10.1021/acs.jctc.7b01120] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Anja Muždalo
- Department of Theory and Biosystems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Peter Saalfrank
- Department of Chemistry, University of Potsdam, 14476 Potsdam, Germany
| | - Jocelyne Vreede
- Computational Chemistry, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Mark Santer
- Department of Theory and Biosystems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
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15
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Rietze C, Titov E, Lindner S, Saalfrank P. Thermal isomerization of azobenzenes: on the performance of Eyring transition state theory. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:314002. [PMID: 28557809 DOI: 10.1088/1361-648x/aa75bd] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The thermal [Formula: see text] (back-)isomerization of azobenzenes is a prototypical reaction occurring in molecular switches. It has been studied for decades, yet its kinetics is not fully understood. In this paper, quantum chemical calculations are performed to model the kinetics of an experimental benchmark system, where a modified azobenzene (AzoBiPyB) is embedded in a metal-organic framework (MOF). The molecule can be switched thermally from cis to trans, under solvent-free conditions. We critically test the validity of Eyring transition state theory for this reaction. As previously found for other azobenzenes (albeit in solution), good agreement between theory and experiment emerges for activation energies and activation free energies, already at a comparatively simple level of theory, B3LYP/6-31G* including dispersion corrections. However, theoretical Arrhenius prefactors and activation entropies are in qualitiative disagreement with experiment. Several factors are discussed that may have an influence on activation entropies, among them dynamical and geometric constraints (imposed by the MOF). For a simpler model-[Formula: see text] isomerization in azobenzene-a systematic test of quantum chemical methods from both density functional theory and wavefunction theory is carried out in the context of Eyring theory. Also, the effect of anharmonicities on activation entropies is discussed for this model system. Our work highlights capabilities and shortcomings of Eyring transition state theory and quantum chemical methods, when applied for the [Formula: see text] (back-)isomerization of azobenzenes under solvent-free conditions.
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Affiliation(s)
- Clemens Rietze
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany
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16
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Reecht G, Lotze C, Sysoiev D, Huhn T, Franke KJ. Disentangling electron- and electric-field-induced ring-closing reactions in a diarylethene derivative on Ag(1 1 1). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:294001. [PMID: 28557794 DOI: 10.1088/1361-648x/aa75c1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Using scanning tunneling microscopy and spectroscopy we investigate the adsorption properties and ring-closing reaction of a diarylethene derivative (C5F-4Py) on a Ag(1 1 1) surface. We identify an electron-induced reaction mechanism, with a quantum yield varying from 10-14-10-9 per electron upon variation of the bias voltage from 1-2 V. We ascribe the drastic increase in switching efficiency to a resonant enhancement upon tunneling through molecular orbitals. Additionally, we resolve the ring-closing reaction even in the absence of a current passing through the molecule. In this case the electric-field can modify the reaction barrier, leading to a finite switching probability at 4.8 K. A detailed analysis of the switching events shows that a simple plate-capacitor model for the tip-surface junction is insufficient to explain the distance dependence of the switching voltage. Instead, describing the tip as a sphere is in agreement with the findings. We resolve small differences in the adsorption configuration of the closed isomer, when comparing the electron- and field-induced switching product.
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Affiliation(s)
- Gaël Reecht
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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17
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Malyar IV, Titov E, Lomadze N, Saalfrank P, Santer S. Photoswitching of azobenzene-containing self-assembled monolayers as a tool for control over silicon surface electronic properties. J Chem Phys 2017; 146:104703. [DOI: 10.1063/1.4978225] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ivan V. Malyar
- Department of Nano- and Biomedical Technologies, Saratov State University, Astrakhanskaya 83, 410012 Saratov, Russia
| | - Evgenii Titov
- Experimental Physics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
- Theoretical Chemistry, Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Nino Lomadze
- Experimental Physics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Peter Saalfrank
- Theoretical Chemistry, Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Svetlana Santer
- Experimental Physics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
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18
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Novko D, Blanco-Rey M, Tremblay JC. Intermode Coupling Drives the Irreversible Tautomerization in Porphycene on Copper(111) Induced by Scanning Tunnelling Microscopy. J Phys Chem Lett 2017; 8:1053-1059. [PMID: 28198627 DOI: 10.1021/acs.jpclett.7b00141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this contribution, we develop a nonadiabatic theory that explains, from first-principles, the recently reported irreversible trans → cis tautomerization of porphycene on Cu(111) induced by a scanning tunnelling microscope at finite bias. The inelastic contribution to the STM current is found to excite a large number of skeletal vibrational modes of the molecule, thereby inducing a deformation of the potential energy landscape along the hydrogen transfer coordinate. Above a threshold bias, the stability of the tautomers is reversed, which indirectly drives the reaction via intermode coupling. The proposed potential deformation term accounts effectively for the excitation of all internal vibrational modes without increasing the dimensionality of the problem. The model yields information about reaction rates, explains the reaction irreversibility at low temperatures, and accounts for the presence of resonant processes.
