1
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Zhong Q, Jung J, Kohrs D, Kaczmarek LA, Ebeling D, Mollenhauer D, Wegner HA, Schirmeisen A. Deciphering the Mechanism of On-Surface Dehydrogenative C-C Coupling Reactions. J Am Chem Soc 2024; 146:1849-1859. [PMID: 38226612 DOI: 10.1021/jacs.3c05233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
On-surface synthesis has proven to be a powerful approach for fabricating various low-dimensional covalent nanostructures with atomic precision that could be challenging for conventional solution chemistry. Dehydrogenative Caryl-Caryl coupling is one of the most popular on-surface reactions, of which the mechanisms, however, have not been well understood due to the lack of microscopic insights into the intermediates that are fleetingly existing under harsh reaction conditions. Here, we bypass the most energy-demanding initiation step to generate and capture some of the intermediates at room temperature (RT) via the cyclodehydrobromination of 1-bromo-8-phenylnaphthalene on a Cu(111) surface. Bond-level scanning probe imaging and manipulation in combination with DFT calculations allow for the identification of chemisorbed radicals, cyclized intermediates, and dehydrogenated products. These intermediates correspond to three main reaction steps, namely, debromination, cyclization (radical addition), and H elimination. H elimination is the rate-determining step as evidenced by the predominant cyclized intermediates. Furthermore, we reveal a long-overlooked pathway of dehydrogenation, namely, atomic hydrogen-catalyzed H shift and elimination, based on the observation of intermediates for H shift and superhydrogenation and the proof of a self-amplifying effect of the reaction. This pathway is further corroborated by comprehensive theoretical analysis on the reaction thermodynamics and kinetics.
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Affiliation(s)
- Qigang Zhong
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen 35392, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Giessen 35392, Germany
- Institute of Functional Nano & Soft Materials, Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, P. R. China
| | - Jannis Jung
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Giessen 35392, Germany
- Institute of Physical Chemistry, Justus Liebig University Giessen, Giessen 35392, Germany
| | - Daniel Kohrs
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Giessen 35392, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen 35392, Germany
| | - L Alix Kaczmarek
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Giessen 35392, Germany
- Institute of Physical Chemistry, Justus Liebig University Giessen, Giessen 35392, Germany
| | - Daniel Ebeling
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen 35392, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Giessen 35392, Germany
| | - Doreen Mollenhauer
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Giessen 35392, Germany
- Institute of Physical Chemistry, Justus Liebig University Giessen, Giessen 35392, Germany
| | - Hermann A Wegner
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Giessen 35392, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen 35392, Germany
| | - André Schirmeisen
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen 35392, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Giessen 35392, Germany
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2
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Zhong Q, Mardyukov A, Solel E, Ebeling D, Schirmeisen A, Schreiner PR. On-Surface Synthesis and Real-Space Visualization of Aromatic P 3 N 3. Angew Chem Int Ed Engl 2023; 62:e202310121. [PMID: 37702299 DOI: 10.1002/anie.202310121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 09/14/2023]
Abstract
On-surface synthesis is at the verge of emerging as the method of choice for the generation and visualization of unstable or unconventional molecules, which could not be obtained via traditional synthetic methods. A case in point is the on-surface synthesis of the structurally elusive cyclotriphosphazene (P3 N3 ), an inorganic aromatic analogue of benzene. Here, we report the preparation of this fleetingly existing species on Cu(111) and Au(111) surfaces at 5.2 K through molecular manipulation with unprecedented precision, i.e., voltage pulse-induced sextuple dechlorination of an ultra-small (about 6 Å) hexachlorophosphazene P3 N3 Cl6 precursor by the tip of a scanning probe microscope. Real-space atomic-level imaging of cyclotriphosphazene reveals its planar D3h -symmetric ring structure. Furthermore, this demasking strategy has been expanded to generate cyclotriphosphazene from a hexaazide precursor P3 N21 via a different stimulation method (photolysis) for complementary measurements by matrix isolation infrared and ultraviolet spectroscopy.
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Affiliation(s)
- Qigang Zhong
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
| | - Artur Mardyukov
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Ephrath Solel
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Daniel Ebeling
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
| | - André Schirmeisen
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
| | - Peter R Schreiner
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen, Germany
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3
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Klein BP, Ihle A, Kachel SR, Ruppenthal L, Hall SJ, Sattler L, Weber SM, Herritsch J, Jaegermann A, Ebeling D, Maurer RJ, Hilt G, Tonner-Zech R, Schirmeisen A, Gottfried JM. Topological Stone-Wales Defects Enhance Bonding and Electronic Coupling at the Graphene/Metal Interface. ACS Nano 2022; 16:11979-11987. [PMID: 35916359 DOI: 10.1021/acsnano.2c01952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Defects play a critical role for the functionality and performance of materials, but the understanding of the related effects is often lacking, because the typically low concentrations of defects make them difficult to study. A prominent case is the topological defects in two-dimensional materials such as graphene. The performance of graphene-based (opto-)electronic devices depends critically on the properties of the graphene/metal interfaces at the contacting electrodes. The question of how these interface properties depend on the ubiquitous topological defects in graphene is of high practical relevance, but could not be answered so far. Here, we focus on the prototypical Stone-Wales (S-W) topological defect and combine theoretical analysis with experimental investigations of molecular model systems. We show that the embedded defects undergo enhanced bonding and electron transfer with a copper surface, compared to regular graphene. These findings are experimentally corroborated using molecular models, where azupyrene mimics the S-W defect, while its isomer pyrene represents the ideal graphene structure. Experimental interaction energies, electronic-structure analysis, and adsorption distance differences confirm the defect-controlled bonding quantitatively. Our study reveals the important role of defects for the electronic coupling at graphene/metal interfaces and suggests that topological defect engineering can be used for performance control.
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Affiliation(s)
- Benedikt P Klein
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße. 4, 35032 Marburg, Germany
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Alexander Ihle
- Institut für Angewandte Physik, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Stefan R Kachel
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße. 4, 35032 Marburg, Germany
| | - Lukas Ruppenthal
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße. 4, 35032 Marburg, Germany
| | | | - Lars Sattler
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße. 9-11, 26111 Oldenburg, Germany
| | - Sebastian M Weber
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße. 9-11, 26111 Oldenburg, Germany
| | - Jan Herritsch
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße. 4, 35032 Marburg, Germany
| | - Andrea Jaegermann
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße. 4, 35032 Marburg, Germany
| | - Daniel Ebeling
- Institut für Angewandte Physik, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | | | - Gerhard Hilt
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße. 9-11, 26111 Oldenburg, Germany
| | - Ralf Tonner-Zech
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße. 4, 35032 Marburg, Germany
| | - André Schirmeisen
- Institut für Angewandte Physik, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - J Michael Gottfried
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße. 4, 35032 Marburg, Germany
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4
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Zhong Q, Niu K, Chen L, Zhang H, Ebeling D, Björk J, Müllen K, Schirmeisen A, Chi L. Substrate-Modulated Synthesis of Metal-Organic Hybrids by Tunable Multiple Aryl-Metal Bonds. J Am Chem Soc 2022; 144:8214-8222. [PMID: 35442656 DOI: 10.1021/jacs.2c01338] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Assembly of semiconducting organic molecules with multiple aryl-metal covalent bonds into stable one- and two-dimensional (1D and 2D) metal-organic frameworks represents a promising route to the integration of single-molecule electronics in terms of structural robustness and charge transport efficiency. Although various metastable organometallic frameworks have been constructed by the extensive use of single aryl-metal bonds, it remains a great challenge to embed multiple aryl-metal bonds into these structures due to inadequate knowledge of harnessing such complex bonding motifs. Here, we demonstrate the substrate-modulated synthesis of 1D and 2D metal-organic hybrids (MOHs) with the organic building blocks (perylene) interlinked solely with multiple aryl-metal bonds via the stepwise thermal dehalogenation of 3,4,9,10-tetrabromo-1,6,7,12-tetrachloroperylene and subsequent metal-organic connection on metal surfaces. More importantly, the conversion from 1D to 2D MOHs is completely impeded on Au(111) but dominant on Ag(111). We comprehensively study the distinct reaction pathways on the two surfaces by visually tracking the structural evolution of the MOHs with high-resolution scanning tunneling and noncontact atomic force microscopy, supported by first-principles density functional theory calculations. The substrate-dependent structural control of the MOHs is attributed to the variation of the M-X (M = Au, Ag; X = C, Cl) bond strength regulated by the nature of the metal species.
