1
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Schlichter L, Jersch J, Demokritov SO, Ravoo BJ. Multi-Stimuli-Responsive Water-Dispersible Magnetite Nanoparticles Using Arylazopyrazole-Modified Polymer Ligands. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:13669-13675. [PMID: 38875303 DOI: 10.1021/acs.langmuir.4c01342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2024]
Abstract
In order to design new nanomaterials with improved functionalities, magnetite nanoparticles (MNP) modified with arylazopyrazole (AAP) molecular photoswitches are presented. Water dispersibility is achieved by using poly(acrylic acid) (pAA) as a multidentate ligand, which is modified with AAP by amide coupling. The polymer ligand stabilizes the MNP, allows for E-Z isomerization of the photoswitch, and provides pH responsiveness. Three different AAP are synthesized and attached to pAA via amide coupling giving pAA-AAP with photoswitches substituted statistically along the hydrophilic polymer backbone. MNP are synthesized by coprecipitation and pAA-AAP is introduced as a stabilizing agent in situ. Photoisomerization of pAA-AAP and pAA-AAP@MNP is investigated showing good photostationary states and cyclability. The MNP can be assembled and dispersed reversibly in water either by applying a magnetic field or by a change in pH.
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Affiliation(s)
- Lisa Schlichter
- Center for Soft Nanoscience and Organic Chemistry Institute, University of Münster, Busso-Peus-Straße 10, 48149 Münster, Germany
| | - Johann Jersch
- Institute of Applied Physics, University of Münster, Corrensstraße 2, 48149 Münster, Germany
| | - Sergej O Demokritov
- Institute of Applied Physics, University of Münster, Corrensstraße 2, 48149 Münster, Germany
| | - Bart Jan Ravoo
- Center for Soft Nanoscience and Organic Chemistry Institute, University of Münster, Busso-Peus-Straße 10, 48149 Münster, Germany
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2
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Li M, Liu M, Qi F, Lin FR, Jen AKY. Self-Assembled Monolayers for Interfacial Engineering in Solution-Processed Thin-Film Electronic Devices: Design, Fabrication, and Applications. Chem Rev 2024; 124:2138-2204. [PMID: 38421811 DOI: 10.1021/acs.chemrev.3c00396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Interfacial engineering has long been a vital means of improving thin-film device performance, especially for organic electronics, perovskites, and hybrid devices. It greatly facilitates the fabrication and performance of solution-processed thin-film devices, including organic field effect transistors (OFETs), organic solar cells (OSCs), perovskite solar cells (PVSCs), and organic light-emitting diodes (OLEDs). However, due to the limitation of traditional interfacial materials, further progress of these thin-film devices is hampered particularly in terms of stability, flexibility, and sensitivity. The deadlock has gradually been broken through the development of self-assembled monolayers (SAMs), which possess distinct benefits in transparency, diversity, stability, sensitivity, selectivity, and surface passivation ability. In this review, we first showed the evolution of SAMs, elucidating their working mechanisms and structure-property relationships by assessing a wide range of SAM materials reported to date. A comprehensive comparison of various SAM growth, fabrication, and characterization methods was presented to help readers interested in applying SAM to their works. Moreover, the recent progress of the SAM design and applications in mainstream thin-film electronic devices, including OFETs, OSCs, PVSCs and OLEDs, was summarized. Finally, an outlook and prospects section summarizes the major challenges for the further development of SAMs used in thin-film devices.
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Affiliation(s)
- Mingliang Li
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Ming Liu
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Feng Qi
- Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Francis R Lin
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Alex K-Y Jen
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong 999077, China
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3
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Schmitt T, Huck C, Oberhof N, Hsu LY, Blasco E, Dreuw A, Tegeder P. Characteristics and long-term kinetics of an azobenzene derivative and a donor-acceptor Stenhouse adduct as orthogonal photoswitches. Phys Chem Chem Phys 2024; 26:7190-7202. [PMID: 38349743 DOI: 10.1039/d3cp05786k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Light-triggered molecular switches are extensively researched for their applications in medicine, chemistry and material science and, if combined, particularly for their use in multifunctional smart materials, for which orthogonally, i.e. individually, addressable photoswitches are needed. In such a multifunctional mixture, the switching properties, efficiencies and the overall performance may be impaired by undesired mutual dependences of the photoswitches on each other. Within this study, we compare the performance of the pure photoswitches, namely an azobenzene derivative (Azo) and a donor-acceptor Stenhouse adduct (DASA), with the switching properties of their mixture using time-resolved temperature-dependent UV/VIS absorption spectroscopy, time-resolved IR absorption spectroscopy at room temperature and quantum mechanical calculations to determine effective cross sections, switching kinetics as well as activation energies of thermally induced steps. We find slightly improved effective cross sections, percentages of switched molecules and no increased activation barriers of the equimolar mixture compared to the single compounds. Thus, the studied mixture Azo + DASA is very promising for future applications in multifunctional smart materials.
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Affiliation(s)
- Tanja Schmitt
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany.
| | - Christian Huck
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany.
| | - Nils Oberhof
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
| | - Li-Yun Hsu
- Institute for Molecular System Engineering and Advanced Materials, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
| | - Eva Blasco
- Institute for Molecular System Engineering and Advanced Materials, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
| | - Andreas Dreuw
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
| | - Petra Tegeder
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany.
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4
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Severa L, Santos Hurtado C, Rončević I, Mašát M, Bastien G, Štoček JR, Dračínský M, Houska V, Kaletová E, Garza DJ, Císařová I, Cimatu KLA, Bastl Z, Kaleta J. Regular Arrays of Rod-Shaped Molecular Photoswitches: Synthesis, Preparation, Characterization, and Selective Photoswitching within Mono- and Bilayer Systems. Chemistry 2024; 30:e202302828. [PMID: 37858965 DOI: 10.1002/chem.202302828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 10/21/2023]
Abstract
We assembled photoresponsive mono- and bilayer systems with well-defined properties from rod-shaped molecules equipped with different photoswitches. Using properly chosen chromophores (diarylethene-based switch and unidirectional light-driven molecular motor), we then selectively targeted layers made of the same types of photoswitches using appropriate monochromatic light. UV-vis analysis confirmed smooth and unrestricted photoisomerization. To achieve this, we synthesized a new class of triptycene-based molecular pedestals adept at forming sturdy Langmuir-Blodgett films on a water-air interface. The films were smoothly transferred to gold and quartz surfaces. Repeated deposition afforded bilayer systems: one layer containing diarylethene-based photoswitches and the other a unidirectional light-driven molecular motor. Structural analysis of both mono- and bilayer systems revealed the molecules to be tilted with carboxylic functions pointing to the surface. At least two different polymorphs differing in monolayer thickness and tilt angle (~40° and ~60°) were identified on the gold surface.
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Affiliation(s)
- Lukáš Severa
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
| | - Carina Santos Hurtado
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
| | - Igor Rončević
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
| | - Milan Mašát
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
| | - Guillaume Bastien
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
| | - Jakub Radek Štoček
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
| | - Václav Houska
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
| | - Eva Kaletová
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
| | - Danielle John Garza
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
| | - Ivana Císařová
- Department of Inorganic Chemistry, Faculty of Science, Charles University Prague, Hlavova 2030, 128 40, Prague 2, Czech Republic
| | | | - Zdeněk Bastl
- J. Heyrovský Institute of Physical Chemistry of the, Czech Academy of Sciences, Dolejškova 2155/3, 182 23, Prague 8, Czech Republic
| | - Jiří Kaleta
- Institute of Organic Chemistry and Biochemistry of the, Czech Academy of Sciences, Flemingovo nám. 2, 160 00, Prague, Czech Republic
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5
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Kaletová E, Santos Hurtado C, Císařová I, Teat SJ, Kaleta J. Triptycene-Based Molecular Rods for Langmuir-Blodgett Monolayers. Chempluschem 2022; 87:e202200023. [PMID: 35195369 DOI: 10.1002/cplu.202200023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/04/2022] [Indexed: 11/06/2022]
Abstract
Herein we introduce fully modular synthesis leading to three representative examples of rigid molecular rods that are intended to form sturdy monolayers on various surfaces. These molecules contain two triptycene units that are designed to interlock into a compact "double-decker" structure. Two of the three final products provided suitable crystals for X-ray diffraction (analyzed on synchrotron), allowing deeper insight into packing in the 3-D crystal lattice. The acidity of all three compounds were determined by capillary electrophoresis, and the pKa values ranged between 2.06-2.53. All three rigid rods easily formed Langmuir-Blodgett monolayers (LBMs) on the water-air interfaces, with the area per molecule equal to 55-59 Å2 /molecule, suggesting tight intermolecular packing. The thickness of all three films reached ∼19 Å after transfer to a gold (111) surface, meaning that individual molecules are tilted maximally 38° from the axis perpendicular to the surface. The structure of one of these films on a gold (111) surface was visualized by AFM. These geometrically unique molecules represent promising platforms with a wide scope of applicability in the supramolecular architecture.