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Affiliation(s)
- Dino Novko
- Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
| | - María Blanco-Rey
- Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
- Departamento de Fı́sica de Materiales, Facultad de Quı́micas UPV/EHU , Apartado 1072, 20018 Donostia-San Sebastián, Spain
| | - Jean Christophe Tremblay
- Institut für Chemie und Biochemie, Freie Universität Berlin , Takustrasse 3, 14195 Berlin, Germany
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Böckmann H, Liu S, Mielke J, Gawinkowski S, Waluk J, Grill L, Wolf M, Kumagai T. Direct Observation of Photoinduced Tautomerization in Single Molecules at a Metal Surface. NANO LETTERS 2016; 16:1034-41. [PMID: 26796945 DOI: 10.1021/acs.nanolett.5b04092] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Molecular switches are of fundamental importance in nature, and light is an important stimulus to selectively drive the switching process. However, the local dynamics of a conformational change in these molecules remain far from being completely understood at the single-molecule level. Here, we report the direct observation of photoinduced tautomerization in single porphycene molecules on a Cu(111) surface by using a combination of low-temperature scanning tunneling microscopy and laser excitation in the near-infrared to ultraviolet regime. It is found that the thermodynamically stable trans configuration of porphycene can be converted to the metastable cis configuration in a unidirectional fashion by photoirradiation. The wavelength dependence of the tautomerization cross section exhibits a steep increase around 2 eV and demonstrates that excitation of the Cu d-band electrons and the resulting hot carriers play a dominant role in the photochemical process. Additionally, a pronounced isotope effect in the cross section (∼100) is observed when the transferred hydrogen atoms are substituted with deuterium, indicating a significant contribution of zero-point energy in the reaction. Combined with the study of inelastic tunneling electron-induced tautomerization with the STM, we propose that tautomerization occurs via excitation of molecular vibrations after photoexcitation. Interestingly, the observed cross section of ∼10(-19) cm(2) in the visible-ultraviolet region is much higher than that of previously studied molecular switches on a metal surface, for example, azobenzene derivatives (10(-23)-10(-22) cm(2)). Furthermore, we examined a local environmental impact on the photoinduced tautomerization by varying molecular density on the surface and find substantial changes in the cross section and quenching of the process due to the intermolecular interaction at high density.
