1
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Liu Z, Wang Z, Guckel J, Akbarian Z, Seifert TJ, Park D, Schlickum U, Stosch R, Etzkorn M. Controlling Nanoparticle Distance by On-Surface DNA-Origami Folding. Small 2024:e2310955. [PMID: 38634220 DOI: 10.1002/smll.202310955] [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] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 03/11/2024] [Indexed: 04/19/2024]
Abstract
DNA origami is a flexible platform for the precise organization of nano-objects, enabling numerous applications from biomedicine to nano-photonics. Its huge potential stems from its high flexibility that allows customized structures to meet specific requirements. The ability to generate diverse final structures from a common base by folding significantly enhances design variety and is regularly occurring in liquid. This study describes a novel approach that combines top-down lithography with bottom-up DNA origami techniques to control folding of the DNA origami with the adsorption on pre-patterned surfaces. Using this approach, tunable plasmonic dimer nano-arrays are fabricated on a silicon surface. This involves employing electron beam lithography to create adsorption sites on the surface and utilizing self-organized adsorption of DNA origami functionalized with two gold nanoparticles (AuNPs). The desired folding of the DNA origami helices can be controlled by the size and shape of the adsorption sites. This approach can for example be used to tune the center-to-center distance of the AuNPs dimers on the origami template. To demonstrate this technique's efficiency, the Raman signal of dye molecules (carboxy tetramethylrhodamine, TAMRA) coated on the AuNPs surface are investigated. These findings highlight the potential of tunable DNA origami-based plasmonic nanostructures for many applications.
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Affiliation(s)
- Zhe Liu
- Institute of Applied Physics, Technische Universität Braunschweig, 38106, Braunschweig, Germany
| | - Zunhao Wang
- Physikalisch-Technische Bundesanstalt, 38106, Braunschweig, Germany
| | - Jannik Guckel
- Physikalisch-Technische Bundesanstalt, 38106, Braunschweig, Germany
| | - Ziba Akbarian
- Institute of Applied Physics, Technische Universität Braunschweig, 38106, Braunschweig, Germany
| | - Tim J Seifert
- Institute of Applied Physics, Technische Universität Braunschweig, 38106, Braunschweig, Germany
| | - Daesung Park
- Physikalisch-Technische Bundesanstalt, 38106, Braunschweig, Germany
| | - Uta Schlickum
- Institute of Applied Physics, Technische Universität Braunschweig, 38106, Braunschweig, Germany
| | - Rainer Stosch
- Physikalisch-Technische Bundesanstalt, 38106, Braunschweig, Germany
| | - Markus Etzkorn
- Institute of Applied Physics, Technische Universität Braunschweig, 38106, Braunschweig, Germany
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2
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Liu Z, Wang Z, Guckel J, Park D, Lalkens B, Stosch R, Etzkorn M. Positional Control of DNA Origami based Gold Dimer Hybrid Nanostructures on Pre-Structured Surfaces. Nanotechnology 2023. [PMID: 37442100 DOI: 10.1088/1361-6528/ace726] [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] [Indexed: 07/15/2023]
Abstract
This study explores important parameters for achieving a high-level positional control of DNA-nanoparticle hybrid structures by drop-casting onto a pre-structured silicon surface, in which the active adsorption sites were defined using electron beam lithography (EBL). By confining the adsorption sites to the scale of the DNA origami, we create multi-dimensional patterns and study the effect of diffusion and hybrid nanostructure concentration in the liquid on site occupation. We also propose a physical diffusion model that highlights the importance of surface diffusion in facilitating the adsorption of hybrid nanostructure onto active sites, particularly for two and one-dimensional adsorption sites. Our study shows prominent results of the hybrid nanostructure's selective adsorption, indicating high adsorption efficiency and precise control over the position, as well as the spatial orientation. We anticipate similar results in related systems, both in terms of different surfaces and similar DNA structures. Overall, our findings offer promising prospects for the development of large-scale nanoarrays on micrometer-scale surfaces with nanometer precision and orientation control.