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Affiliation(s)
- Eva Kaletová
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 160 00, Prague 6, Czech Republic
| | - Carina Santos Hurtado
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 160 00, Prague 6, Czech Republic
| | - Ivana Císařová
- Department of Inorganic Chemistry Faculty of Science, Charles University in Prague, Hlavova 2030, 12840, Prague 2, Czech Republic
| | - Simon J Teat
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Jiří Kaleta
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 160 00, Prague 6, Czech Republic
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6
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Rusch TR, Schlimm A, Krekiehn NR, Tellkamp T, Budzák Š, Jacquemin D, Tuczek F, Herges R, Magnussen OM. Observation of Collective Photoswitching in Free-Standing TATA-Based Azobenzenes on Au(111). Angew Chem Int Ed Engl 2020; 59:17192-17196. [PMID: 32524693 PMCID: PMC7540444 DOI: 10.1002/anie.202003797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/04/2020] [Indexed: 11/29/2022]
Abstract
Light-induced transitions between the trans and cis isomer of triazatriangulenium-based azobenzene derivatives on Au(111) surfaces were observed directly by scanning tunneling microscopy, allowing atomic-scale studies of the photoisomerization kinetics. Although the azobenzene units in these adlayers are free-standing and spaced at uniform distances of 1.26 nm, their photoswitching depends on the isomeric state of the surrounding molecules and, specifically, is accelerated by neighboring cis isomers. These collective effects are supported by ab initio calculations indicating that the electronic excitation preferably localizes on the n-π* state of trans isomers with neighboring cis azobenzenes.
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Affiliation(s)
- Talina R. Rusch
- Institute of Experimental and Applied PhysicsChristian Albrechts UniversityKielGermany
| | - Alexander Schlimm
- Institute of Inorganic ChemistryChristian Albrechts UniversityKielGermany
| | - Nicolai R. Krekiehn
- Institute of Experimental and Applied PhysicsChristian Albrechts UniversityKielGermany
| | - Tobias Tellkamp
- Otto Diels Institute of Organic ChemistryChristian Albrechts UniversityKielGermany
| | - Šimon Budzák
- Department of ChemistryFaculty of Natural SciencesMatej Bel UniversityBanska BystricaSlovakia
| | | | - Felix Tuczek
- Institute of Inorganic ChemistryChristian Albrechts UniversityKielGermany
| | - Rainer Herges
- Otto Diels Institute of Organic ChemistryChristian Albrechts UniversityKielGermany
| | - Olaf M. Magnussen
- Institute of Experimental and Applied PhysicsChristian Albrechts UniversityKielGermany
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7
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Rusch TR, Schlimm A, Krekiehn NR, Tellkamp T, Budzák Š, Jacquemin D, Tuczek F, Herges R, Magnussen OM. Observation of Collective Photoswitching in Free‐Standing TATA‐Based Azobenzenes on Au(111). Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Talina R. Rusch
- Institute of Experimental and Applied Physics Christian Albrechts University Kiel Germany
| | - Alexander Schlimm
- Institute of Inorganic Chemistry Christian Albrechts University Kiel Germany
| | - Nicolai R. Krekiehn
- Institute of Experimental and Applied Physics Christian Albrechts University Kiel Germany
| | - Tobias Tellkamp
- Otto Diels Institute of Organic Chemistry Christian Albrechts University Kiel Germany
| | - Šimon Budzák
- Department of Chemistry Faculty of Natural Sciences Matej Bel University Banska Bystrica Slovakia
| | - Denis Jacquemin
- CEISAM Lab—UMR 6230— CNRS/University of Nantes Nantes France
| | - Felix Tuczek
- Institute of Inorganic Chemistry Christian Albrechts University Kiel Germany
| | - Rainer Herges
- Otto Diels Institute of Organic Chemistry Christian Albrechts University Kiel Germany
| | - Olaf M. Magnussen
- Institute of Experimental and Applied Physics Christian Albrechts University Kiel Germany
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8
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Riaz S, Friedrichs G. Vibrational sum-frequency generation study of molecular structure, sterical constraints and nonlinear optical switching contrast of mixed alkyl-azobenzene self-assembled monolayers. Z PHYS CHEM 2020. [DOI: 10.1515/zpch-2020-1655] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Abstract
Self-assembled monolayers (SAMs) of azobenzene (AB) functionalized alkyl thiols on gold diluted with simple alkyl thiols provide a straightforward way to photochromic surfaces with high and tunable photoswitching efficiency. Trans-cis isomerization of the AB molecule changes the physical properties of the surface, including the nonlinear optical (NLO) response. Vibrational sum-frequency generation (VSFG) spectroscopy as a nonlinear type of laser spectroscopy offers surface- and orientation-sensitive insight into the molecular structure of mixed SAMs. In this study, VSFG as well as ultraviolet-visible (UV/Vis) spectroscopy has been employed to investigate the morphology, molecular structure, and NLO response of mixed SAMs with systematically varied surface composition. Methylazobenzene (MeAB) has been used as the molecular switch with the methyl substituent serving as orientational VSFG marker. Both short-chain and long-chain alkyl thiol co-ligands have been used to gain insight into the interplay between SAM structure and sterical constraints that are known to limit the free switching volume. Underlining the dominating role of sterical effects for controlling photochromic properties, a strong inhibition of the photoswitching efficiency and NLO response has been observed for the SAMs with an alkyl thiol co-ligand long enough to spatially extend into the layer of the MeAB chromophore. Overall, with <12% signal change, the relative NLO switching contrasts remained low in all cases. VSFG spectral trends clearly revealed that the presumably higher photoswitching efficiency upon dilution with the co-ligand is counteracted by a loss of structural order of the chromophore.
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Affiliation(s)
- Saira Riaz
- Islamabad College for Girls , F-6/2 , Islamabad, 44000 , Pakistan
| | - Gernot Friedrichs
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel , Max-Eyth-Str. 1, 24118 , Kiel , Germany
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9
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Benneckendorf FS, Rohnacher V, Sauter E, Hillebrandt S, Münch M, Wang C, Casalini S, Ihrig K, Beck S, Jänsch D, Freudenberg J, Jaegermann W, Samorì P, Pucci A, Bunz UHF, Zharnikov M, Müllen K. Tetrapodal Diazatriptycene Enforces Orthogonal Orientation in Self-Assembled Monolayers. ACS APPLIED MATERIALS & INTERFACES 2020; 12:6565-6572. [PMID: 31825591 DOI: 10.1021/acsami.9b16062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Conformationally rigid multipodal molecules should control the orientation and packing density of functional head groups upon self-assembly on solid supports. Common tripods frequently fail in this regard because of inhomogeneous bonding configuration and stochastic orientation. These issues are circumvented by a suitable tetrapodal diazatriptycene moiety, bearing four thiol-anchoring groups, as demonstrated in the present study. Such molecules form well-defined self-assembled monolayers (SAMs) on Au(111) substrates, whereby the tetrapodal scaffold enforces a nearly upright orientation of the terminal head group with respect to the substrate, with at least three of the four anchoring groups providing thiolate-like covalent attachment to the surface. Functionalization by condensation chemistry allows a large variety of functional head groups to be introduced to the tetrapod, paving the path toward advanced surface engineering and sensor fabrication.