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Affiliation(s)
- H Böckmann
- Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society , Faradayweg 4-6, 14195 Berlin, Germany
| | - S Liu
- Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society , Faradayweg 4-6, 14195 Berlin, Germany
| | - J Mielke
- Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society , Faradayweg 4-6, 14195 Berlin, Germany
| | - S Gawinkowski
- Institute of Physical Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, Warsaw 01-224, Poland
| | - J Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, Warsaw 01-224, Poland
- Faculty of Mathematics and Natural Sciences, College of Science, Cardinal Stefan Wyszyński University , Dewajtis 5, 01-815 Warsaw, Poland
| | - L Grill
- Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society , Faradayweg 4-6, 14195 Berlin, Germany
- Department of Physical Chemistry, University of Graz , Heinrichstrasse 28, 8010 Graz, Austria
| | - M Wolf
- Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society , Faradayweg 4-6, 14195 Berlin, Germany
| | - T Kumagai
- Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society , Faradayweg 4-6, 14195 Berlin, Germany
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Ladenthin JN, Grill L, Gawinkowski S, Liu S, Waluk J, Kumagai T. Hot Carrier-Induced Tautomerization within a Single Porphycene Molecule on Cu(111). ACS NANO 2015; 9:7287-7295. [PMID: 26057840 DOI: 10.1021/acsnano.5b02147] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Here, we report the study of tautomerization within a single porphycene molecule adsorbed on a Cu(111) surface using low-temperature scanning tunneling microscopy (STM) at 5 K. While molecules are adsorbed on the surface exclusively in the thermodynamically stable trans tautomer after deposition, a voltage pulse from the STM can induce the unidirectional trans → cis and reversible cis ↔ cis tautomerization. From the voltage and current dependence of the tautomerization yield (rate), it is revealed that the process is induced by vibrational excitation via inelastic electron tunneling. However, the metastable cis molecules are thermally switched back to the trans tautomer by heating the surface up to 30 K. Furthermore, we have found that the unidirectional tautomerization can be remotely controlled at a distance from the STM tip. By analyzing the nonlocal process in dependence on various experimental parameters, a hot carrier-mediated mechanism is identified, in which hot electrons (holes) generated by the STM travel along the surface and induce the tautomerization through inelastic scattering with a molecule. The bias voltage and coverage dependent rate of the nonlocal tautomerization clearly show a significant contribution of the Cu(111) surface state to the hot carrier-induced process.
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Affiliation(s)
- Janina N Ladenthin
- †Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Leonhard Grill
- †Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
- ‡Department of Physical Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Sylwester Gawinkowski
- §Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland
| | - Shuyi Liu
- †Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Jacek Waluk
- §Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland
| | - Takashi Kumagai
- †Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
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Li M, den Boer D, Iavicoli P, Adisoejoso J, Uji-i H, Van der Auweraer M, Amabilino DB, Elemans JAAW, De Feyter S. Tip-Induced Chemical Manipulation of Metal Porphyrins at a Liquid/Solid Interface. J Am Chem Soc 2014; 136:17418-21. [DOI: 10.1021/ja510930z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Min Li
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
- CAS
Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety,
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Duncan den Boer
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
- Institute
for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg
135, 6525 AJ Nijmegen, The Netherlands
| | - Patrizia Iavicoli
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC), Universitat Autónoma de Barcelona, Campus Universitari, 08193 Bellaterra, Catalonia, Spain
| | - Jinne Adisoejoso
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
| | - Hiroshi Uji-i
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
| | - Mark Van der Auweraer
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
| | - David B. Amabilino
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC), Universitat Autónoma de Barcelona, Campus Universitari, 08193 Bellaterra, Catalonia, Spain
| | - Johannes A. A. W. Elemans
- Institute
for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg
135, 6525 AJ Nijmegen, The Netherlands
| | - Steven De Feyter
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
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Schulze M, Bronner C, Tegeder P. Adsorption energetics of azobenzenes on noble metal surfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:355004. [PMID: 25077738 DOI: 10.1088/0953-8984/26/35/355004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Temperature-programmed desorption measurements have been applied to investigate the binding energies of four systems, namely the photochromic molecular compounds azobenzene and tetra-tert-butyl-azobenzene (TBA) adsorbed on the Au(1 1 1) and Ag(1 1 1) surfaces, respectively. The binding energy is a measure of the interaction strength between substrate and adsorbate. It therefore provides a suitable means for an investigation of the decoupling strategy pursued by adding the tert-butyl spacer groups and choosing the more inert gold substrate, which leads to TBA/Au(1 1 1), the only photoisomerizable system out of the four. Ironically, we find TBA/Au(1 1 1) to be the most strongly bound. The binding of TBA to Au(1 1 1) is almost 0.4 eV stronger than to Ag(1 1 1). On the other hand, azobenzene binds approximately equally strongly to both surfaces. These findings are consistent with and provide support for the recently proposed hybridization between the HOMO of TBA and the Au(1 1 1) d-band needed for the hole attachment which induces the isomerization.