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Affiliation(s)
- Zhe Liu
- Institute of Applied Physics, TU Braunschweig University, Mendelssohnstr. 2, Braunschweig, Lower Saxony, 38106, GERMANY
| | - Zunhao Wang
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, Braunschweig, Niedersachsen, 38116, GERMANY
| | - Jannik Guckel
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, Braunschweig, Niedersachsen, 38116, GERMANY
| | - Daesung Park
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, Braunschweig, Niedersachsen, 38116, GERMANY
| | - Birka Lalkens
- Institute of Semiconductor Technology, TU Braunschweig University, Hans Sommer Strasse 66, Braunschweig, Lower Saxony, 38106, GERMANY
| | - Rainer Stosch
- General and Inorganic Chemistry, Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig, Braunschweig, 38116, GERMANY
| | - Markus Etzkorn
- Institute of Applied Physics, TU Braunschweig University, Mendelssohnstr. 2, Braunschweig, Lower Saxony, 38106, GERMANY
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3
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Alula MT, Madingwane ML, Yan H, Lemmens P, Zhe L, Etzkorn M. Biosynthesis of bifunctional silver nanoparticles for catalytic reduction of organic pollutants and optical monitoring of mercury (II) ions using their oxidase-mimic activity. Environ Sci Pollut Res Int 2022; 29:81938-81953. [PMID: 35739451 DOI: 10.1007/s11356-022-21619-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 06/18/2022] [Indexed: 06/15/2023]
Abstract
In this study, an aqueous extract of Sclerocarya birrea leaves was used as a reducing agent to synthesize silver nanoparticles (AgNPs). The synthesis was carried out at room temperature and was both rapid and simple. Different characterization techniques such as UV/visible spectroscopy, surface-enhanced Raman spectroscopy, X-ray diffraction, and focused ion beam scanning electron microscopy were used to confirm the formation of AgNPs. The synthesized nanoparticles exhibited catalytic activity for the reduction of 4-nitrophenol, methyl orange, methylene blue, and rhodamine 6G. The catalytic activity was monitored by measuring the UV/visible absorbance spectra of the compounds using sodium borohydride as a reducing agent and found to be high. Additionally, the particles displayed oxidase-like activity. In the presence of AgNPs, 3, 3', 5, 5'-tetramethylbenzidine (TMB) which is colorless was transformed to oxidized TMB, which is blue, using dissolved oxygen as the oxidant. In the presence of Hg2+, the oxidase-like activity was enhanced. On the basis of this observation, an assay for the analysis of Hg2+ was developed. The linear range of the calibration curve is wide (0-600 µM) and the limit of detection (LOD) is low, as small as 34.8 nM. The method is strongly selective towards Hg2+. Tap water obtained from the laboratory where these experiments were carried out was used to study the feasibility of the method in real sample analyses.
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Affiliation(s)
- Melisew Tadele Alula
- Department of Chemical and Forensic Sciences, Faculty of Science, Botswana International University of Science and Technology, Plot 10071, Private Bag 16, Palapye, Botswana.
| | - Mildred Lesang Madingwane
- Department of Chemical and Forensic Sciences, Faculty of Science, Botswana International University of Science and Technology, Plot 10071, Private Bag 16, Palapye, Botswana
| | - Hongdan Yan
- Institute for Condensed Matter Physics and Lab. for Emergent Nanometrology (LENA), Braunschweig University of Technology, Mendelssohnsstr. 3, 38106, Braunschweig, Germany
| | - Peter Lemmens
- Institute for Condensed Matter Physics and Lab. for Emergent Nanometrology (LENA), Braunschweig University of Technology, Mendelssohnsstr. 3, 38106, Braunschweig, Germany
| | - Liu Zhe
- Institute Applied Physics and Lab. for Emergent Nanometrology (LENA), Braunschweig University of Technology, Mendelssohnsstr. 3, 38106, Braunschweig, Germany
| | - Markus Etzkorn
- Institute Applied Physics and Lab. for Emergent Nanometrology (LENA), Braunschweig University of Technology, Mendelssohnsstr. 3, 38106, Braunschweig, Germany
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4
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Rösch EL, Zhong J, Lak A, Liu Z, Etzkorn M, Schilling M, Ludwig F, Viereck T, Lalkens B. Point-of-need detection of pathogen-specific nucleic acid targets using magnetic particle spectroscopy. Biosens Bioelectron 2021; 192:113536. [PMID: 34358999 PMCID: PMC8314793 DOI: 10.1016/j.bios.2021.113536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/23/2021] [Accepted: 07/24/2021] [Indexed: 12/23/2022]
Abstract
The ongoing COVID-19 pandemic stresses the need for widely available diagnostic tests for the presence of SARS-CoV-2 in individuals. Due to the limited availability of vaccines, diagnostic assays which are cheap, easy-to-use at the point-of-need, reliable and fast, are currently the only way to control the pandemic situation. Here we present a diagnostic assay for the detection of pathogen-specific nucleic acids based on changes of the magnetic response of magnetic nanoparticles: The target-mediated hybridization of modified nanoparticles leads to an increase in the hydrodynamic radius. This resulting change in the magnetic behaviour in an ac magnetic field can be measured via magnetic particle spectroscopy (MPS), providing a viable tool for the accurate detection of target nucleic acids. In this work we show that single stranded DNA can be detected in a concentration-dependent manner by these means. In addition to detecting synthetic DNA with an arbitrary sequence in a concentration down to 500 pM, we show that RNA and SARS-CoV-2-specific DNA as well as saliva as a sample medium can be used for an accurate assay. These proof-of-principle experiments show the potential of MPS based assays for the reliable and fast diagnostics of pathogens like SARS-CoV-2 in a point-of-need fashion without the need of complex sample preparation.