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Affiliation(s)
- Qigang Zhong
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials, Soochow University, 215123 Suzhou, China.,Institute of Applied Physics, Justus-Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Kaifeng Niu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials, Soochow University, 215123 Suzhou, China.,Department of Physics, Chemistry and Biology, IFM, Linköping University, 58183 Linköping, Sweden
| | - Long Chen
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Haiming Zhang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials, Soochow University, 215123 Suzhou, China
| | - Daniel Ebeling
- Institute of Applied Physics, Justus-Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Jonas Björk
- Department of Physics, Chemistry and Biology, IFM, Linköping University, 58183 Linköping, Sweden
| | - Klaus Müllen
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany.,Institute of Physical Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - André Schirmeisen
- Institute of Applied Physics, Justus-Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Lifeng Chi
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials, Soochow University, 215123 Suzhou, China
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5
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Martin-Jimenez D, Ruppert MG, Ihle A, Ahles S, Wegner HA, Schirmeisen A, Ebeling D. Chemical bond imaging using torsional and flexural higher eigenmodes of qPlus sensors. Nanoscale 2022; 14:5329-5339. [PMID: 35348167 DOI: 10.1039/d2nr01062c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Non-contact atomic force microscopy (AFM) with CO-functionalized tips allows visualization of the chemical structure of adsorbed molecules and identify individual inter- and intramolecular bonds. This technique enables in-depth studies of on-surface reactions and self-assembly processes. Herein, we analyze the suitability of qPlus sensors, which are commonly used for such studies, for the application of modern multifrequency AFM techniques. Two different qPlus sensors were tested for submolecular resolution imaging via actuating torsional and flexural higher eigenmodes and via bimodal AFM. The torsional eigenmode of one of our sensors is perfectly suited for performing lateral force microscopy (LFM) with single bond resolution. The obtained LFM images agree well with images from the literature, which were scanned with customized qPlus sensors that were specifically designed for LFM. The advantage of using a torsional eigenmode is that the same molecule can be imaged either with a vertically or laterally oscillating tip without replacing the sensor simply by actuating a different eigenmode. Submolecular resolution is also achieved by actuating the 2nd flexural eigenmode of our second sensor. In this case, we observe particular contrast features that only appear in the AFM images of the 2nd flexural eigenmode but not for the fundamental eigenmode. With complementary laser Doppler vibrometry measurements and AFM simulations we can rationalize that these contrast features are caused by a diagonal (i.e. in-phase vertical and lateral) oscillation of the AFM tip.
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Affiliation(s)
- Daniel Martin-Jimenez
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany.
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany
| | | | - Alexander Ihle
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany.
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany
| | - Sebastian Ahles
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, Giessen 35392, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany
| | - Hermann A Wegner
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, Giessen 35392, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany
| | - André Schirmeisen
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany.
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany
| | - Daniel Ebeling
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany.
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany
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6
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Ruppert MG, Martin-Jimenez D, Yong YK, Ihle A, Schirmeisen A, Fleming AJ, Ebeling D. Experimental analysis of tip vibrations at higher eigenmodes of QPlus sensors for atomic force microscopy. Nanotechnology 2022; 33:185503. [PMID: 34972093 DOI: 10.1088/1361-6528/ac4759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/30/2021] [Indexed: 06/14/2023]
Abstract
QPlus sensors are non-contact atomic force microscope probes constructed from a quartz tuning fork and a tungsten wire with an electrochemically etched tip. These probes are self-sensing and offer an atomic-scale spatial resolution. Therefore, qPlus sensors are routinely used to visualize the chemical structure of adsorbed organic molecules via the so-called bond imaging technique. This is achieved by functionalizing the AFM tip with a single CO molecule and exciting the sensor at the first vertical cantilever resonance mode. Recent work using higher-order resonance modes has also resolved the chemical structure of single organic molecules. However, in these experiments, the image contrast can differ significantly from the conventional bond imaging contrast, which was suspected to be caused by unknown vibrations of the tip. This work investigates the source of these artefacts by using a combination of mechanical simulation and laser vibrometry to characterize a range of sensors with different tip wire geometries. The results show that increased tip mass and length cause increased torsional rotation of the tuning fork beam due to the off-center mounting of the tip wire, and increased flexural vibration of the tip. These undesirable motions cause lateral deflection of the probe tip as it approaches the sample, which is rationalized to be the cause of the different image contrast. The results also provide a guide for future probe development to reduce these issues.
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Affiliation(s)
- Michael G Ruppert
- School of Engineering, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Daniel Martin-Jimenez
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany
| | - Yuen K Yong
- School of Engineering, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Alexander Ihle
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany
| | - André Schirmeisen
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany
| | - Andrew J Fleming
- School of Engineering, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Daniel Ebeling
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany
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7
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Zhong Q, Ihle A, Ahles S, Wegner HA, Schirmeisen A, Ebeling D. Constructing covalent organic nanoarchitectures molecule by molecule via scanning probe manipulation. Nat Chem 2021; 13:1133-1139. [PMID: 34475530 PMCID: PMC8550974 DOI: 10.1038/s41557-021-00773-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/12/2021] [Indexed: 11/09/2022]
Abstract
Constructing low-dimensional covalent assemblies with tailored size and connectivity is challenging yet often key for applications in molecular electronics where optical and electronic properties of the quantum materials are highly structure dependent. We present a versatile approach for building such structures block by block on bilayer sodium chloride (NaCl) films on Cu(111) with the tip of an atomic force microscope, while tracking the structural changes with single-bond resolution. Covalent homo-dimers in cis and trans configurations and homo-/hetero-trimers were selectively synthesized by a sequence of dehalogenation, translational manipulation and intermolecular coupling of halogenated precursors. Further demonstrations of structural build-up include complex bonding motifs, like carbon–iodine–carbon bonds and fused carbon pentagons. This work paves the way for synthesizing elusive covalent nanoarchitectures, studying structural modifications and revealing pathways of intermolecular reactions. ![]()
Tailoring the size and connectivity of organic nanostructures is challenging but is often key in molecular electronics for tuning the properties of the quantum materials. Now an approach has been developed for building low-dimensional covalent architectures block by block on a surface by highly selective tip-induced intermolecular reactions.
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Affiliation(s)
- Qigang Zhong
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany. .,Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany.
| | - Alexander Ihle
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany.,Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany
| | - Sebastian Ahles
- Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany.,Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Hermann A Wegner
- Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany.,Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Andre Schirmeisen
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany. .,Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany.
| | - Daniel Ebeling
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany. .,Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany.
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8
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Tschakert J, Zhong Q, Martin-Jimenez D, Carracedo-Cosme J, Romero-Muñiz C, Henkel P, Schlöder T, Ahles S, Mollenhauer D, Wegner HA, Pou P, Pérez R, Schirmeisen A, Ebeling D. Surface-controlled reversal of the selectivity of halogen bonds. Nat Commun 2020; 11:5630. [PMID: 33159060 PMCID: PMC7648107 DOI: 10.1038/s41467-020-19379-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 10/01/2020] [Indexed: 11/08/2022] Open
Abstract
Intermolecular halogen bonds are ideally suited for designing new molecular assemblies because of their strong directionality and the possibility of tuning the interactions by using different types of halogens or molecular moieties. Due to these unique properties of the halogen bonds, numerous areas of application have recently been identified and are still emerging. Here, we present an approach for controlling the 2D self-assembly process of organic molecules by adsorption to reactive vs. inert metal surfaces. Therewith, the order of halogen bond strengths that is known from gas phase or liquids can be reversed. Our approach relies on adjusting the molecular charge distribution, i.e., the σ-hole, by molecule-substrate interactions. The polarizability of the halogen and the reactiveness of the metal substrate are serving as control parameters. Our results establish the surface as a control knob for tuning molecular assemblies by reversing the selectivity of bonding sites, which is interesting for future applications.
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Affiliation(s)
- Jalmar Tschakert
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Qigang Zhong
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Daniel Martin-Jimenez
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Jaime Carracedo-Cosme
- Quasar Science Resources S.L., Camino de las Ceudas 2, E-28232, Las Rozas de Madrid, Spain
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049, Madrid, Spain
| | - Carlos Romero-Muñiz
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049, Madrid, Spain
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Ctra. Utrera Km. 1, E-41013, Seville, Spain
| | - Pascal Henkel
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
- Institute of Physical Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Tobias Schlöder
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
- Institute of Physical Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Sebastian Ahles
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Doreen Mollenhauer
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
- Institute of Physical Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Hermann A Wegner
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Pablo Pou
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049, Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049, Madrid, Spain
| | - Rubén Pérez
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049, Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049, Madrid, Spain
| | - André Schirmeisen
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Daniel Ebeling
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany.
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany.