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Affiliation(s)
- Michael Schulze
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany. Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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23
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Harabuchi Y, Ishii M, Nakayama A, Noro T, Taketsugu T. A multireference perturbation study of the NN stretching frequency of trans-azobenzene in nπ* excitation and an implication for the photoisomerization mechanism. J Chem Phys 2013; 138:064305. [DOI: 10.1063/1.4790611] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Thies S, Sell H, Bornholdt C, Schütt C, Köhler F, Tuczek F, Herges R. Light-driven coordination-induced spin-state switching: rational design of photodissociable ligands. Chemistry 2012; 18:16358-68. [PMID: 23090862 DOI: 10.1002/chem.201201698] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 08/29/2012] [Indexed: 11/10/2022]
Abstract
The bistability of spin states (e.g., spin crossover) in bulk materials is well investigated and understood. We recently extended spin-state switching to isolated molecules at room temperature (light-driven coordination-induced spin-state switching, or LD-CISSS). Whereas bistability and hysteresis in conventional spin-crossover materials are caused by cooperative effects in the crystal lattice, spin switching in LD-CISSS is achieved by reversibly changing the coordination number of a metal complex by means of a photochromic ligand that binds in one configuration but dissociates in the other form. We present mathematical proof that the maximum efficiency in property switching by such a photodissociable ligand (PDL) is only dependent on the ratio of the association constants of both configurations. Rational design by using DFT calculations was applied to develop a photoswitchable ligand with a high switching efficiency. The starting point was a nickel-porphyrin as the transition-metal complex and 3-phenylazopyridine as the photodissociable ligand. Calculations and experiments were performed in two iterative steps to find a substitution pattern at the phenylazopyridine ligand that provided optimum performance. Following this strategy, we synthesized an improved photodissociable ligand that binds to the Ni-porphyrin with an association constant that is 5.36 times higher in its trans form than in the cis form. The switching efficiency between the diamagnetic and paramagnetic state is efficient as well (72% paramagnetic Ni-porphyrin after irradiation at 365 nm, 32% paramagnetic species after irradiation at 440 nm). Potential applications arise from the fact that the LD-CISSS approach for the first time allows reversible switching of the magnetic susceptibility of a homogeneous solution. Photoswitchable contrast agents for magnetic resonance imaging and light-controlled magnetic levitation are conceivable applications.
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Affiliation(s)
- Steffen Thies
- Institut für Organische Chemie, Universität Kiel, Otto-Hahn-Platz 4, 24118 Kiel, Germany
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25
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Tegeder P. Optically and thermally induced molecular switching processes at metal surfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:394001. [PMID: 22964773 DOI: 10.1088/0953-8984/24/39/394001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Using light to control the switching of functional properties of surface-bound species is an attractive strategy for the development of new technologies with possible applications in molecular electronics and functional surfaces and interfaces. Molecular switches are promising systems for such a route, since they possess the ability to undergo reversible changes between different molecular states and accordingly molecular properties by excitation with light or other external stimuli. In this review, recent experiments on photo- and thermally induced molecular switching processes at noble metal surfaces utilizing two-photon photoemission and surface vibrational spectroscopies are reported. The investigated molecular switches can either undergo a trans-cis isomerization or a ring opening-closure reaction. Two approaches concerning the connection of the switches to the surface are applied: physisorbed switches, i.e. molecules in direct contact with the substrate, and surface-decoupled switches incorporated in self-assembled monolayers. Elementary processes in molecular switches at surfaces, such as excitation mechanisms in photoisomerization and kinetic parameters for thermally driven reactions, which are essential for a microscopic understanding of molecular switching at surfaces, are presented. This in turn is needed for designing an appropriate adsorbate-substrate system with the desired switchable functionality controlled by external stimuli.
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Affiliation(s)
- Petra Tegeder
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, D-14195 Berlin, Germany.