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Affiliation(s)
- Frank S Benneckendorf
- Organisch-Chemisches Institut , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
| | - Valentina Rohnacher
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Kirchhoff-Institut für Physik , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 227 , 69120 Heidelberg , Germany
| | - Eric Sauter
- Angewandte Physikalische Chemie , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 253 , 69120 Heidelberg , Germany
| | - Sabina Hillebrandt
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy , University of St Andrews , North Haugh , St Andrews KY16 9SS , United Kingdom
- Kirchhoff-Institut für Physik , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 227 , 69120 Heidelberg , Germany
| | - Maybritt Münch
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Materials Science Department, Surface Science Division , TU Darmstadt , Otto-Berndt-Straße 3 , 64287 Darmstadt , Germany
| | - Can Wang
- University of Strasbourg , CNRS, ISIS, 8 allée Gaspard Monge , 67000 Strasbourg , France
| | - Stefano Casalini
- University of Strasbourg , CNRS, ISIS, 8 allée Gaspard Monge , 67000 Strasbourg , France
| | - Katharina Ihrig
- Organisch-Chemisches Institut , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
| | - Sebastian Beck
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Kirchhoff-Institut für Physik , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 227 , 69120 Heidelberg , Germany
| | - Daniel Jänsch
- Organisch-Chemisches Institut , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
| | - Jan Freudenberg
- Organisch-Chemisches Institut , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
| | - Wolfram Jaegermann
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Materials Science Department, Surface Science Division , TU Darmstadt , Otto-Berndt-Straße 3 , 64287 Darmstadt , Germany
| | - Paolo Samorì
- University of Strasbourg , CNRS, ISIS, 8 allée Gaspard Monge , 67000 Strasbourg , France
| | - Annemarie Pucci
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Kirchhoff-Institut für Physik , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 227 , 69120 Heidelberg , Germany
- Centre for Advanced Materials , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 225 , 69120 Heidelberg , Germany
| | - Uwe H F Bunz
- Organisch-Chemisches Institut , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
- Centre for Advanced Materials , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 225 , 69120 Heidelberg , Germany
| | - Michael Zharnikov
- Angewandte Physikalische Chemie , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 253 , 69120 Heidelberg , Germany
| | - Klaus Müllen
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Max Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany
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10
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Kunfi A, Bernadett Vlocskó R, Keresztes Z, Mohai M, Bertóti I, Ábrahám Á, Kiss É, London G. Photoswitchable Macroscopic Solid Surfaces Based On Azobenzene-Functionalized Polydopamine/Gold Nanoparticle Composite Materials: Formation, Isomerization and Ligand Exchange. Chempluschem 2020; 85:797-805. [PMID: 31967410 DOI: 10.1002/cplu.201900674] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 01/07/2020] [Indexed: 12/21/2022]
Abstract
The facile preparation of dynamic interfaces is presented based on the combination of photoisomerizable azobenzenes and polydopamine (PDA)/Au nanoparticle composite materials. Azobenzenes with different spacer lengths (C3 , C6 ) and surface-binding groups (SH, NH2 ) were synthesized. The polymer layer on macroscopic quartz surface was prepared by the facile aerobic autopolymerisation of dopamine hydrochloride under basic conditions. The presence of redox-active catechol moieties meant that gold nanoparticles were formed on the polymer surface. The obtained UV-Vis spectroscopic results confirmed that following their successful assembly, the switching of azobenzenes on PDA/Au was not affected by the surface binding group and the spacer length of the azobenzene molecules under the measurement conditions. Furthermore, facilitated by the curved nature of the Au particles, the surface-bound azobenzene layer could be reconstructed by ligand-exchange processes, and the photochemical characterization of the mixed layer was performed.
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Affiliation(s)
- Attila Kunfi
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2., 1117, Budapest, Hungary.,Department of Organic Chemistry, University of Szeged, Dóm tér 8, 6720, Szeged, Hungary
| | - Rita Bernadett Vlocskó
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2., 1117, Budapest, Hungary
| | - Zsófia Keresztes
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2., 1117, Budapest, Hungary
| | - Miklós Mohai
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2., 1117, Budapest, Hungary
| | - Imre Bertóti
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2., 1117, Budapest, Hungary
| | - Ágnes Ábrahám
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2., 1117, Budapest, Hungary.,Laboratory of Interfaces and Nanostructures, Eötvös Loránd University, Pázmány Péter stny. 1/A, 1117, Budapest, Hungary
| | - Éva Kiss
- Laboratory of Interfaces and Nanostructures, Eötvös Loránd University, Pázmány Péter stny. 1/A, 1117, Budapest, Hungary
| | - Gábor London
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2., 1117, Budapest, Hungary
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11
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Raab M, Becca JC, Heo J, Lim CK, Baev A, Jensen L, Prasad PN, Velarde L. Doubly resonant sum frequency spectroscopy of mixed photochromic isomers on surfaces reveals conformation-specific vibronic effects. J Chem Phys 2019; 150:114704. [DOI: 10.1063/1.5081726] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Micah Raab
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
- The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo, Buffalo, New York 14260, USA
| | - Jeffrey C. Becca
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, USA
| | - Jeongyun Heo
- The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo, Buffalo, New York 14260, USA
| | - Chang-Keun Lim
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
- The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo, Buffalo, New York 14260, USA
| | - Alexander Baev
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
- The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo, Buffalo, New York 14260, USA
| | - Lasse Jensen
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, USA
| | - Paras N. Prasad
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
- The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo, Buffalo, New York 14260, USA
| | - Luis Velarde
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
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12
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Ishiwari F, Nascimbeni G, Sauter E, Tago H, Shoji Y, Fujii S, Kiguchi M, Tada T, Zharnikov M, Zojer E, Fukushima T. Triptycene Tripods for the Formation of Highly Uniform and Densely Packed Self-Assembled Monolayers with Controlled Molecular Orientation. J Am Chem Soc 2019; 141:5995-6005. [PMID: 30869881 PMCID: PMC6483319 DOI: 10.1021/jacs.9b00950] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
When
employing self-assembled monolayers (SAMs) for tuning surface
and interface properties, organic molecules that enable strong binding
to the substrate, large-area structural uniformity, precise alignment
of functional groups, and control of their density are highly desirable.
To achieve these goals, tripod systems bearing multiple bonding sites
have been developed as an alternative to conventional monodentate
systems. Bonding of all three sites has, however, hardly been achieved,
with the consequence that structural uniformity and orientational
order in tripodal SAMs are usually quite poor. To overcome that problem,
we designed 1,8,13-trimercaptomethyltriptycene (T1) and
1,8,13-trimercaptotriptycene (T2) as potential tripodal
SAM precursors and investigated their adsorption behavior on Au(111)
combining several advanced experimental techniques and state-of-the-art
theoretical simulations. Both SAMs adopt dense, nested hexagonal structures
but differ in their adsorption configurations and structural uniformity.
While the T2-based SAM exhibits a low degree of order
and noticeable deviation from the desired tripodal anchoring, all
three anchoring groups of T1 are equally bonded to the
surface as thiolates, resulting in an almost upright orientation of
the benzene rings and large-area structural uniformity. These superior
properties are attributed to the effect of conformationally flexible
methylene linkers at the anchoring groups, absent in the case of T2. Both SAMs display interesting electronic properties, and,
bearing in mind that the triptycene framework can be functionalized
by tail groups in various positions and with high degree of alignment,
especially T1 appears as an ideal docking platform for
complex and highly functional molecular films.