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9
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Fan Q, Martin-Jimenez D, Werner S, Ebeling D, Koehler T, Vollgraff T, Sundermeyer J, Hieringer W, Schirmeisen A, Gottfried JM. On-Surface Synthesis and Characterization of a Cycloarene: C108 Graphene Ring. J Am Chem Soc 2019; 142:894-899. [DOI: 10.1021/jacs.9b10151] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Qitang Fan
- Department of Chemistry and Material Sciences Center (WZMW), Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg, Germany
| | - Daniel Martin-Jimenez
- Institute of Applied Physics (IAP) and Center for Materials Research (LaMa), Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Simon Werner
- Department of Chemistry and Material Sciences Center (WZMW), Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg, Germany
| | - Daniel Ebeling
- Institute of Applied Physics (IAP) and Center for Materials Research (LaMa), Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Tabea Koehler
- Department of Chemistry and Material Sciences Center (WZMW), Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg, Germany
| | - Tobias Vollgraff
- Department of Chemistry and Material Sciences Center (WZMW), Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg, Germany
| | - Jörg Sundermeyer
- Department of Chemistry and Material Sciences Center (WZMW), Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg, Germany
| | - Wolfgang Hieringer
- Theoretical Chemistry and Computer-Chemistry-Center for Molecular Materials (ICMM), Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - André Schirmeisen
- Institute of Applied Physics (IAP) and Center for Materials Research (LaMa), Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - J. Michael Gottfried
- Department of Chemistry and Material Sciences Center (WZMW), Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg, Germany
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10
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Fan Q, Martin-Jimenez D, Ebeling D, Krug CK, Brechmann L, Kohlmeyer C, Hilt G, Hieringer W, Schirmeisen A, Gottfried JM. Nanoribbons with Nonalternant Topology from Fusion of Polyazulene: Carbon Allotropes beyond Graphene. J Am Chem Soc 2019; 141:17713-17720. [DOI: 10.1021/jacs.9b08060] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Qitang Fan
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein-Straße 4, Marburg 35032, Germany
| | | | | | - Claudio K. Krug
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein-Straße 4, Marburg 35032, Germany
| | - Lea Brechmann
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein-Straße 4, Marburg 35032, Germany
| | - Corinna Kohlmeyer
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl-von-Ossietzky-Straße 9-11, Oldenburg 26111, Germany
| | - Gerhard Hilt
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl-von-Ossietzky-Straße 9-11, Oldenburg 26111, Germany
| | - Wolfgang Hieringer
- Theoretical Chemistry and Interdisciplinary Center for Molecular Materials (ICMM), Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, Erlangen 91058, Germany
| | | | - J. Michael Gottfried
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein-Straße 4, Marburg 35032, Germany
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11
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Martin-Jimenez D, Ahles S, Mollenhauer D, Wegner HA, Schirmeisen A, Ebeling D. Bond-Level Imaging of the 3D Conformation of Adsorbed Organic Molecules Using Atomic Force Microscopy with Simultaneous Tunneling Feedback. Phys Rev Lett 2019; 122:196101. [PMID: 31144947 DOI: 10.1103/physrevlett.122.196101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Indexed: 06/09/2023]
Abstract
The chemical structure and orientation of molecules on surfaces can be visualized using low temperature atomic force microscopy with CO-functionalized tips. Conventionally, this is done in constant-height mode by measuring the frequency shift of the oscillating force sensor. However, this method is unsuitable for analyzing 3D objects. We are using the tunneling current to track the topography while simultaneously obtaining submolecular resolution from the frequency shift signal. Thereby, the conformation of 3D molecules and the adsorption sites on the atomic lattice can be reliably determined.
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Affiliation(s)
- Daniel Martin-Jimenez
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Sebastian Ahles
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Doreen Mollenhauer
- Institute of Physical Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Hermann A Wegner
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Andre Schirmeisen
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Daniel Ebeling
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
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12
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Zhong Q, Hu Y, Niu K, Zhang H, Yang B, Ebeling D, Tschakert J, Cheng T, Schirmeisen A, Narita A, Müllen K, Chi L. Benzo-Fused Periacenes or Double Helicenes? Different Cyclodehydrogenation Pathways on Surface and in Solution. J Am Chem Soc 2019; 141:7399-7406. [PMID: 31016976 PMCID: PMC6727374 DOI: 10.1021/jacs.9b01267] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Controlling the regioselectivity of C-H activation in unimolecular reactions is of great significance for the rational synthesis of functional graphene nanostructures, which are called nanographenes. Here, we demonstrate that the adsorption of tetranaphthyl- p-terphenyl precursors on metal surfaces can completely change the cyclodehydrogenation route and lead to obtaining planar benzo-fused perihexacenes rather than double [7]helicenes during solution synthesis. The course of the on-surface planarization reactions is monitored using scanning probe microscopy, which unambiguously reveals the formation of dibenzoperihexacenes and the structures of reaction intermediates. The regioselective planarization can be attributed to the flattened adsorption geometries and the reduced flexibility of the precursors on the surfaces, in addition to the different mechanism of the on-surface cyclodehydrogenation from that of the solution counterpart. We have further achieved the on-surface synthesis of dibenzoperioctacene by employing a tetra-anthryl- p-terphenyl precursor. The energy gaps of the new nanographenes are measured to be approximately 2.1 eV (dibenzoperihexacene) and 1.3 eV (dibenzoperioctacene) on a Au(111) surface. Our findings shed new light on the regioselectivity in cyclodehydrogenation reactions, which will be important for exploring the synthesis of unprecedented nanographenes.
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Affiliation(s)
- Qigang Zhong
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Joint International Research Laboratory of Carbon-Based Functional Materials and Devices , Soochow University , Suzhou 215123 , China.,Institute of Applied Physics , Justus-Liebig University , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
| | - Yunbin Hu
- Max Planck Institute for Polymer Research , 55128 Mainz , Germany.,Department of Organic and Polymer Chemistry, College of Chemistry and Chemical Engineering , Central South University , Changsha , Hunan 410083 , China
| | - Kaifeng Niu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Joint International Research Laboratory of Carbon-Based Functional Materials and Devices , Soochow University , Suzhou 215123 , China
| | - Haiming Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Joint International Research Laboratory of Carbon-Based Functional Materials and Devices , Soochow University , Suzhou 215123 , China
| | - Biao Yang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Joint International Research Laboratory of Carbon-Based Functional Materials and Devices , Soochow University , Suzhou 215123 , China
| | - Daniel Ebeling
- Institute of Applied Physics , Justus-Liebig University , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
| | - Jalmar Tschakert
- Institute of Applied Physics , Justus-Liebig University , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
| | - Tao Cheng
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Joint International Research Laboratory of Carbon-Based Functional Materials and Devices , Soochow University , Suzhou 215123 , China
| | - André Schirmeisen
- Institute of Applied Physics , Justus-Liebig University , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
| | - Akimitsu Narita
- Max Planck Institute for Polymer Research , 55128 Mainz , Germany.,Organic and Carbon Nanomaterials Unit , Okinawa Institute of Science and Technology Graduate University , Okinawa 904-0495 , Japan
| | - Klaus Müllen
- Max Planck Institute for Polymer Research , 55128 Mainz , Germany.,Institute of Physical Chemistry , Johannes Gutenberg University Mainz , Duesbergweg 10-14 , 55128 Mainz , Germany
| | - Lifeng Chi
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Joint International Research Laboratory of Carbon-Based Functional Materials and Devices , Soochow University , Suzhou 215123 , China
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13
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Ebeling D, Zhong Q, Schlöder T, Tschakert J, Henkel P, Ahles S, Chi L, Mollenhauer D, Wegner HA, Schirmeisen A. Adsorption Structure of Mono- and Diradicals on a Cu(111) Surface: Chemoselective Dehalogenation of 4-Bromo-3″-iodo- p-terphenyl. ACS Nano 2019; 13:324-336. [PMID: 30550265 DOI: 10.1021/acsnano.8b06283] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Selectivity is a key parameter for building customized organic nanostructures via bottom-up approaches. Therefore, strategies are needed that allow connecting molecular entities at a specific stage of the assembly process in a chemoselective manner. Studying the mechanisms of such reactions is the key to apply these transformations for the buildup of organic nanostructures on surfaces. Especially, the knowledge about the precise adsorption geometry of intermediates at different stages during the reaction process and their interactions with surface atoms or adatoms is of fundamental importance, since often catalytic processes are involved. We show the selective dehalogenation of 4-bromo-3″-iodo- p-terphenyl on the Cu(111) surface using bond imaging atomic force microscopy with CO-functionalized tips. The deiodination and debromination reactions are triggered either by heating or by locally applying voltage pulses with the tip. We observed a strong hierarchical behavior of the dehalogenation with respect to temperature and voltage. In connection with first-principles simulations we can determine the orientation and position of the pristine molecules as well as adsorbed mono/diradicals and the halogens. We find that the isolated radicals are chemisorbed to Cu(111) top sites, which are lifted by 16 pm ( meta-position) and 32 pm ( para-position) from the Cu surface plane. This leads to a strongly twisted and bent 3D adsorption structure. After heating, different types of dimers are observed whose molecules are either bound to surface atoms or connected via Cu adatoms. Such knowledge about the intermediate geometry and its interaction with the surface will open the way to rationally design syntheses on surfaces.