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26
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Heinemann N, Grunau J, Leißner T, Andreyev O, Kuhn S, Jung U, Zargarani D, Herges R, Magnussen O, Bauer M. Reversible switching in self-assembled monolayers of azobenzene thiolates on Au (111) probed by threshold photoemission. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.03.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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27
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Gopakumar TG, Matino F, Naggert H, Bannwarth A, Tuczek F, Berndt R. Electron-Induced Spin Crossover of Single Molecules in a Bilayer on Gold. Angew Chem Int Ed Engl 2012; 51:6262-6. [DOI: 10.1002/anie.201201203] [Citation(s) in RCA: 228] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Indexed: 11/06/2022]
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28
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Gopakumar TG, Matino F, Naggert H, Bannwarth A, Tuczek F, Berndt R. Elektroneninduzierter Spin-Crossover von Einzelmolekülen in einer Doppellage auf Gold. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201201203] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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29
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Cusati T, Granucci G, Martínez-Núñez E, Martini F, Persico M, Vázquez S. Semiempirical Hamiltonian for simulation of azobenzene photochemistry. J Phys Chem A 2011; 116:98-110. [PMID: 22107348 DOI: 10.1021/jp208574q] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a semiempirical Hamiltonian that provides an accurate description of the first singlet and triplet potential energy surfaces of azobenzene for use in direct simulations of the excited-state dynamics. The parameterization made use of spectroscopic and thermochemical data and the best ab initio results available to date. Two-dimensional potential energy surfaces based on constrained geometry optimizations are presented for the states that are most relevant for the photochemistry of azobenzene, namely, S(0), S(1), and S(2). In order to run simulations of the photodynamics of azobenzene in hydrocarbons or hydroxylic solvents, we determined the interactions of methane and methanol with the azo group by ab initio calculations and fitted the interactions with a QM/MM interaction Hamiltonian.
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Affiliation(s)
- Teresa Cusati
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, v. Risorgimento 35, I-56126 Pisa, Italy
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30
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Maurer RJ, Reuter K. Assessing computationally efficient isomerization dynamics: ΔSCF density-functional theory study of azobenzene molecular switching. J Chem Phys 2011; 135:224303. [DOI: 10.1063/1.3664305] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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31
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Chapman C, Paci I. Behavior of a chemisorbed azobenzene derivative in an STM environment: A DFT study of charged states and electric fields. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.10.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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32
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Utecht M, Klamroth T, Saalfrank P. Optical absorption and excitonic coupling in azobenzenes forming self-assembled monolayers: a study based on density functional theory. Phys Chem Chem Phys 2011; 13:21608-14. [PMID: 22071571 DOI: 10.1039/c1cp22793a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Based on the analysis of optical absorption spectra, it has recently been speculated that the excitonic coupling between individual azobenzene-functionalized alkanethiols arranged in a self-assembled monolayer (SAM) on a gold surface could be strong enough to hinder collective trans-cis isomerization-on top of steric hindrance [Gahl et al., J. Am. Chem. Soc., 2010, 132, 1831]. Using models of SAMs of increasing complexity (dimer, linear N-mers, and two-dimensionally arranged N-mers) and density functional theory on the (TD-) B3LYP/6-31G* level, we determine optical absorption spectra, the nature and magnitude of excitonic couplings, and the corresponding spectral shifts. It is found that at inter-monomer distances of about 20 Å and above, TD-B3LYP excitation frequencies (and signal intensities) can be well described by the frequently used point-dipole approximation. Further, calculated blue shifts in optical absorption spectra account for the experimental observations made for azobenzene/gold SAMs, and hint to the fact that they can indeed be responsible for reduced switching probability in densely packed self-assembled structures.
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Affiliation(s)
- Manuel Utecht
- Universität Potsdam, Institut für Chemie, Karl-Liebknecht-Straße 24-25, D-14476 Potsdam-Golm, Germany
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Abstract
Theoretical predictions of rotational barriers for pi-conjugated substituents of aromatic rings sometimes significantly overestimate the corresponding experimental values. In this work, the rotational barriers in benzaldehyde, azobenzene, and azonaphthalene are studied by DFT calculations employing a variety of exchange-correlation functionals and basis sets. The results for benzaldehyde and azobenzene agree with previously published theoretical values. For azonaphthalene, 10 unique minima and corresponding rotational barriers have been found. The ability to distinguish minima connected by rotational barriers opens an opportunity for a detailed experimental study of rotational barrier heights in substituted aromatics.