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Affiliation(s)
| | - Giulia Nascimbeni
- Institute of Solid State Physics, NAWI Graz , Graz University of Technology , Petersgasse 16 , Graz 8010 , Austria
| | - Eric Sauter
- Applied Physical Chemistry , Heidelberg University , Im Neuenheimer Feld 253 , Heidelberg 69120 , Germany
| | | | | | - Shintaro Fujii
- Department of Chemistry, Graduate School of Science and Engineering , Tokyo Institute of Technology , Meguro , Tokyo 152-8551 , Japan
| | - Manabu Kiguchi
- Department of Chemistry, Graduate School of Science and Engineering , Tokyo Institute of Technology , Meguro , Tokyo 152-8551 , Japan
| | | | - Michael Zharnikov
- Applied Physical Chemistry , Heidelberg University , Im Neuenheimer Feld 253 , Heidelberg 69120 , Germany
| | - Egbert Zojer
- Institute of Solid State Physics, NAWI Graz , Graz University of Technology , Petersgasse 16 , Graz 8010 , Austria
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13
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Jasper-Tönnies T, Poltavsky I, Ulrich S, Moje T, Tkatchenko A, Herges R, Berndt R. Stability of functionalized platform molecules on Au(111). J Chem Phys 2018; 149:244705. [PMID: 30599747 DOI: 10.1063/1.5059344] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Trioxatriangulenium (TOTA) platform molecules were functionalized with methyl, ethyl, ethynyl, propynyl, and hydrogen and sublimated onto Au(111) surfaces. Low-temperature scanning tunneling microscopy data reveal that >99% of ethyl-TOTA and methyl-TOTA remain intact, whereas 60% of H-TOTA and >99% of propynyl-TOTA and ethynyl-TOTA decompose. The observed tendency toward fragmentation on Au(111) is opposite to the sequence of gas-phase stabilities of the molecules. Although Au(111) is the noblest of all metal surfaces, the binding energies of the decomposition products to Au(111) destabilize the functionalized platforms by 2 to 3.9 eV (190-370 kJ/mol) and even render some of them unstable as revealed by density functional theory calculations. Van der Waals forces are important, as they drive the adsorption of the platform molecules.
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Affiliation(s)
- Torben Jasper-Tönnies
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Igor Poltavsky
- Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg City L-1511, Luxembourg
| | - Sandra Ulrich
- Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Tobias Moje
- Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Alexandre Tkatchenko
- Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg City L-1511, Luxembourg
| | - Rainer Herges
- Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Richard Berndt
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
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14
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Nacci C, Baroncini M, Credi A, Grill L. Reversible Photoswitching and Isomer-Dependent Diffusion of Single Azobenzene Tetramers on a Metal Surface. Angew Chem Int Ed Engl 2018; 57:15034-15039. [PMID: 30187995 PMCID: PMC6237119 DOI: 10.1002/anie.201806536] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Indexed: 11/07/2022]
Abstract
Azobenzene is a prototypical molecular switch that can be reversibly photoisomerized between the nearly planar and apolar trans form, and the distorted, polar cis form. Most studies related to azobenzene derivatives have focused on planar adsorbed molecules. We present herein the study of a three-dimensional shape-persistent molecular architecture consisting of four tetrahedrally arranged azobenzene units that is adsorbed on a Ag(111) surface. While the azobenzenes of the tripod in contact with the surface lost their switching ability, different isomers of the upright standing arm of the tetramer were obtained reversibly and efficiently by illumination at different wavelengths, revealing time constants of only a few minutes. Diffusion on the surface was dependent on the isomeric state-trans or cis-of the upright oriented azobenzene group. Hence, molecular mobility can be modulated by its isomeric state, which suggests that molecular growth processes could be controlled by external stimuli.
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Affiliation(s)
- Christophe Nacci
- Department of Physical ChemistryUniversity of GrazHeinrichstrasse 288010GrazAustria
| | - Massimo Baroncini
- Dipartimento di Scienze e Tecnologie Agro-AlimentariUniversità di BolognaViale Fanin 5040127BolognaItaly
- CLAN-Center for Light Activated NanostructuresIstituto ISOF-CNRvia Gobetti 10140129BolognaItaly
| | - Alberto Credi
- Dipartimento di Scienze e Tecnologie Agro-AlimentariUniversità di BolognaViale Fanin 5040127BolognaItaly
- CLAN-Center for Light Activated NanostructuresIstituto ISOF-CNRvia Gobetti 10140129BolognaItaly
| | - Leonhard Grill
- Department of Physical ChemistryUniversity of GrazHeinrichstrasse 288010GrazAustria
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15
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Nacci C, Baroncini M, Credi A, Grill L. Reversible Photoswitching and Isomer‐Dependent Diffusion of Single Azobenzene Tetramers on a Metal Surface. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201806536] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Christophe Nacci
- Department of Physical ChemistryUniversity of Graz Heinrichstrasse 28 8010 Graz Austria
| | - Massimo Baroncini
- Dipartimento di Scienze e Tecnologie Agro-AlimentariUniversità di Bologna Viale Fanin 50 40127 Bologna Italy
- CLAN-Center for Light Activated NanostructuresIstituto ISOF-CNR via Gobetti 101 40129 Bologna Italy
| | - Alberto Credi
- Dipartimento di Scienze e Tecnologie Agro-AlimentariUniversità di Bologna Viale Fanin 50 40127 Bologna Italy
- CLAN-Center for Light Activated NanostructuresIstituto ISOF-CNR via Gobetti 101 40129 Bologna Italy
| | - Leonhard Grill
- Department of Physical ChemistryUniversity of Graz Heinrichstrasse 28 8010 Graz Austria
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16
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McElhinny KM, Park J, Ahn Y, Huang P, Joo Y, Lakkham A, Pateras A, Wen H, Gopalan P, Evans PG. Photoisomerization Dynamics in a Densely Packed Optically Transformable Azobenzene Monolayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10828-10836. [PMID: 30145906 DOI: 10.1021/acs.langmuir.8b01524] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Molecular monolayers that can be reconfigured through the use of external stimuli promise to enable the creation of interfaces with precisely selected dynamically adjustable physical and electronic properties with potential impact ranging from electronics to energy storage. Azobenzene-containing molecular monolayers have multiple stable molecular conformations but face a challenging nanoscale problem associated with understanding the basic mechanisms of reconfiguration. Time-resolved X-ray reflectivity studies show that the reconfiguration of a densely packed rhenium-azobenzene monolayer occurs in a period of many seconds. The degree of reconfiguration from trans to cis forms depends on the integrated UV fluence and has kinetics that are consistent with a mechanism in which the transformation occurs through the nucleation and growth of nanoscale two-dimensional regions of the cis isomer.
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Affiliation(s)
- Kyle M McElhinny
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Joonkyu Park
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Youngjun Ahn
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Peishen Huang
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Yongho Joo
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Arunee Lakkham
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Anastasios Pateras
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Haidan Wen
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Padma Gopalan
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Paul G Evans
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
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17
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Streubel S, Schulze-Zachau F, Weißenborn E, Braunschweig B. Ion Pairing and Adsorption of Azo Dye/C 16TAB Surfactants at the Air-Water Interface. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:27992-28000. [PMID: 29285205 PMCID: PMC5742476 DOI: 10.1021/acs.jpcc.7b08924] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/29/2017] [Indexed: 06/01/2023]
Abstract
Mixed layers of 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate (Sunset Yellow, SSY) and cetyltrimethylammonium bromide (C16TAB) at the air-water interface were studied using vibrational sum-frequency generation (SFG) and dynamic surface tension measurements. In the bulk, addition of C16TAB to SSY aqueous solution causes substantial changes in UV/vis absorption spectra, which originate from strong electrostatic interactions between the anionic SSY azo dye with the cationic C16TAB surfactant. These interactions are a driving force for the formation of SSY/C16TAB ion pairs. The latter are found to be highly surface active while free SSY molecules show no surface activity. Dynamic SFG as well as surface tension measurements at low SSY concentrations reveal that free C16TAB surfactants adsorb at the air-water interface on time scales <1 s where they initially form the dominating surface species, but on longer time scales free C16TAB is exchanged by SSY/C16TAB ion pairs. This causes a dramatic reduction of the surface tension to 35 mN/m but also in foam stability. These changes are accompanied by a substantial loss in SFG intensity from O-H stretching bands around 3200 and 3450 cm-1, which we relate to a decrease in surface charging due to adsorption of ion pairs with no or negligible net charges. For SSY/C16TAB molar ratios >0.5, the O-H bands in SFG spectra are reduced to very low intensities and are indicative to electrically neutral SSY/C16TAB ion pairs. This conclusion is corroborated by an analysis of macroscopic foams, which become highly instable in the presence of neutral SSY/C16TAB ion pairs. From an analysis of SFG spectra of air-water interfaces, we show that the electrostatic repulsion forces inside the ubiquitous foam films are reduced and thus remove the major stabilization mechanism within macroscopic foam.