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Affiliation(s)
- Daniel Ebeling
- Institute of Applied Physics , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
- Center for Materials Research (LaMa) , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
| | - Qigang Zhong
- Institute of Applied Physics , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
- Institute of Functional Nano & Soft Materials (FUNSOM) , Soochow University , 215123 Suzhou , People's Republic of China
| | - Tobias Schlöder
- Institute of Physical Chemistry , Justus Liebig University Giessen , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Jalmar Tschakert
- Institute of Applied Physics , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
- Center for Materials Research (LaMa) , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
| | - Pascal Henkel
- Center for Materials Research (LaMa) , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
- Institute of Physical Chemistry , Justus Liebig University Giessen , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Sebastian Ahles
- Center for Materials Research (LaMa) , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
- Institute of Organic Chemistry , Justus Liebig University Giessen , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Lifeng Chi
- Institute of Functional Nano & Soft Materials (FUNSOM) , Soochow University , 215123 Suzhou , People's Republic of China
| | - Doreen Mollenhauer
- Center for Materials Research (LaMa) , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
- Institute of Physical Chemistry , Justus Liebig University Giessen , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Hermann A Wegner
- Center for Materials Research (LaMa) , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
- Institute of Organic Chemistry , Justus Liebig University Giessen , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - André Schirmeisen
- Institute of Applied Physics , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
- Center for Materials Research (LaMa) , Justus Liebig University Giessen , Heinrich-Buff-Ring 16 , 35392 Giessen , Germany
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14
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Zhong Q, Ebeling D, Tschakert J, Gao Y, Bao D, Du S, Li C, Chi L, Schirmeisen A. Symmetry breakdown of 4,4″-diamino-p-terphenyl on a Cu(111) surface by lattice mismatch. Nat Commun 2018; 9:3277. [PMID: 30115915 PMCID: PMC6095862 DOI: 10.1038/s41467-018-05719-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 07/24/2018] [Indexed: 11/13/2022] Open
Abstract
Site-selective functionalization of only one of two identical chemical groups within one molecule is highly challenging, which hinders the production of complex organic macromolecules. Here we demonstrate that adsorption of 4,4″-diamino-p-terphenyl on a metal surface leads to a dissymmetric binding affinity. With low temperature atomic force microscopy, using CO-tip functionalization, we reveal the asymmetric adsorption geometries of 4,4″-diamino-p-terphenyl on Cu(111), while on Au(111) the symmetry is retained. This symmetry breaking on Cu(111) is caused by a lattice mismatch and interactions with the subsurface atomic layer. The dissymmetry results in a change of the binding affinity of one of the amine groups, leading to a non-stationary behavior under the influence of the scanning tip. Finally, we exploit this dissymmetric binding affinity for on-surface self-assembly with 4,4″-diamino-p-terphenyl for side-preferential attachment of 2-triphenylenecarbaldehyde. Our findings provide a new route towards surface-induced dissymmetric activation of a symmetric compound. In a symmetric molecule with identical functional groups, selective activation of only one site is challenging. Here, the authors show that 4,4″-diamino-p-terphenyl adsorbs asymmetrically to a metal surface, leading to a change in binding affinity of one of its amine groups.
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Affiliation(s)
- Qigang Zhong
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, 215123, P. R. China
| | - Daniel Ebeling
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany.
| | - Jalmar Tschakert
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Yixuan Gao
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Deliang Bao
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Shixuan Du
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
| | - Chen Li
- School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan, 523808, P. R. China
| | - Lifeng Chi
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, 215123, P. R. China.
| | - André Schirmeisen
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
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15
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Ebeling D, Šekutor M, Stiefermann M, Tschakert J, Dahl JEP, Carlson RMK, Schirmeisen A, Schreiner PR. Assigning the absolute configuration of single aliphatic molecules by visual inspection. Nat Commun 2018; 9:2420. [PMID: 29925833 PMCID: PMC6010418 DOI: 10.1038/s41467-018-04843-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 05/30/2018] [Indexed: 12/23/2022] Open
Abstract
Deciphering absolute configuration of a single molecule by direct visual inspection is the next step in compound identification, with far-reaching implications for medicinal chemistry, pharmacology, and natural product synthesis. We demonstrate the feasibility of this approach utilizing low temperature atomic force microscopy (AFM) with a CO-functionalized tip to determine the absolute configuration and orientation of a single, adsorbed [123]tetramantane molecule, the smallest chiral diamondoid. We differentiate between single enantiomers on Cu(111) by direct visual inspection, and furthermore identify molecular dimers and molecular clusters. The experimental results are confirmed by a computational study that allowed quantification of the corresponding intermolecular interactions. The unique toolset of absolute configuration determination combined with AFM tip manipulation opens a route for studying molecular nucleation, including chirality-driven assembly or reaction mechanisms.
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Affiliation(s)
- Daniel Ebeling
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany.
| | - Marina Šekutor
- Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany.
| | - Marvin Stiefermann
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Jalmar Tschakert
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Jeremy E P Dahl
- Stanford Institute for Materials and Energy Sciences, Stanford, CA, 94305, USA
| | - Robert M K Carlson
- Stanford Institute for Materials and Energy Sciences, Stanford, CA, 94305, USA
| | - André Schirmeisen
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany.
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany.
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16
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Fan Q, Werner S, Tschakert J, Ebeling D, Schirmeisen A, Hilt G, Hieringer W, Gottfried JM. Precise Monoselective Aromatic C-H Bond Activation by Chemisorption of Meta-Aryne on a Metal Surface. J Am Chem Soc 2018; 140:7526-7532. [PMID: 29750508 DOI: 10.1021/jacs.8b01658] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aromatic C-H bond activation has attracted much attention due to its versatile applications in the synthesis of aryl-containing chemicals. The major challenge lies in the minimization of the activation barrier and maximization of the regioselectivity. Here, we report the highly selective activation of the central aromatic C-H bond in meta-aryne species anchored to a copper surface, which catalyzes the C-H bond dissociation. Two prototype molecules, i.e., 4',6'-dibromo- meta-terphenyl and 3',5'-dibromo- ortho-terphenyl, have been employed to perform C-C coupling reactions on Cu(111). The chemical structures of the resulting products have been clarified by a combination of scanning tunneling microscopy and noncontact atomic force microscopy. Both methods demonstrate a remarkable weakening of the targeted C-H bond. Density functional theory calculations reveal that this efficient C-H activation stems from the extraordinary chemisorption of the meta-aryne on the Cu(111) surface, resulting in the close proximity of the targeted C-H group to the Cu(111) surface and the absence of planarity of the phenyl ring. These effects lead to a lowering of the C-H dissociation barrier from 1.80 to 1.12 eV, in agreement with the experimental data.