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Affiliation(s)
- Rebecca L Klug
- Department of Chemistry, Marshall University, Huntington, West Virginia 25755, USA
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Safiei A, Henzl J, Morgenstern K. Isomerization of an azobenzene derivative on a thin insulating layer by inelastically tunneling electrons. PHYSICAL REVIEW LETTERS 2010; 104:216102. [PMID: 20867119 DOI: 10.1103/physrevlett.104.216102] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Indexed: 05/29/2023]
Abstract
Scanning tunneling microscopy is used to investigate isomerization of amino-nitro-azobenzene on a thin NaCl layer on Ag(111) by inelastically tunneling electrons. A reversible isomerization between a planar trans and a three-dimensional cis form with two different thresholds is demonstrated. The isomerization characteristics are rationalized in terms of binding of the multipolar molecule to the ionic layer. This study shows the feasibility of a bistable single molecule switch on an insulator.
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Affiliation(s)
- Ali Safiei
- Institut für Festkörperphysik, Abteilung ATMOS, Leibniz Universität Hannover, Appelstrasse 2, D-30167 Hannover, Germany
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35
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Henzl J, Morgenstern K. An electron induced two-dimensional switch made of azobenzene derivatives anchored in supramolecular assemblies. Phys Chem Chem Phys 2010; 12:6035-44. [PMID: 20386802 DOI: 10.1039/b924488c] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Supramolecular assemblies of 4-anilino-4'-nitroazobenzene are investigated on the Au(111) surface by low temperature scanning tunneling microscopy and spectroscopy with submolecular resolution. Adsorption at 250 K leads to three different structures that are formed via hydrogen bonds: a star structure and two types of line structures: a meandering and a zigzag line. The formation of these supramolecular assemblies is affected by the available space on the fcc domains of the reconstructed Au(111) substrate as well as by the two-dimensional chirality of the molecules on the surface. The star structure is enantiomerically pure, while both types of lines consist of a racemic mixture. Bonding between homochiral pairs differ from the one between heterochiral pairs in the position of the hydrogen bonds. Inside these supramolecular assemblies two configurations of the molecules are identified: An almost straight trans-configuration and a slightly bent cis*-configuration. The trans-configuration largely reflects the structure of this isomer in gas phase, while the cis*-configuration is two-dimensional on the surface in contrast to the three-dimensional gas phase cis-configuration. The reversible trans-cis* isomerization is induced by electron tunneling through the LUMO+1 state of the molecule, which is located at +2.9 V.
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Affiliation(s)
- Jörg Henzl
- Leibniz Universität Hannover, Institut für Festkörperphysik, Abteilung für atomare und molekulare Strukturen (ATMOS), Appelstr. 2, D-30167 Hannover, Germany.
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36
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Schmidt R, Hagen S, Brete D, Carley R, Gahl C, Dokić J, Saalfrank P, Hecht S, Tegeder P, Weinelt M. On the electronic and geometrical structure of the trans- and cis-isomer of tetra-tert-butyl-azobenzene on Au(111). Phys Chem Chem Phys 2010; 12:4488-97. [DOI: 10.1039/b924409c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Sridevi S, Prasad SK, Nair GG. Electric-field-dictated phase diagram and accelerated dynamics of a reentrant nematic liquid crystal under photostimulation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:021703. [PMID: 19792142 DOI: 10.1103/physreve.80.021703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Indexed: 05/28/2023]
Abstract
In a system consisting of photoactive molecules that exhibit light-driven isomerization transformations, actinic light can diminish or enhance ordering to the extent that transitions from the equilibrium to a more disordered phase can be brought about isothermally. This feature enables light to be used as a thermodynamiclike parameter to investigate phase behavior and adds another dimension to the studies owing to the nonequilibrium character of the isothermal transitions. We have carried out experiments which exploit the combination of two recent findings, viz., an electric field can accelerate the return to the nematic liquid crystalline phase from a photodriven isotropic phase; and in a reentrant mesogen, the photoinduced phase can be more ordered. To photostimulate the nonequilibrium transitions a low power uv radiation (0.1 mW cm(-2)) has been used. Unique temperature-electric-field phase diagrams of a liquid crystal exhibiting isotropic-nematic-smectic- A -reentrant nematic sequence, mapped using light transmission as probe reveal that the electric field influences all the transitions, but the effect is maximum on the equilibrium reentrant nematic to the photoinduced smectic- A transition. Temporal measurements have been performed under nonequilibrium conditions to study the dynamics of both the photochemical and the back relaxation processes across the different transitions. The electric field is indeed observed to accelerate the thermal back relaxation in each case, and especially the recovery of the reentrant phase is hastened by three orders of magnitude in time. We explore possible causes for the acceleration and present a finding which can be associated with one of the predictions of density-functional calculations for isomerization of azobenzenes.