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Affiliation(s)
- Saskia Streubel
- Institute of Physical Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - Felix Schulze-Zachau
- Institute of Physical Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - Eric Weißenborn
- Institute of Physical Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - Björn Braunschweig
- Institute of Physical Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
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18
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Cocchi C, Draxl C. Understanding the effects of packing and chemical terminations on the optical excitations of azobenzene-functionalized self-assembled monolayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:394005. [PMID: 28664870 DOI: 10.1088/1361-648x/aa7ca7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In a first-principles study based on many-body perturbation theory, we analyze the optical excitations of azobenzene-functionalized self-assembled monolayers (SAMs) with increasing packing density and different terminations, considering for comparison the corresponding gas-phase molecules and dimers. Intermolecular coupling increases with the density of the chromophores independently of the functional groups. The intense [Formula: see text] resonance that triggers photo-isomerization is present in the spectra of isolated dimers and diluted SAMs, but it is almost completely washed out in tightly packed architectures. Intermolecular coupling is partially inhibited by mixing differently functionalized azobenzene derivatives, in particular when large groups are involved. In this way, the excitation band inducing the photo-isomerization process is partially preserved and the effects of dense packing partly counterbalanced. Our results suggest that a tailored design of azobenzene-functionalized SAMs which optimizes the interplay between the packing density of the chromophores and their termination can lead to significant improvements in the photo-switching efficiency of these systems.
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Affiliation(s)
- Caterina Cocchi
- Physics Department and IRIS Adlershof, Humboldt-Universität zu Berlin, Berlin, Germany. European Theoretical Spectroscopic Facility (ETSF
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19
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Valášek M, Mayor M. Spatial and Lateral Control of Functionality by Rigid Molecular Platforms. Chemistry 2017; 23:13538-13548. [PMID: 28766790 DOI: 10.1002/chem.201703349] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Indexed: 11/11/2022]
Abstract
Surface mounted molecular devices have received significant attention in the scientific community because of their unique ability to construct functional materials. The key involves the platform on which the molecular device works on solid substrates, such as in solid-liquid or solid-vacuum interfaces. Here, we outline the concept of rigid molecular platforms to immobilize active functionality atop flat surfaces in a controllable manner. Most of these (multipodal) platforms have at least three anchoring groups to control the spatial arrangement of the protruding functional moieties and form mechanically stable and electronically tuned contacts to the underlying substrate. Another approach is based on employing of flat aromatic scaffolds bearing perpendicular functionalities that form stable lateral assemblies on various surfaces. Emphasis is placed on the need for controllable assembly and separation of these tailor-made molecules that expose functionalities at the molecular scale. The discussions are focused on the different molecular designs realizing functional 3D architectures on surfaces, the role of various anchoring strategies to control the spatial arrangement, and structural considerations controlling physical features like the coupling to the surface or the available space for sterically demanding molecular operations.
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Affiliation(s)
- Michal Valášek
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Marcel Mayor
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.,Lehn Institute of Functional Materials (LIFM), Sun Yat-Sen University (SYSU), Xingang Rd. W., Guangzhou, P. R. China.,Department of Chemistry, University of Basel, St. Johannsring 19, 4056, Basel, Switzerland
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20
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Stremlau S, Maass F, Tegeder P. Adsorption and switching properties of nitrospiropyran on Bi(1 1 4). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:314004. [PMID: 28604364 DOI: 10.1088/1361-648x/aa78be] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Spiropyrans are prototype molecular switches, which undergo a reversible photoinduced ring-opening/-closure reaction between the closed three-dimensional spiropyran (SP) and the open, planar merocyanine (MC) form. In solution the SP isomer is the thermodynamically stable form. Using high resolution electron energy loss spectroscopy, we resolve a thermally-activated irreversible ring-opening reaction of nitrospiropyran resulting in the MC form for coverages above one monolayer. Thus, the situation found in solution is reversed for the adsorbed molecules, since the MC form is more stable due to the modified energetics by the presence of the substrate. In addition, illumination with blue light (445 nm) induced also the ring-opening, while the photostimulated back-reaction could not be observed. The photoisomerization is driven by a substrate-mediated process, i.e. a charge transfer from the substrate into molecular states. The situation changes completely in the monolayer regime. Neither a thermally-assisted nor a photoinduced ring-opening reaction has been identified. We ascribe the suppression to sterical effects stabilizing the SP form due to the surface structure of Bi(1 1 4), which consists of straight atomic rows separated by rough valleys.
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Affiliation(s)
- Stephan Stremlau
- Ruprecht-Karls-Universität Heidelberg, Physikalisch-Chemisches Institut, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
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21
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Unger K, Salzmann P, Masciullo C, Cecchini M, Koller G, Coclite AM. Novel Light-Responsive Biocompatible Hydrogels Produced by Initiated Chemical Vapor Deposition. ACS APPLIED MATERIALS & INTERFACES 2017; 9:17408-17416. [PMID: 28475310 DOI: 10.1021/acsami.7b01527] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A novel multiresponsive hydrogel has been synthesized by initiated chemical vapor deposition (iCVD). Hydrogels are known for their dynamic swelling response to aqueous environments. A chemical functionalization of the hydrogel surface was performed to add other stimuli-responsive functionalities and obtain a smart material that responds to two stimuli: light irradiation and exposure to aqueous environment. Modifying the hydrogel surface with solution-based methods is often problematic because of the damages caused by the permeation of solvents in the hydrogel. This issue is completely bypassed by the use of solvent-free techniques. Cross-linked polymers of 2-hydroxyethyl methacrylate (HEMA) were functionalized with azobenzene groups, as confirmed by IR spectroscopy and X-ray photoelectron spectroscopy (XPS). Through photoisomerization of the azobenzene, the polarity within the hydrogel is modified and as a consequence the affinity to water. Light irradiation modifies the degree of swelling within thin hydrogel films from 13% before exposure to UV light to 25% after exposure. The possibility of controlling the degree and rate of swelling by light irradiation was never reported before on these time scales and can have exceptional implications for light-induced drug delivery or light-controlled microfluidic systems. The light-responsive hydrogels showed also biocompatibility, which makes them suitable for a great variety of applications as biomaterials.
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Affiliation(s)
- Katrin Unger
- Institute of Solid State Physics, NAWI Graz, Graz University of Technology , Petersgasse 16, 8010 Graz, Austria
| | - Paul Salzmann
- Institute of Solid State Physics, NAWI Graz, Graz University of Technology , Petersgasse 16, 8010 Graz, Austria
| | - Cecilia Masciullo
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore , Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Marco Cecchini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore , Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Georg Koller
- Surface and Interface Physics, Institute of Physics, NAWI Graz, University of Graz , Universitätsplatz 5, 8010 Graz, Austria
| | - Anna Maria Coclite
- Institute of Solid State Physics, NAWI Graz, Graz University of Technology , Petersgasse 16, 8010 Graz, Austria
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22
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McElhinny KM, Huang P, Joo Y, Kanimozhi C, Lakkham A, Sakurai K, Evans PG, Gopalan P. Optically Reconfigurable Monolayer of Azobenzene Donor Molecules on Oxide Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2157-2168. [PMID: 28170273 DOI: 10.1021/acs.langmuir.6b04585] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The structural configuration of molecules assembled at organic-inorganic interfaces within electronic materials strongly influences the functional electronic and vibrational properties relevant to applications ranging from energy storage to photovoltaics. Controlling and characterizing the structural state of an interface and its evolution under external stimuli is crucial both for the fundamental understanding of the factors influenced by molecular structure and for the development of methods for material synthesis. It has been challenging to create complete molecular monolayers that exhibit external reversible control of the structure and electronic configuration. We report a monolayer/inorganic interface consisting of an organic monolayer assembled on an oxide surface, exhibiting structural and electronic reconfiguration under ultraviolet illumination. The molecular monolayer is linked to the surface through a carboxylate link, with the backbone bearing an azobenzene functional group and the head group consisting of a rhenium-bipyridine group. Optical spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and X-ray reflectivity show that closely packed monolayers are formed from these molecules via the Langmuir-Blodgett technique. Reversible photoisomerization is observed in solution and in monolayers assembled on Si and quartz substrates. The reconfiguration of these monolayers provides additional means to control excitation and charge transfer processes that are important in applications in catalysis, molecular electronics, and solar energy conversion.