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Affiliation(s)
- Qitang Fan
- Department of Chemistry , Philipps University Marburg , Hans-Meerwein-Straße 4 , 35037 Marburg , Germany
| | - Simon Werner
- Department of Chemistry , Philipps University Marburg , Hans-Meerwein-Straße 4 , 35037 Marburg , Germany
| | - Jalmar Tschakert
- Institute of Applied Physics (IAP) , Justus Liebig University Gießen , Heinrich-Buff-Ring 16 , 35392 Gießen , Germany
| | - Daniel Ebeling
- Institute of Applied Physics (IAP) , Justus Liebig University Gießen , Heinrich-Buff-Ring 16 , 35392 Gießen , Germany
| | - André Schirmeisen
- Institute of Applied Physics (IAP) , Justus Liebig University Gießen , Heinrich-Buff-Ring 16 , 35392 Gießen , Germany
| | - Gerhard Hilt
- Institute of Chemistry , Carl von Ossietzky University Oldenburg , Carl-von-Ossietzky-Straße 9-11 , 26111 Oldenburg , Germany
| | - Wolfgang Hieringer
- Theoretical Chemistry and Interdisciplinary Center for Molecular Materials (ICMM), Department of Chemistry and Pharmacy , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , 91058 Erlangen , Germany
| | - J Michael Gottfried
- Department of Chemistry , Philipps University Marburg , Hans-Meerwein-Straße 4 , 35037 Marburg , Germany
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17
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Li Q, Yang B, Björk J, Zhong Q, Ju H, Zhang J, Cao N, Shi Z, Zhang H, Ebeling D, Schirmeisen A, Zhu J, Chi L. Hierarchical Dehydrogenation Reactions on a Copper Surface. J Am Chem Soc 2018. [DOI: 10.1021/jacs.7b12278] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Qing Li
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
| | - Biao Yang
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
| | - Jonas Björk
- Department of Physics, Chemistry and Biology, IFM, Linköping University, 58183 Linköping, Sweden
| | - Qigang Zhong
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring, 16, 35392 Giessen, Germany
| | - Huanxin Ju
- National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Junjie Zhang
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
| | - Nan Cao
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
| | - Ziliang Shi
- The Center for Soft Condensed Matter Physics & Interdisciplinary Research, Department of Physics, Soochow University, Suzhou 215006, China
| | - Haiming Zhang
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
| | - Daniel Ebeling
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring, 16, 35392 Giessen, Germany
| | - Andre Schirmeisen
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring, 16, 35392 Giessen, Germany
| | - Junfa Zhu
- National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Lifeng Chi
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
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18
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Ebeling D, Šekutor M, Stiefermann M, Tschakert J, Dahl JEP, Carlson RMK, Schirmeisen A, Schreiner PR. London Dispersion Directs On-Surface Self-Assembly of [121]Tetramantane Molecules. ACS Nano 2017; 11:9459-9466. [PMID: 28846392 DOI: 10.1021/acsnano.7b05204] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
London dispersion (LD) acts between all atoms and molecules in nature, but the role of LD interactions in the self-assembly of molecular layers is still poorly understood. In this study, direct visualization of single molecules using atomic force microscopy with CO-functionalized tips revealed the exact adsorption structures of bulky and highly polarizable [121]tetramantane molecules on Au(111) and Cu(111) surfaces. We determined the absolute molecular orientations of the completely sp3-hybridized tetramantanes on metal surfaces. Moreover, we demonstrate how LD drives this on-surface self-assembly of [121]tetramantane hydrocarbons, resulting in the formation of a highly ordered 2D lattice. Our experimental findings were underpinned by a systematic computational study, which allowed us to quantify the energies associated with LD interactions and to analyze intermolecular close contacts and attractions in detail.
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Affiliation(s)
- Daniel Ebeling
- Institute of Applied Physics, Justus-Liebig University , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Marina Šekutor
- Institute of Organic Chemistry, Justus-Liebig University , Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Marvin Stiefermann
- Institute of Applied Physics, Justus-Liebig University , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Jalmar Tschakert
- Institute of Applied Physics, Justus-Liebig University , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Jeremy E P Dahl
- Stanford Institute for Materials and Energy Sciences , Stanford, California 94305, United States
| | - Robert M K Carlson
- Stanford Institute for Materials and Energy Sciences , Stanford, California 94305, United States
| | - André Schirmeisen
- Institute of Applied Physics, Justus-Liebig University , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus-Liebig University , Heinrich-Buff-Ring 17, 35392 Giessen, Germany
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19
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Zint S, Ebeling D, Schlöder T, Ahles S, Mollenhauer D, Wegner HA, Schirmeisen A. Imaging Successive Intermediate States of the On-Surface Ullmann Reaction on Cu(111): Role of the Metal Coordination. ACS Nano 2017; 11:4183-4190. [PMID: 28346826 DOI: 10.1021/acsnano.7b01109] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The in-depth knowledge about on-surface reaction mechanisms is crucial for the tailor-made design of covalently bonded organic frameworks, for applications such as nanoelectronic or -optical devices. Latest developments in atomic force microscopy, which rely on functionalizing the tip with single CO molecules at low temperatures, allow to image molecular systems with submolecular resolution. Here, we are using this technique to study the complete reaction pathway of the on-surface Ullmann-type coupling between bromotriphenylene molecules on a Cu(111) surface. All steps of the Ullmann reaction, i.e., bromotriphenylenes, triphenylene radicals, organometallic intermediates, and bistriphenylenes, were imaged with submolecular resolution. Together with density functional theory calculations with dispersion correction, our study allows to address the long-standing question of how the organometallic intermediates are coordinated via Cu surface or adatoms.
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Affiliation(s)
- Sören Zint
- Institute of Applied Physics (IAP), Justus Liebig University Giessen , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Daniel Ebeling
- Institute of Applied Physics (IAP), Justus Liebig University Giessen , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | | | | | | | | | - André Schirmeisen
- Institute of Applied Physics (IAP), Justus Liebig University Giessen , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
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20
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Zhao C, Ebeling D, Siretanu I, van den Ende D, Mugele F. Extracting local surface charges and charge regulation behavior from atomic force microscopy measurements at heterogeneous solid-electrolyte interfaces. Nanoscale 2015; 7:16298-311. [PMID: 26377347 DOI: 10.1039/c5nr05261k] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We present a method to determine the local surface charge of solid-liquid interfaces from Atomic Force Microscopy (AFM) measurements that takes into account shifts of the adsorption/desorption equilibria of protons and ions as the cantilever tip approaches the sample. We recorded AFM force distance curves in dynamic mode with sharp tips on heterogeneous silica surfaces partially covered by gibbsite nano-particles immersed in an aqueous electrolyte with variable concentrations of dissolved NaCl and KCl at pH 5.8. Forces are analyzed in the framework of Derjaguin-Landau-Verwey-Overbeek (DLVO) theory in combination with a charge regulation boundary that describes adsorption and desorption reactions of protons and ions. A systematic method to extract the equilibrium constants of these reactions by simultaneous least-squared fitting to experimental data for various salt concentrations is developed and is shown to yield highly consistent results for silica-electrolyte interfaces. For gibbsite-electrolyte interfaces, the surface charge can be determined, yet, an unambiguous identification of the relevant surface speciation reactions is not possible, presumably due to a combination of intrinsic chemical complexity and heterogeneity of the nano-particle surfaces.
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Affiliation(s)
- Cunlu Zhao
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
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21
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Hentschel C, Jiang L, Ebeling D, Zhang JC, Chen XD, Chi LF. Conductance measurements of individual polypyrrole nanobelts. Nanoscale 2015; 7:2301-2305. [PMID: 25594494 DOI: 10.1039/c4nr06785a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present here a study on the electrical conduction properties of individual polypyrrole nanobelts by using conductive atomic force microscopy and discuss a general effect while probing soft materials. A length-dependent analysis demonstrates that the tip could induce local defects into the polymer structure and, thus diminishes the electrical conduction.
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Affiliation(s)
- C Hentschel
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM) & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren-Ai Road, Suzhou Jiangsu 215123, P. R. China.
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22
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Abstract
We present experimental and computational investigations of tetramodal and pentamodal atomic force microscopy (AFM), respectively, whereby the first four or five flexural eigenmodes of the cantilever are simultaneously excited externally. This leads to six to eight additional observables in the form of amplitude and phase signals, with respect to the monomodal amplitude modulation method. We convert these additional observables into three or four dissipation and virial expressions, and show that these quantities can provide enhanced contrast that would otherwise remain hidden in the original observables. We also show that the complexity of the multimodal impact leads to significant energy transfer between the active eigenmodes, such that the dissipated power for individual eigenmodes may be positive or negative, while the total dissipated power remains positive. These results suggest that the contrast of individual eigenmodes in multifrequency AFM should be not be considered in isolation and that it may be possible to use different eigenfrequencies to probe sample properties that respond to different relaxation times.
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Affiliation(s)
- Sangmin An
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA. Maryland NanoCenter, University of Maryland, College Park, MD 20742, USA
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23
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Stubinitzky C, Bijeljanin A, Antusch L, Ebeling D, Hölscher H, Wagenknecht HA. Bifunctional DNA architectonics: three-way junctions with sticky perylene bisimide caps and a central metal lock. Chemistry 2014; 20:12009-14. [PMID: 25098549 DOI: 10.1002/chem.201402956] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Indexed: 12/23/2022]
Abstract
A new type of a bifunctional DNA architecture based on a three way junction is developed that combines the structural motif of sticky perylene bisimide caps with a tris-bipyridyl metal ion lock in the center part. A clear stabilizing effect was observed in the presence of Fe(3+), Ni(2+) and Zn(2+) by the formation of corresponding bipyridyl complexes in the branching part of the DNA three way junctions. The dimerization of the 5'-terminally attached perylene diimides (PDI) chromophores by hydrophobic interactions can be followed by significant changes in the UV/Vis absorption and steady-state fluorescence. The PDI-mediated DNA assembly occurs at temperatures below the melting temperature and is not influenced by the metal-ion bipyridyl locks in the central part. The corresponding AFM images revealed the formation of higher-ordered structures as the result of DNA assemblies mediated by the PDI interactions.