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Affiliation(s)
- S Sridevi
- Centre for Liquid Crystal Research, Jalahalli, Bangalore 560 013, India
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38
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Dokić J, Gothe M, Wirth J, Peters MV, Schwarz J, Hecht S, Saalfrank P. Quantum Chemical Investigation of Thermal Cis-to-Trans Isomerization of Azobenzene Derivatives: Substituent Effects, Solvent Effects, and Comparison to Experimental Data. J Phys Chem A 2009; 113:6763-73. [DOI: 10.1021/jp9021344] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jadranka Dokić
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany, and Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Marcel Gothe
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany, and Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Jonas Wirth
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany, and Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Maike V. Peters
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany, and Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Jutta Schwarz
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany, and Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Stefan Hecht
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany, and Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Peter Saalfrank
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany, and Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
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Wang L, Xu W, Yi C, Wang X. Isomerization and electronic relaxation of azobenzene after being excited to higher electronic states. J Mol Graph Model 2009; 27:792-6. [DOI: 10.1016/j.jmgm.2008.11.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 11/20/2008] [Accepted: 11/21/2008] [Indexed: 11/17/2022]
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Riedel D, Cranney M, Martin M, Guillory R, Dujardin G, Dubois M, Sonnet P. Surface-Isomerization Dynamics of trans-Stilbene Molecules Adsorbed on Si(100)-2×1. J Am Chem Soc 2009; 131:5414-23. [DOI: 10.1021/ja807498v] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Damien Riedel
- Laboratoire de Photophysique Moléculaire, CNRS (UPR 3361), Bât. 210, Centre Universitaire de Paris Sud, F91405 ORSAY, France, MINATEC/INPG/IMEP, 3 Parvis Louis Néel, BP 257, F-38016 Grenoble Cedex 1, France, and Institut de Science des Matériaux de Mulhouse (IS2M) LRC CNRS 7228 - Université de Haute Alsace 7014 4, rue des Frères Lumière 68093 Mulhouse Cedex, France
| | - Marion Cranney
- Laboratoire de Photophysique Moléculaire, CNRS (UPR 3361), Bât. 210, Centre Universitaire de Paris Sud, F91405 ORSAY, France, MINATEC/INPG/IMEP, 3 Parvis Louis Néel, BP 257, F-38016 Grenoble Cedex 1, France, and Institut de Science des Matériaux de Mulhouse (IS2M) LRC CNRS 7228 - Université de Haute Alsace 7014 4, rue des Frères Lumière 68093 Mulhouse Cedex, France
| | - Marta Martin
- Laboratoire de Photophysique Moléculaire, CNRS (UPR 3361), Bât. 210, Centre Universitaire de Paris Sud, F91405 ORSAY, France, MINATEC/INPG/IMEP, 3 Parvis Louis Néel, BP 257, F-38016 Grenoble Cedex 1, France, and Institut de Science des Matériaux de Mulhouse (IS2M) LRC CNRS 7228 - Université de Haute Alsace 7014 4, rue des Frères Lumière 68093 Mulhouse Cedex, France
| | - Romain Guillory
- Laboratoire de Photophysique Moléculaire, CNRS (UPR 3361), Bât. 210, Centre Universitaire de Paris Sud, F91405 ORSAY, France, MINATEC/INPG/IMEP, 3 Parvis Louis Néel, BP 257, F-38016 Grenoble Cedex 1, France, and Institut de Science des Matériaux de Mulhouse (IS2M) LRC CNRS 7228 - Université de Haute Alsace 7014 4, rue des Frères Lumière 68093 Mulhouse Cedex, France
| | - Gérald Dujardin
- Laboratoire de Photophysique Moléculaire, CNRS (UPR 3361), Bât. 210, Centre Universitaire de Paris Sud, F91405 ORSAY, France, MINATEC/INPG/IMEP, 3 Parvis Louis Néel, BP 257, F-38016 Grenoble Cedex 1, France, and Institut de Science des Matériaux de Mulhouse (IS2M) LRC CNRS 7228 - Université de Haute Alsace 7014 4, rue des Frères Lumière 68093 Mulhouse Cedex, France
| | - Mathieu Dubois
- Laboratoire de Photophysique Moléculaire, CNRS (UPR 3361), Bât. 210, Centre Universitaire de Paris Sud, F91405 ORSAY, France, MINATEC/INPG/IMEP, 3 Parvis Louis Néel, BP 257, F-38016 Grenoble Cedex 1, France, and Institut de Science des Matériaux de Mulhouse (IS2M) LRC CNRS 7228 - Université de Haute Alsace 7014 4, rue des Frères Lumière 68093 Mulhouse Cedex, France