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Affiliation(s)
- Kyle M McElhinny
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Peishen Huang
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Yongho Joo
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Catherine Kanimozhi
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Arunee Lakkham
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Kenji Sakurai
- National Institute for Materials Science , Tsukuba, Ibaraki 305-4007, Japan
- University of Tsukuba , Tsukuba, Ibaraki 305-8577, Japan
| | - Paul G Evans
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Padma Gopalan
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
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23
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Moldt T, Przyrembel D, Schulze M, Bronsch W, Boie L, Brete D, Gahl C, Klajn R, Tegeder P, Weinelt M. Differing Isomerization Kinetics of Azobenzene-Functionalized Self-Assembled Monolayers in Ambient Air and in Vacuum. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:10795-10801. [PMID: 27681851 DOI: 10.1021/acs.langmuir.6b01690] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Azobenzenealkanethiols in self-assembled monolayers (SAMs) on Au(111) exhibit reversible trans-cis photoisomerization when diluted with alkanethiol spacers. Using these mixed SAMs, we show switching of the linear optical and second-harmonic response. The effective switching of these surface optical properties relies on a reasonably large cross section and a high photoisomerization yield as well as a long lifetime of the metastable cis isomer. We quantified the switching process by X-ray absorption spectroscopy. The cross sections for the trans-cis and cis-trans photoisomerization with 365 and 455 nm light, respectively, are 1 order of magnitude smaller than in solution. In vacuum, the 365 nm photostationary state comprises 50-74% of the molecules in the cis form, limited by their rapid thermal isomerization back to the trans state. In contrast, the 455 nm photostationary state contains nearly 100% trans-azobenzene. We determined time constants for the thermal cis-trans isomerization of only a few minutes in vacuum and in a dry nitrogen atmosphere but of more than 1 day in ambient air. Our results suggest that adventitious water adsorbed on the surface of the SAM stabilizes the polar cis configuration of azobenzene under ambient conditions. The back reaction rate constants differing by 2 orders of magnitude underline the huge influence of the environment and, accordingly, its importance when comparing various experiments.
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Affiliation(s)
- Thomas Moldt
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Daniel Przyrembel
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Michael Schulze
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg , 69120 Heidelberg, Germany
| | - Wibke Bronsch
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Larissa Boie
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Daniel Brete
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Cornelius Gahl
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Rafal Klajn
- Department of Organic Chemistry, Weizmann Institute of Science , 76100 Rehovot, Israel
| | - Petra Tegeder
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg , 69120 Heidelberg, Germany
| | - Martin Weinelt
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
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24
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Krekiehn NR, Müller M, Jung U, Ulrich S, Herges R, Magnussen OM. UV/Vis Spectroscopy Studies of the Photoisomerization Kinetics in Self-Assembled Azobenzene-Containing Adlayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:8362-8370. [PMID: 26134857 DOI: 10.1021/acs.langmuir.5b01645] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Direct comparative studies of the photoisomerization of azobenzene derivatives in self-assembled adlayers on Au and as free molecules in dichloromethane solution were performed using UV/vis spectroscopy. For all studied systems a highly reversible trans-cis isomerization in the adlayer is observed. Quantitative studies of the absorbance changes and photoisomerization kinetics reveal that in azobenzenes mounted as freestanding vertical groups on the surface via triazatriangulene-based molecular platforms photoswitching is nearly uninhibited by the local environment in the adlayer. The blue-shift of the π-π* transition in adlayers of these molecules is in good agreement with theoretical studies of the effect of excitonic coupling between the molecules. In contrast, in azobenzene-containing thiol self-assembled monolayers the fraction of photoswitching molecules and the photoisomerization kinetics are significantly reduced compared to free molecules in solution.
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Affiliation(s)
- N R Krekiehn
- †Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 19, 24118 Kiel, Germany
| | - M Müller
- †Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 19, 24118 Kiel, Germany
| | - U Jung
- †Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 19, 24118 Kiel, Germany
| | - S Ulrich
- ‡Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 4, 24098 Kiel, Germany
| | - R Herges
- ‡Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 4, 24098 Kiel, Germany
| | - O M Magnussen
- †Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 19, 24118 Kiel, Germany
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25
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Schulze M, Utecht M, Moldt T, Przyrembel D, Gahl C, Weinelt M, Saalfrank P, Tegeder P. Nonlinear optical response of photochromic azobenzene-functionalized self-assembled monolayers. Phys Chem Chem Phys 2015; 17:18079-86. [PMID: 26100382 DOI: 10.1039/c5cp03093e] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The combination of photochromic and nonlinear optical (NLO) properties of azobenzene-functionalized self-assembled monolayers (SAMs) constitutes an intriguing step towards novel photonic and optoelectronic devices. By utilizing the second-order NLO process of second harmonic generation (SHG), supported by density-functional theory and correlated wave function method calculations, we demonstrate that the photochromic interface provides the necessary prerequisites en route towards possible future technical applications: we find a high NLO contrast on the order of 16% between the switching states. These are furthermore accessible reversibly and with high efficiencies in terms of cross sections on the order of 10(-18) cm(2) for both photoisomerization reactions, i.e., drivable by means of low-power LED light sources. Finally, both photostationary states (PSSs) are thermally stable at ambient conditions.
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Affiliation(s)
- Michael Schulze
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heildeberg, Germany.
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26
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Chen J, Chen KY, Carroll GT, Feringa BL. Facile assembly of light-driven molecular motors onto a solid surface. Chem Commun (Camb) 2015; 50:12641-4. [PMID: 25198796 DOI: 10.1039/c4cc04440a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In order to improve the rotary motion of surface assembled light-driven molecular motors, tetra-acid-functionalized motors were bound to an amine-coated quartz surface without prior activation of the acid groups. In contrast to earlier bipodal motors, the tetravalent motor showed no significant reduction in the rotation speed when attached to a surface.
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Affiliation(s)
- Jiawen Chen
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands.
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27
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Schulze M, Utecht M, Hebert A, Rück-Braun K, Saalfrank P, Tegeder P. Reversible Photoswitching of the Interfacial Nonlinear Optical Response. J Phys Chem Lett 2015; 6:505-9. [PMID: 26261971 DOI: 10.1021/jz502477m] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Incorporating photochromic molecules into organic/inorganic hybrid materials may lead to photoresponsive systems. In such systems, the second-order nonlinear properties can be controlled via external stimulation with light at an appropriate wavelength. By creating photochromic molecular switches containing self-assembled monolayers on Si(111), we can demonstrate efficient reversible switching, which is accompanied by a pronounced modulation of the nonlinear optical (NLO) response of the system. The concept of utilizing functionalized photoswitchable Si surfaces could be a way for the generation of two-dimensional NLO switching materials, which are promising for applications in photonic and optoelectronic devices.
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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
| | - Manuel Utecht
- ¶Institut für Chemie, Theoretische Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Germany
| | - Andreas Hebert
- §Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Karola Rück-Braun
- §Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Peter Saalfrank
- ¶Institut für Chemie, Theoretische Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Germany
| | - Petra Tegeder
- †Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
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28
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Jacob H, Ulrich S, Jung U, Lemke S, Rusch T, Schütt C, Petersen F, Strunskus T, Magnussen O, Herges R, Tuczek F. Monitoring the reversible photoisomerization of an azobenzene-functionalized molecular triazatriangulene platform on Au(111) by IRRAS. Phys Chem Chem Phys 2014; 16:22643-50. [PMID: 25242068 DOI: 10.1039/c4cp03438d] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spectroscopic evidence of a reversible, photoinduced trans ↔ cis photoisomerization is provided for an azobenzene-functionalized triazatriangulene (TATA) platform on Au(111). As shown by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), these molecules form a well-ordered self-assembled monolayer (SAM) on Au(111). The surface-adsorbed azo-TATA platforms are also investigated by infrared reflection absorption spectroscopy (IRRAS); a methoxy marker group at the upper phenyl ring of the azo moiety is employed to monitor the switching state. The IRRAS data are analyzed by comparison with theoretical and transmission IR spectra as well as bulk and surface-enhanced Raman spectroscopic (SERS) data. IRRAS shows that the methoxy group is oriented perpendicular to the surface in trans- and tilted with respect to the surface normal in cis-configuration. This indicates that the photoswitching capability of the azobenzene moieties is retained on the gold surface. The lifetime of the cis-configuration is, however, reduced by a factor of ∼10(3) with respect to the homogeneous solution.