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Affiliation(s)
- Claudia Stubinitzky
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany), Fax: (+49)-721-608-44825
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24
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Eslami B, Ebeling D, Solares SD. Trade-offs in sensitivity and sampling depth in bimodal atomic force microscopy and comparison to the trimodal case. Beilstein J Nanotechnol 2014; 5:1144-51. [PMID: 25161847 PMCID: PMC4142983 DOI: 10.3762/bjnano.5.125] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 06/27/2014] [Indexed: 05/26/2023]
Abstract
This paper presents experiments on Nafion(®) proton exchange membranes and numerical simulations illustrating the trade-offs between the optimization of compositional contrast and the modulation of tip indentation depth in bimodal atomic force microscopy (AFM). We focus on the original bimodal AFM method, which uses amplitude modulation to acquire the topography through the first cantilever eigenmode, and drives a higher eigenmode in open-loop to perform compositional mapping. This method is attractive due to its relative simplicity, robustness and commercial availability. We show that this technique offers the capability to modulate tip indentation depth, in addition to providing sample topography and material property contrast, although there are important competing effects between the optimization of sensitivity and the control of indentation depth, both of which strongly influence the contrast quality. Furthermore, we demonstrate that the two eigenmodes can be highly coupled in practice, especially when highly repulsive imaging conditions are used. Finally, we also offer a comparison with a previously reported trimodal AFM method, where the above competing effects are minimized.
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Affiliation(s)
- Babak Eslami
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
| | - Daniel Ebeling
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
- present address: Institute of Applied Physics, Justus Liebig University of Giessen, 35392 Giessen, Germany
| | - Santiago D Solares
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
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25
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Siretanu I, Ebeling D, Andersson MP, Stipp SLS, Philipse A, Stuart MC, van den Ende D, Mugele F. Direct observation of ionic structure at solid-liquid interfaces: a deep look into the Stern Layer. Sci Rep 2014; 4:4956. [PMID: 24850566 PMCID: PMC4030399 DOI: 10.1038/srep04956] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 04/22/2014] [Indexed: 12/03/2022] Open
Abstract
The distribution of ions and charge at solid-water interfaces plays an essential role in a wide range of processes in biology, geology and technology. While theoretical models of the solid-electrolyte interface date back to the early 20th century, a detailed picture of the structure of the electric double layer has remained elusive, largely because of experimental techniques have not allowed direct observation of the behaviour of ions, i.e. with subnanometer resolution. We have made use of recent advances in high-resolution Atomic Force Microscopy to reveal, with atomic level precision, the ordered adsorption of the mono- and divalent ions that are common in natural environments to heterogeneous gibbsite/silica surfaces in contact with aqueous electrolytes. Complemented by density functional theory, our experiments produce a detailed picture of the formation of surface phases by templated adsorption of cations, anions and water, stabilized by hydrogen bonding.
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Affiliation(s)
- Igor Siretanu
- 1] Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands [2]
| | - Daniel Ebeling
- 1] Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands [2]
| | - Martin P Andersson
- Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - S L Svane Stipp
- Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Albert Philipse
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Martien Cohen Stuart
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Dirk van den Ende
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Frieder Mugele
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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26
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Ebeling D, Eslami B, Solares SDJ. Visualizing the subsurface of soft matter: simultaneous topographical imaging, depth modulation, and compositional mapping with triple frequency atomic force microscopy. ACS Nano 2013; 7:10387-96. [PMID: 24131492 DOI: 10.1021/nn404845q] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Characterization of subsurface morphology and mechanical properties with nanoscale resolution and depth control is of significant interest in soft matter fields like biology, polymer science, and even in future applications like nanomanufacturing, where buried structural and compositional features are important to the functionality of the system. However, controllably "feeling" the subsurface is a challenging task for which the available imaging tools are relatively limited. In this paper, we propose a trimodal atomic force microscopy (AFM) imaging scheme, whereby three eigenmodes of the microcantilever probe are used as separate control "knobs" to simultaneously measure the topography, modulate sample indentation by the tip during tip-sample impact, and map compositional contrast, respectively. We illustrate this multifrequency imaging approach through computational simulation and experiments conducted on ultrathin polymer films with embedded glass nanoparticles in ambient air. By actively increasing the tip-sample indentation using a higher eigenmode of the cantilever, we are able to gradually and controllably reveal glass nanoparticles which are buried tens of nanometers deep under the surface, while still being able to refocus on the surface.
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Affiliation(s)
- Daniel Ebeling
- Department of Mechanical Engineering, University of Maryland , College Park, Maryland 20742, United States
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27
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Ebeling D, Solares SD. Amplitude modulation dynamic force microscopy imaging in liquids with atomic resolution: comparison of phase contrasts in single and dual mode operation. Nanotechnology 2013; 24:135702. [PMID: 23478354 DOI: 10.1088/0957-4484/24/13/135702] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We present a systematic analysis of the atomic-scale imaging capabilities for mineral surfaces in a liquid environment in single and dual mode amplitude modulation dynamic force microscopy. To study the difference in sensitivity between the first and second eigenmode phase signals we investigate the observed atomic-scale contrasts of the mica-water interface under varying imaging conditions. For this purpose, we systematically change the main imaging parameters including the setpoint amplitude of the imaging feedback, the free oscillation amplitudes of the first and second flexural eigenmodes, and their ratio. This allows for an in-depth analysis of the sensitivities of the first and second eigenmode phase signals to draw conclusions regarding the underlying physical mechanisms and the interpretation of the contrast in the multi-frequency technique.
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Affiliation(s)
- Daniel Ebeling
- Department of Mechanical Engineering, University of Maryland, 2181 Glenn L Martin Hall, College Park, MD 20742, USA.
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28
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Ebeling D, Solares SD. Bimodal atomic force microscopy driving the higher eigenmode in frequency-modulation mode: Implementation, advantages, disadvantages and comparison to the open-loop case. Beilstein J Nanotechnol 2013; 4:198-207. [PMID: 23616939 PMCID: PMC3628543 DOI: 10.3762/bjnano.4.20] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 03/04/2013] [Indexed: 05/24/2023]
Abstract
We present an overview of the bimodal amplitude-frequency-modulation (AM-FM) imaging mode of atomic force microscopy (AFM), whereby the fundamental eigenmode is driven by using the amplitude-modulation technique (AM-AFM) while a higher eigenmode is driven by using either the constant-excitation or the constant-amplitude variant of the frequency-modulation (FM-AFM) technique. We also offer a comparison to the original bimodal AFM method, in which the higher eigenmode is driven with constant frequency and constant excitation amplitude. General as well as particular characteristics of the different driving schemes are highlighted from theoretical and experimental points of view, revealing the advantages and disadvantages of each. This study provides information and guidelines that can be useful in selecting the most appropriate operation mode to characterize different samples in the most efficient and reliable way.
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Affiliation(s)
- Daniel Ebeling
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
| | - Santiago D Solares
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
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29
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Ebeling A, Hartmann V, Rockman A, Armstrong A, Balza R, Erbe J, Ebeling D. Silver Nanoparticle Adsorption to Soil and Water Treatment Residuals and Impact on Zebrafish in a Lab-scale Constructed Wetland. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/cweee.2013.23b004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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30
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Sengupta S, Ebeling D, Patwardhan S, Zhang X, von Berlepsch H, Böttcher C, Stepanenko V, Uemura S, Hentschel C, Fuchs H, Grozema FC, Siebbeles LDA, Holzwarth AR, Chi L, Würthner F. Biosupramolecular Nanowires from Chlorophyll Dyes with Exceptional Charge-Transport Properties. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201201961] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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31
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Sengupta S, Ebeling D, Patwardhan S, Zhang X, von Berlepsch H, Böttcher C, Stepanenko V, Uemura S, Hentschel C, Fuchs H, Grozema FC, Siebbeles LDA, Holzwarth AR, Chi L, Würthner F. Biosupramolecular nanowires from chlorophyll dyes with exceptional charge-transport properties. Angew Chem Int Ed Engl 2012; 51:6378-82. [PMID: 22644905 DOI: 10.1002/anie.201201961] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Indexed: 11/10/2022]
Abstract
Conductive tubes: Self-assembled nanotubes of a bacteriochlorophyll derivative are reminiscent of natural chlorosomal light-harvesting assemblies. After deposition on a substrate that consists of a non-conductive silicon oxide surface (see picture, brown) and contacting the chlorin nanowires to a conductive polymer (yellow), they show exceptional charge-transport properties.