| | - Philippe Sonnet
- Laboratoire de Photophysique Moléculaire, CNRS (UPR 3361), Bât. 210, Centre Universitaire de Paris Sud, F91405 ORSAY, France, MINATEC/INPG/IMEP, 3 Parvis Louis Néel, BP 257, F-38016 Grenoble Cedex 1, France, and Institut de Science des Matériaux de Mulhouse (IS2M) LRC CNRS 7228 - Université de Haute Alsace 7014 4, rue des Frères Lumière 68093 Mulhouse Cedex, France
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Klaumünzer B, Kröner D. N-Inversion in 2-azabicyclopentane derivatives: model simulations for a laser controlled molecular switch. NEW J CHEM 2009. [DOI: 10.1039/b812319e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Klamroth T, Kröner D. Stereoselective isomerization of an ensemble of adsorbed molecules with multiple orientations: stochastic laser pulse optimization for selective switching between achiral and chiral atropisomers. J Chem Phys 2008; 129:234701. [PMID: 19102546 DOI: 10.1063/1.3036927] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We present quantum dynamical simulations for the laser driven isomerization of an ensemble of surface mounted stereoisomers with multiple orientations. The model system 1-(2-cis-fluoroethenyl)-2-fluorobenzene supports two chiral and one achiral atropisomers upon torsion around the C-C single bond connecting phenyl ring and ethylene group. An infrared picosecond pulse is used to excite the internal rotation around the chiral axis, thereby controlling the chirality of the molecule. In order to selectively switch the molecules--independent of their orientation on a surface--from their achiral to either their left- or right-handed form, a stochastic pulse optimization algorithm is applied. The stochastic pulse optimization is performed for different sets of defined orientations of adsorbates corresponding to the rotational symmetry of the surface. The obtained nonlinearly polarized laser pulses are highly enantioselective for each orientation.
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Affiliation(s)
- Tillmann Klamroth
- Institut für Chemie, Theoretische Chemie, Universität Potsdam, D-14476 Potsdam, Germany.
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Henningsen N, Franke KJ, Schulze G, Fernández-Torrente I, Priewisch B, Rück-Braun K, Pascual JI. Active Intramolecular Conformational Dynamics Controlling the Assembly of Azobenzene Derivatives at Surfaces. Chemphyschem 2008; 9:71-3. [DOI: 10.1002/cphc.200700678] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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45
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Sauer P, Allen RE. Multiple steps and multiple excitations in photoisomerization of azobenzene. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2007.11.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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Alemani M, Peters MV, Hecht S, Rieder KH, Moresco F, Grill L. Electric field-induced isomerization of azobenzene by STM. J Am Chem Soc 2007; 128:14446-7. [PMID: 17090013 DOI: 10.1021/ja065449s] [Citation(s) in RCA: 384] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The electric field applied between the tip of a scanning tunneling microscope and a metallic surface is shown to induce the reversible trans-cis isomerization of single azobenzene derivatives adsorbed on a Au(111) surface. The investigated molecule is symmetrically equipped with four tert-butyl groups, which decouple the azobenzene core from the metallic surface, facilitating the formation of highly ordered islands. Due to the spatial extension of the electric field, it is possible to switch many molecules within the same island simultaneously.
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Affiliation(s)
- Micol Alemani
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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47
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Reversible switching of tetra-tert-butyl-azobenzene on a Au(111) surface induced by light and thermal activation. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.07.005] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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