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Affiliation(s)
- Hanne Jacob
- Institut für Anorganische Chemie, Christian-Albrechts-Universität Kiel, Max-Eyth-Str. 2, 24118 Kiel, Germany.
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29
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Nachtigall O, Kördel C, Urner LH, Haag R. Photoresponsive Switches at Surfaces Based on Supramolecular Functionalization with Azobenzene-Oligoglycerol Conjugates. Angew Chem Int Ed Engl 2014; 53:9669-73. [DOI: 10.1002/anie.201403331] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 04/30/2014] [Indexed: 11/06/2022]
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30
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Nachtigall O, Kördel C, Urner LH, Haag R. Lichtgesteuertes Schalten von Azobenzol-Oligoglycerin-Konjugaten auf supramolekular funktionalisierten Oberflächen. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201403331] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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31
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Li M, Yan H, Teh C, Korzh V, Zhao Y. NIR-triggered drug release from switchable rotaxane-functionalized silica-covered Au nanorods. Chem Commun (Camb) 2014; 50:9745-8. [DOI: 10.1039/c4cc02966f] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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32
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Chen KY, Ivashenko O, Carroll GT, Robertus J, Kistemaker JCM, London G, Browne WR, Rudolf P, Feringa BL. Control of Surface Wettability Using Tripodal Light-Activated Molecular Motors. J Am Chem Soc 2014; 136:3219-24. [DOI: 10.1021/ja412110t] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Kuang-Yen Chen
- Centre
for Systems Chemistry,
Stratingh Institute for Chemistry and Zernike Institute for Advanced
Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Oleksii Ivashenko
- Centre
for Systems Chemistry,
Stratingh Institute for Chemistry and Zernike Institute for Advanced
Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Gregory T. Carroll
- Centre
for Systems Chemistry,
Stratingh Institute for Chemistry and Zernike Institute for Advanced
Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Jort Robertus
- Centre
for Systems Chemistry,
Stratingh Institute for Chemistry and Zernike Institute for Advanced
Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - 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, The Netherlands
| | - Gábor London
- Centre
for Systems Chemistry,
Stratingh Institute for Chemistry and Zernike Institute for Advanced
Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Wesley R. Browne
- Centre
for Systems Chemistry,
Stratingh Institute for Chemistry and Zernike Institute for Advanced
Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Petra Rudolf
- Centre
for Systems Chemistry,
Stratingh Institute for Chemistry and Zernike Institute for Advanced
Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - 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, The Netherlands
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33
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Holowka EP, Bhatia SK. Smart Drug Delivery Systems. Drug Deliv 2014. [DOI: 10.1007/978-1-4939-1998-7_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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34
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Jung U, Kubitschke J, Herges R, Magnussen O. Studies of the molecular switching of azobenzene-functionalized platform adlayers on Au(111) by chronoamperometry. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.06.123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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35
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Valley DT, Onstott M, Malyk S, Benderskii AV. Steric hindrance of photoswitching in self-assembled monolayers of azobenzene and alkane thiols. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:11623-11631. [PMID: 23924041 DOI: 10.1021/la402144g] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Surface-bound azobenzenes exhibit reversible photoswitching via trans-cis photoisomerization and have been proposed for a variety of applications such as photowritable optical media, liquid crystal displays, molecular electronics, and smart wetting surfaces. We report a novel synthetic route using simple protection chemistry to form azobenzene-functionalized SAMs on gold and present a mechanistic study of the molecular order, orientation, and conformation in these self-assembled monolayers (SAMs). We use vibrational sum-frequency generation (VSFG) to characterize their vibrational modes, molecular orientation, and photoisomerization kinetics. Trans-cis conformational change of azobenzene leads to the change in the orientation of the nitrile marker group detected by VSFG. Mixed SAMs of azobenzene and alkane thiols are used to investigate the steric hindrance effects. While 100% azobenzene SAMs do not exhibit photoisomerization due to tight packing, we observe reversible switching (>10 cycles) in mixed SAMs with only 34% and 50% of alkane thiol spacers.
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Affiliation(s)
- David T Valley
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
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36
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Yeung CL, Charlesworth S, Iqbal P, Bowen J, Preece JA, Mendes PM. Different formation kinetics and photoisomerization behavior of self-assembled monolayers of thiols and dithiolanes bearing azobenzene moieties. Phys Chem Chem Phys 2013; 15:11014-24. [PMID: 23712584 DOI: 10.1039/c3cp42104j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Self-assembled monolayers (SAMs) containing azobenzene moieties are very attractive for a wide range of applications, including molecular electronics and photonics, bio-interface engineering and sensoring. However, very little is known about the aggregation and photoswitching behavior that azobenzene units undergo during the SAM formation process. Here, we demonstrate that the formation of thiol-based SAMs containing azobenzenes (denoted as AzoSH) on gold surfaces is characterised by a two-step adsorption kinetics, while a three-step assembly process has been identified for dithiolane-based SAMs containing azobenzenes (denoted AzoSS). The H-aggregation on the AzoSS SAMs was found to be remarkably dependent on the time of self-assembly, with less aggregation as a function of time. While photoisomerization of the AzoSH was suppressed for all different assembly times, the reversible trans-cis photoisomerization of AzoSS SAMs formed over 24 hours was clearly observed upon alternating UV and Vis light irradiation. We contend that detailed information on formation kinetics and related optical properties is of crucial importance for elucidating the photoswitching capabilities of azobenzene-based SAMs.
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Affiliation(s)
- Chun L Yeung
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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37
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Affiliation(s)
- Bala Krishna Pathem
- California NanoSystems Institute,
- Department of Chemistry and Biochemistry, and
| | - Shelley A. Claridge
- California NanoSystems Institute,
- Department of Chemistry and Biochemistry, and
| | - Yue Bing Zheng
- California NanoSystems Institute,
- Department of Chemistry and Biochemistry, and
| | - Paul S. Weiss
- California NanoSystems Institute,
- Department of Chemistry and Biochemistry, and
- Department of Materials Science and Engineering, University of California, Los Angeles, California 90095;
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38
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Molecular motions in functional self-assembled nanostructures. Int J Mol Sci 2013; 14:2303-33. [PMID: 23348927 PMCID: PMC3587989 DOI: 10.3390/ijms14022303] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 01/11/2013] [Accepted: 01/11/2013] [Indexed: 02/01/2023] Open
Abstract
The construction of "smart" materials able to perform specific functions at the molecular scale through the application of various stimuli is highly attractive but still challenging. The most recent applications indicate that the outstanding flexibility of self-assembled architectures can be employed as a powerful tool for the development of innovative molecular devices, functional surfaces and smart nanomaterials. Structural flexibility of these materials is known to be conferred by weak intermolecular forces involved in self-assembly strategies. However, some fundamental mechanisms responsible for conformational lability remain unexplored. Furthermore, the role played by stronger bonds, such as coordination, ionic and covalent bonding, is sometimes neglected while they can be employed readily to produce mechanically robust but also chemically reversible structures. In this review, recent applications of structural flexibility and molecular motions in self-assembled nanostructures are discussed. Special focus is given to advanced materials exhibiting significant performance changes after an external stimulus is applied, such as light exposure, pH variation, heat treatment or electromagnetic field. The crucial role played by strong intra- and weak intermolecular interactions on structural lability and responsiveness is highlighted.
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39
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Zheng YB, Pathem BK, Hohman JN, Thomas JC, Kim M, Weiss PS. Photoresponsive molecules in well-defined nanoscale environments. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:302-312. [PMID: 22933316 DOI: 10.1002/adma.201201532] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 07/01/2012] [Indexed: 06/01/2023]
Abstract
Stimuli-responsive molecules are key building blocks of functional molecular materials and devices. These molecules can operate in a range of environments. A molecule's local environment will dictate its conformation, reactivity, and function; by controlling the local environment we can ultimately develop interfaces of individual molecules with the macroscopic environment. By isolating molecules in well-defined environments, we are able to obtain both accurate measurements and precise control. We exploit defect sites in self-assembled monolayers (SAMs) to direct the functional molecules into precise locations, providing a basis for the measurements and engineering of functional molecular systems. The structure and functional moieties of the SAM can be tuned to control not only the intermolecular interactions but also molecule-substrate interactions, resulting in extraction or control of desired molecular functions. Herein, we report our progress toward the assembly and measurements of photoresponsive molecules and their precise assemblies in SAM matrices.