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Affiliation(s)
- Sanchita Sengupta
- Universität Würzburg, Institut für Organische Chemie and Center for Nanosystems Chemistry, Am Hubland, 97074 Würzburg, Germany
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32
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Ebeling D, van den Ende D, Mugele F. Electrostatic interaction forces in aqueous salt solutions of variable concentration and valency. Nanotechnology 2011; 22:305706. [PMID: 21719972 DOI: 10.1088/0957-4484/22/30/305706] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We use atomic force microscopy (AFM) to determine electrostatic interactions between Si tips and Si wafers in aqueous electrolytes of variable composition. We demonstrate that dynamic force spectroscopy (DFS) in the frequency modulation (FM) mode with stiff cantilevers and sharp tips allows for a continuous detection of the tip-sample interactions without mechanical jump-to-contact instability and with substantially higher lateral resolution than standard colloidal probe measurements. For four different species of salt (NaCl, KCl, MgCl(2), CaCl(2)) we find repulsive electrostatic forces at the lowest salt concentrations (1 mM) that become progressively screened until they are dominated by attractive van der Waals forces at the highest concentration (100 mM). For the divalent cations the crossover from repulsive to attractive forces occurs at lower concentrations than for monovalent cations. Surface charges extracted from fits to standard Poisson-Boltzmann double layer theory indicate a rather weak dependence of the surface charge on the ion concentration. The high lateral resolution of our approach is illustrated by a 2D force field measurement over a patterned surface of a supported lipid bilayer on a mica substrate.
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Affiliation(s)
- Daniel Ebeling
- Physics of Complex Fluids and MESA + Institute for Nanotechnology, Department of Science and Technology, University of Twente, Enschede, The Netherlands.
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33
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Wang T, Ebeling D, Yang J, Du C, Chi L, Fuchs H, Yan D. Weak Epitaxy Growth of Copper Hexadecafluorophthalocyanine (F16CuPc) on p-Sexiphenyl Monolayer Film. J Phys Chem B 2009; 113:2333-7. [DOI: 10.1021/jp8080639] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tong Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, and Graduate School of Chinese Academy of Sciences, Changchun 130022, People’s Republic of China, and Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, and Center for Nanotechnology (CeNTech), Heisenbergstr. 11, 48149 Münster, Germany
| | - Daniel Ebeling
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, and Graduate School of Chinese Academy of Sciences, Changchun 130022, People’s Republic of China, and Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, and Center for Nanotechnology (CeNTech), Heisenbergstr. 11, 48149 Münster, Germany
| | - Junliang Yang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, and Graduate School of Chinese Academy of Sciences, Changchun 130022, People’s Republic of China, and Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, and Center for Nanotechnology (CeNTech), Heisenbergstr. 11, 48149 Münster, Germany
| | - Chuan Du
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, and Graduate School of Chinese Academy of Sciences, Changchun 130022, People’s Republic of China, and Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, and Center for Nanotechnology (CeNTech), Heisenbergstr. 11, 48149 Münster, Germany
| | - Lifeng Chi
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, and Graduate School of Chinese Academy of Sciences, Changchun 130022, People’s Republic of China, and Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, and Center for Nanotechnology (CeNTech), Heisenbergstr. 11, 48149 Münster, Germany
| | - Harald Fuchs
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, and Graduate School of Chinese Academy of Sciences, Changchun 130022, People’s Republic of China, and Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, and Center for Nanotechnology (CeNTech), Heisenbergstr. 11, 48149 Münster, Germany
| | - Donghang Yan
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, and Graduate School of Chinese Academy of Sciences, Changchun 130022, People’s Republic of China, and Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, and Center for Nanotechnology (CeNTech), Heisenbergstr. 11, 48149 Münster, Germany
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34
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Abstract
Experiments performed by friction force microscopy at atomic-scale surface steps on graphite, MoS2, and NaCl in ambient conditions are presented. Both step-down and step-up scans exhibit higher frictional forces at the edge, but distinguish in their load dependence: While the additional frictional force due to the step edge increases linearly with load if the tip has to jump a step up, it remains constant for downward jumps. This phenomenon represents a universal effect that can be explained in terms of a modified Prandtl-Tomlinson model featuring a Schwoebel-Ehrlich barrier at steps.
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Affiliation(s)
- Hendrik Hölscher
- Institute for Microstructure Technology, Forschungszentrum Karlsruhe, P.O. Box 3670, 76021 Karlsruhe, Germany.
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35
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Müller NG, Ebeling D. Attention-modulated activity in visual cortex—More than a simple ‘spotlight’. Neuroimage 2008; 40:818-827. [DOI: 10.1016/j.neuroimage.2007.11.060] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 11/24/2007] [Accepted: 11/28/2007] [Indexed: 11/16/2022] Open
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36
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Domínguez-Gutiérrez D, De Paoli G, Guerrero-Martínez A, Ginocchietti G, Ebeling D, Eiser E, De Cola L, Elsevier CJ. Inverted aggregates of luminescent ruthenium metallosurfactants. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b717859j] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Schmutz JE, Hölscher H, Ebeling D, Schäfer MM, Anczykowski B. Mapping the tip–sample interactions on DPPC and DNA by dynamic force spectroscopy under ambient conditions. Ultramicroscopy 2007; 107:875-81. [PMID: 17566660 DOI: 10.1016/j.ultramic.2007.04.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Self-assembled monolayers of DPPC and DNA adsorbed on mica are examined by dynamic force spectroscopy under ambient conditions. By a systematic recording of the frequency shift caused by the tip-sample interaction we determine the corresponding tip-sample potential and force curves. In difference to the conventional measurement of force-vs.-distance curves this technique allows the continuous measurement of tip-sample forces without instabilities caused by a jump-to-contact. Due to the systematic mapping of the tip-sample interaction we are able to compute contour maps of the tip-surface potential of the DPPC films and to extract local properties like contact stiffness and adhesion force. The lateral resolution capabilities of the introduced spectroscopy method are examined by the example of lambda phage DNA.
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Affiliation(s)
- J-E Schmutz
- Center for Nanotechnology (CeNTech), Heisenbergstr. 11, 48149 Münster, Germany
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38
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Ebeling D, Hölscher H, Fuchs H, Anczykowski B, Schwarz UD. Imaging of biomaterials in liquids: a comparison between conventional and Q-controlled amplitude modulation ('tapping mode') atomic force microscopy. Nanotechnology 2006; 17:S221-S226. [PMID: 21727418 DOI: 10.1088/0957-4484/17/7/s20] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Lambda phage DNA and DPPC thin films are imaged in liquids by atomic force microscopy applying the amplitude modulation mode ('tapping mode') with active enhancement of the Q-factor by a 'Q-control' electronics. The topography of the resulting images is compared with images obtained without active Q-control. To enable a meaningful comparison, individual scan lines are alternately recorded with and without Q-factor enhancement using scan parameters optimized for each mode separately. As the major finding, significant height differences of topographical features are observed between the two modes. The heights measured with active Q-control are reproducibly higher compared to the ones observed without Q enhancement. This effect is attributed to the reduction of tip-sample forces by Q-control.
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Affiliation(s)
- D Ebeling
- Center for Nanotechnology (CeNTech), Gievenbecker Weg 11, 48149 Münster, Germany. Physikalisches Institut, Westfälische Wilhelms Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
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Ebeling D, Müller NG. Activity in Retinotopic Visual Cortex under Focused Spatial Attention Distinguishes Empty from Distracter Locations. KLIN NEUROPHYSIOL 2004. [DOI: 10.1055/s-2004-831958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Barditch-Crovo P, Toole J, Hendrix CW, Cundy KC, Ebeling D, Jaffe HS, Lietman PS. Anti-human immunodeficiency virus (HIV) activity, safety, and pharmacokinetics of adefovir dipivoxil (9-[2-(bis-pivaloyloxymethyl)-phosphonylmethoxyethyl]adenine) in HIV-infected patients. J Infect Dis 1997; 176:406-13. [PMID: 9237705 DOI: 10.1086/514057] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A randomized, double-blind, placebo-controlled, dose-escalation study of adefovir dipivoxil, an oral prodrug of adefovir, was conducted in 36 human immunodeficiency virus (HIV)-infected subjects to evaluate its anti-HIV activity, safety, and pharmacokinetics. Subjects received placebo or one of three dosages of adefovir dipivoxil daily for 14 days. Median decreases in serum p24 antigen of 31% (P = .02), 25% (P = .31), and 30% (P = .01) occurred in each drug-treated group, respectively, compared with an increase of 17% in the placebo group. Median decreases in serum HIV RNA of 0.4-0.6 log10 copies/mL occurred in the drug-treated groups (P = .03), compared with no change in the placebo group. Gastrointestinal complaints and reversible liver transaminase elevations were the most frequently noted adverse events. Decreases in serum free carnitine occurred in each drug-treated group during treatment. After 14 days of dosing, adefovir dipivoxil demonstrated anti-HIV activity and was best tolerated at the lowest dosage studied, 125 mg daily.