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Affiliation(s)
- Yue Bing Zheng
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
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40
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Schramm A, Stroh C, Dössel K, Lukas M, Fischer M, Schramm F, Fuhr O, Löhneysen HV, Mayor M. Tripodal MIIIComplexes on Au(111) Surfaces: Towards Molecular “Lunar Modules”. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201200928] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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41
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Brete D, Przyrembel D, Eickhoff C, Carley R, Freyer W, Reuter K, Gahl C, Weinelt M. Mixed self-assembled monolayers of azobenzene photoswitches with trifluoromethyl and cyano end groups. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:394015. [PMID: 22964547 DOI: 10.1088/0953-8984/24/39/394015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Mixed self-assembled monolayers (SAMs) of alkanethiolates carrying azobenzene chromophores with either a trifluoromethyl or a cyano substituent have been studied. High-resolution x-ray photoelectron spectroscopy proves that the ratio of adsorbed molecules can be arbitrarily adjusted via the molar fractions in solution. As a function of these molar fractions core level shifts are observed which are attributed to local work-function changes. By simulating the electric dipole field distribution, the continuous core level shifts are ascribed to a homogeneous mixture of molecules with different end groups adsorbed on adjacent lattice sites. Near-edge x-ray absorption fine structure measurements reveal formation of well-ordered SAMs. Despite the difference in dipole moment of the end groups, the molecular tilt and twist angles are identical for both single-component SAMs and a 1:1 mixed SAM.
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Affiliation(s)
- Daniel Brete
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
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42
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Dworak L, Zastrow M, Zeyat G, Rück-Braun K, Wachtveitl J. Ultrafast dynamics of dithienylethenes differently linked to the surface of TiO2 nanoparticles. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:394007. [PMID: 22964261 DOI: 10.1088/0953-8984/24/39/394007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The photoinduced dynamics of a dithienylethene chromophore coupled to the surface of TiO(2) by either a tripodal linker or a carboxyl group was investigated with ultrafast transient absorption spectroscopy. The absence of electron transfer from the photoexcited tripodal dithienylethene chromophore demonstrates that the tripod efficiently uncouples the electronic systems of dithienylethene and TiO(2). Contrary to this situation, photoinduced electron transfer can compete with ultrafast intramolecular relaxation in the COOH-dithienylethene/TiO(2) coupled system. An electron transfer rate of 1.1 × 10(12) s(-1) can be extracted, which is considerably slower than the intramolecular relaxation rate of the dithienylethene (3.7 × 10(12) s(-1)). Consequently, the electron transfer reaction exhibits a low efficiency.
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Affiliation(s)
- Lars Dworak
- Institute of Physical and Theoretical Chemistry, Goethe-University, Max-von-Laue-Strasse 7, D-60438 Frankfurt/Main, Germany
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43
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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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44
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Darwish TA, Tong Y, James M, Hanley TL, Peng Q, Ye S. Characterizing the photoinduced switching process of a nitrospiropyran self-assembled monolayer using in situ sum frequency generation spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:13852-13860. [PMID: 22937910 DOI: 10.1021/la302204f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Sum frequency generation (SFG) vibrational spectroscopy is employed to investigate the reversible, photoinduced spiro→merocyanine isomerization of a self-assembled monolayer, the result of attachment of nitrospiropyran to a gold surface using a dithiolane anchoring group. The attachment of these molecular "alligator clips" to spiropyran molecules provide an easily accessible method to self-assemble a robust monolayer of spiropyran on a gold surface, which allows photoswitching of the spiropyran units. Probing the symmetric and antisymmetric stretching modes of the nitro group allows the determination of the structural orientation of the charged moiety with respect to the surface normal as well as the isomerization rates under photoinduced switching conditions. The photoisomerization of the spiropyran SAM on the gold surface is much faster than the rates of switching spiropyrans in a solid crystalline form, and the rate of thermal relaxation of the opened to closed form in this study is found to be on the same time scale as the relaxation of spiropyran when present in solutions with polar solvents.
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Affiliation(s)
- Tamim A Darwish
- Australian Nuclear Science and Technology Organisation (ANSTO), Kirrawee DC, NSW 2232, Australia.
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45
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Pathem BK, Zheng YB, Payton JL, Song TB, Yu BC, Tour JM, Yang Y, Jensen L, Weiss PS. Effect of Tether Conductivity on the Efficiency of Photoisomerization of Azobenzene-Functionalized Molecules on Au{111}. J Phys Chem Lett 2012; 3:2388-2394. [PMID: 26292120 DOI: 10.1021/jz300968m] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We establish the role of tether conductivity on the photoisomerization of azobenzene-functionalized molecules assembled as isolated single molecules in well-defined decanethiolate self-assembled monolayer matrices on Au{111}. We designed the molecules so as to tune the conductivity of the tethers that separate the functional moiety from the underlying Au substrate. By employing surface-enhanced Raman spectroscopy, time-course measurements of surfaces assembled with azobenzene functionalized with different tether conductivities were independently studied under constant UV light illumination. The decay constants from the analyses reveal that photoisomerization on the Au{111} surface is reduced when the conductivity of the tether is increased. Experimental results are compared with density functional theory calculations performed on single molecules attached to Au clusters.
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Affiliation(s)
| | | | - John L Payton
- ∥Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | | | - Byung-Chan Yu
- ⊥Department of Chemistry and The Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, United States
| | - James M Tour
- ⊥Department of Chemistry and The Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, United States
| | | | - Lasse Jensen
- ∥Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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46
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Kördel C, Setaro A, Bluemmel P, Popeney CS, Reich S, Haag R. Controlled reversible debundling of single-walled carbon nanotubes by photo-switchable dendritic surfactants. NANOSCALE 2012; 4:3029-3031. [PMID: 22504733 DOI: 10.1039/c2nr30305a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Stimulus responsive surfactants based on dendritic glycerol azobenzene conjugates were used to solubilize and debundle single-walled carbon nanotubes in aqueous media. Their debundling property as well as their reaggregation behavior upon irradiation with light was examined and light triggered reversible bundling and precipitation are shown.
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Affiliation(s)
- Christian Kördel
- Freie Universität Berlin, Institut für Chemie und Biochemie, Takustraße 3, 14195 Berlin, Germany
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47
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Tahri Z, Lepski R, Hsieh KY, Bendeif EE, Pillet S, Durand P, Woike T, Schaniel D. Properties of metastable linkage NO isomers in Na2[Fe(CN)5NO]·2H2O incorporated in mesopores of silica xerogels. Phys Chem Chem Phys 2012; 14:3775-81. [DOI: 10.1039/c2cp23607a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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48
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Bléger D, Ciesielski A, Samorì P, Hecht S. Photoswitching vertically oriented azobenzene self-assembled monolayers at the solid-liquid interface. Chemistry 2011; 16:14256-60. [PMID: 21108263 DOI: 10.1002/chem.201002834] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- David Bléger
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
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49
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Backus EHG, Kuiper JM, Engberts JBFN, Poolman B, Bonn M. Reversible Optical Control of Monolayers on Water through Photoswitchable Lipids. J Phys Chem B 2011; 115:2294-302. [DOI: 10.1021/jp1113619] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Ellen H. G. Backus
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Johanna M. Kuiper
- Departments of Biochemistry and Synthetic-Organic Chemistry, Stratingh and Zernike Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Jan B. F. N. Engberts
- Departments of Biochemistry and Synthetic-Organic Chemistry, Stratingh and Zernike Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Bert Poolman
- Departments of Biochemistry and Synthetic-Organic Chemistry, Stratingh and Zernike Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Mischa Bonn
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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50
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Kördel C, Popeney CS, Haag R. Photoresponsive amphiphiles based on azobenzene-dendritic glycerol conjugates show switchable transport behavior. Chem Commun (Camb) 2011; 47:6584-6. [DOI: 10.1039/c1cc11673h] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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