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Affiliation(s)
- P Barditch-Crovo
- Johns Hopkins University School of Medicine, Division of Clinical Pharmacology, Baltimore, Maryland, USA
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Schmidt H, Ebeling D, Bauer H, Bŏhrer H, Gebhard MM, Martin E. Influence of the platelet-activating factor receptor antagonist BN52021 on endotoxin-induced leukocyte adherence in rat mesenteric venules. J Surg Res 1996; 60:29-35. [PMID: 8592427 DOI: 10.1006/jsre.1996.0006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The aim of this study was to investigate the influence of the platelet-activating factor (PAF) antagonist BN52021 on endotoxin-induced leukocyte-endothelium interactions and on venular microcirculation. The rates of leukocyte adherence and changes in red cell velocity, volumetric blood flow, vessel diameter, and venular shear rate were monitored in rat mesenteric venules following intravenous lipopolysaccharide (LPS) exposure (15 mg/kg body wt). The experiments were performed in LPS-treated control animals and in animals pretreated with the PAF receptor antagonist BN52021. LPS exposure induced a marked increase in adherent leukocytes in the control group compared to the BN52021-pretreated group. Thirty minutes after LPS injection, 6.1 +/- 0.8 leukocytes were adherent to 100 microns of venule in the control group compared to 2.5 +/- 0.5 in BN52021-pretreated animals (P < 0.01). The increased leukocyte adherence in the control group was accompanied by leukocytopenia. Red cell velocity, volumetric blood flow, vessel diameter, and venular shear rate did not differ between groups, indicating that increased leukocyte adherence in the control group was not due to diminished hydrodynamic dispersal forces. The attenuation of leukocyte adherence by the PAF receptor antagonist BN52021 suggests that PAF is involved in the mediation of the initial process of leukocyte sticking to the endothelium after LPS stimulation.
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Affiliation(s)
- H Schmidt
- Department of Anesthesiology, University of Heidelberg, Germany
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Schmidt H, Ebeling D, Bauer H, Bach A, Bohrer H, Gebhard MM, Martin E. Ketamine attenuates endotoxin-induced leukocyte adherence in rat mesenteric venules. Crit Care Med 1995; 23:2008-14. [PMID: 7497723 DOI: 10.1097/00003246-199512000-00009] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVES To determine the influence of ketamine on endotoxin-induced leukocyte adherence and venular microhemodynamics. DESIGN Randomized, controlled trial. SETTING Experimental laboratory. SUBJECTS Thirty male Wistar rats. INTERVENTIONS The rats were pretreated with ketamine (10 mg/kg iv) or 0.9% saline, and both groups were given endotoxin (Escherichia coli lipopolysaccharide; 5 mg/kg iv). The control group received two doses of 0.9% saline. MEASUREMENTS AND MAIN RESULTS The rates of leukocyte adherence and changes in microhemodynamics were monitored in rat mesenteric venules, using in vivo video microscopy. The number of adherent leukocytes was determined on-line in 10-min intervals from 60 mins before until 2 hrs after endotoxin administration. Venular diameters, red blood cell velocity, volumetric blood flow, and the venular wall shear rate were monitored before and at 10, 30, and 60 mins after endotoxin exposure. A 6.3-fold increase in the number of adherent leukocytes was observed 10 mins after administration of endotoxin when compared with control animals (5.87 +/- 0.69 vs. 0.93 +/- 0.21 adherent cells/100 microns; p < .001). This increase remained unchanged for 120 mins. In ketamine-pretreated rats, a 2.6-fold increase in leukocyte adherence occurred during the first 20 mins after endotoxin exposure (2.40 +/- 0.46 vs. 0.93 +/- 0.21 adherent cells/100 microns; p < .01). However, no difference in the number of adherent leukocytes between ketamine-pretreated and control animals was found after this 20-min period. In animals of the control group, no increase in leukocyte adherence occurred during the entire observation time. Diameters of mesenteric venules did not change after endotoxin exposure in any of the groups. Red blood cell velocity and venular blood flow in the endotoxin-treated groups decreased 10 mins after the injection of endotoxin when compared with controls, but these values did not show any difference when they were compared between ketamine and saline-pretreated animals. Similarly, venular wall shear rate in the endotoxin-treated groups decreased 10 and 30 mins after injection of endotoxin. However, no significant difference occurred between ketamine and saline-pretreated animals. CONCLUSIONS Pretreatment with ketamine attenuates endotoxin-induced leukocyte adherence by a shear rate-independent mechanism, suggesting reduced expression of adhesion molecules. These results indicate that ketamine exerts an anti-inflammatory effect, which might be beneficial in septic patients.
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Affiliation(s)
- H Schmidt
- Department of Anesthesiology, University of Heidelberg, Germany
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Cundy KC, Barditch-Crovo P, Walker RE, Collier AC, Ebeling D, Toole J, Jaffe HS. Clinical pharmacokinetics of adefovir in human immunodeficiency virus type 1-infected patients. Antimicrob Agents Chemother 1995; 39:2401-5. [PMID: 8585716 PMCID: PMC162955 DOI: 10.1128/aac.39.11.2401] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The pharmacokinetics and bioavailability of adefovir [9-[2-(phosphonomethoxy)ethyl]adenine] were examined at two dose levels in three phase I/II studies in 28 human immunodeficiency type 1-infected patients. The concentrations of adefovir in serum following the intravenous infusion of 1.0 or 3.0 mg/kg of body weight were dose proportional and declined biexponentially, with an overall mean +/- standard deviation terminal half-life of 1.6 +/- 0.5 h (n = 28). Approximately 90% of the intravenous dose was recovered unchanged in the urine in 12 h, and more than 98% was recovered by 24 h postdosing. The overall mean +/- standard deviation total serum clearance of the drug (223 +/- 53 ml/h/kg; n = 25) approximated the renal clearance (205 +/- 78 ml/h/kg; n = 20), which was significantly higher (P < 0.01) than the baseline creatinine clearance in the same patients (88 +/- 18 ml/h/kg; n = 25). Since adefovir is essentially completely unbound in plasma or serum, these data indicate that active tubular secretion accounted for approximately 60% of the clearance of adefovir. The steady-state volume of distribution of adefovir (418 +/- 76 ml/kg; n = 28) suggests that the drug was distributed in total body water. Repeated daily dosing with adefovir at 1.0 mg/kg/day (n = 8) and 3.0 mg/kg/day (n = 4) for 22 days did not significantly alter the pharmacokinetics of the drug; there was no evidence of accumulation. The oral bioavailability of adefovir at a 3.0-mg/kg dose was < 12% (n = 5) on the basis of the concentrations in serum or 16.4% +/- 16.0% on the basis of urinary recovery. The subcutaneous bioavailability of adefovir at a 3.0-mg/kg dose was 102% +/- 8.3% (n = 5) on the basis of concentrations in serum or 84.8% +/- 28.5% on the basis of urinary recovery. These data are consistent with preclinical observations in various species.
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Affiliation(s)
- K C Cundy
- Gilead Sciences, Inc., Foster City, California 94404, USA
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Anderson LM, Giner-Sorolla A, Ebeling D. Effects of imipramine, nitrite, and dimethylnitrosamine on reproduction in mice. Res Commun Chem Pathol Pharmacol 1978; 19:311-27. [PMID: 644123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Administration of the tricyclic dibenzazepine drug imipramine, a tertiary amine, in the food (100 mg/kg) or sodium nitrite (1 g/liter) or dimethylnitrosamine (0.1 ppm) in the drinking water of Swiss CD-1 mice before and during pregnancy, resulted in increased perinatal death of the offspring compared to controls. Administration of imipramine and nitrite together had no effect on perinatal survival, but instead resulted in infertility or delayed impregnation in some females. A biological synergism or in vivo chemical interaction of the two chemicals is suggested.
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Del Pozo E, Darragh A, Lancranjan I, Ebeling D, Burmeister P, Bühler F, Marbach P, Braun P. Effect of bromocriptin on the endocrine system and fetal development. Clin Endocrinol (Oxf) 1977; 6 Suppl:47S-55S. [PMID: 617071 DOI: 10.1111/j.1365-2265.1977.tb03338.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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