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Affiliation(s)
- Enja Laureen Rösch
- Institute for Electrical Measurement Science and Fundamental Electrical Engineering and Laboratory for Emerging Nanometrology (LENA), TU Braunschweig, Hans-Sommer-Str. 66, Braunschweig, 38106, Germany
| | - Jing Zhong
- Institute for Electrical Measurement Science and Fundamental Electrical Engineering and Laboratory for Emerging Nanometrology (LENA), TU Braunschweig, Hans-Sommer-Str. 66, Braunschweig, 38106, Germany
| | - Aidin Lak
- Institute for Electrical Measurement Science and Fundamental Electrical Engineering and Laboratory for Emerging Nanometrology (LENA), TU Braunschweig, Hans-Sommer-Str. 66, Braunschweig, 38106, Germany
| | - Zhe Liu
- Institute of Applied Physics, TU Braunschweig, Mendelssohnstraße 2, 38106, Braunschweig, Germany
| | - Markus Etzkorn
- Institute of Applied Physics, TU Braunschweig, Mendelssohnstraße 2, 38106, Braunschweig, Germany
| | - Meinhard Schilling
- Institute for Electrical Measurement Science and Fundamental Electrical Engineering and Laboratory for Emerging Nanometrology (LENA), TU Braunschweig, Hans-Sommer-Str. 66, Braunschweig, 38106, Germany
| | - Frank Ludwig
- Institute for Electrical Measurement Science and Fundamental Electrical Engineering and Laboratory for Emerging Nanometrology (LENA), TU Braunschweig, Hans-Sommer-Str. 66, Braunschweig, 38106, Germany
| | - Thilo Viereck
- Institute for Electrical Measurement Science and Fundamental Electrical Engineering and Laboratory for Emerging Nanometrology (LENA), TU Braunschweig, Hans-Sommer-Str. 66, Braunschweig, 38106, Germany
| | - Birka Lalkens
- Institute of Semiconductor Technology and Laboratory for Emerging Nanometrology (LENA), TU Braunschweig, Langer Kamp 6a/b, 38106, Braunschweig, Germany.
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5
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Rosławska A, Merino P, Leon CC, Grewal A, Etzkorn M, Kuhnke K, Kern K. Gigahertz Frame Rate Imaging of Charge-Injection Dynamics in a Molecular Light Source. Nano Lett 2021; 21:4577-4583. [PMID: 34038142 PMCID: PMC8193635 DOI: 10.1021/acs.nanolett.1c00328] [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] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/22/2021] [Indexed: 06/12/2023]
Abstract
Light sources on the scale of single molecules can be addressed and characterized at their proper sub-nanometer scale by scanning tunneling microscopy-induced luminescence (STML). Such a source can be driven by defined short charge pulses while the luminescence is detected with sub-nanosecond resolution. We introduce an approach to concurrently image the molecular emitter, which is based on an individual defect, with its local environment along with its luminescence dynamics at a resolution of a billion frames per second. The observed dynamics can be assigned to the single electron capture occurring in the low-nanosecond regime. While the emitter's location on the surface remains fixed, the scanning of the tip modifies the energy landscape for charge injection into the defect. The principle of measurement is extendable to fundamental processes beyond charge transfer, like exciton diffusion.
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Affiliation(s)
- Anna Rosławska
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Université
de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Pablo Merino
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Instituto
de Ciencia de Materiales de Madrid, CSIC, E-28049 Madrid, Spain
- Instituto
de Física Fundamental, CSIC, E-28006 Madrid, Spain
| | | | - Abhishek Grewal
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Markus Etzkorn
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Institut
für Angewandte Physik, TU Braunschweig, D-38106 Braunschweig, Germany
| | - Klaus Kuhnke
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Klaus Kern
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Institut
de Physique, École Polytechnique Fédérale de
Lausanne, CH-1015 Lausanne, Switzerland
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6
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Senkpiel J, Klöckner JC, Etzkorn M, Dambach S, Kubala B, Belzig W, Yeyati AL, Cuevas JC, Pauly F, Ankerhold J, Ast CR, Kern K. Dynamical Coulomb Blockade as a Local Probe for Quantum Transport. Phys Rev Lett 2020; 124:156803. [PMID: 32357030 DOI: 10.1103/physrevlett.124.156803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
Quantum fluctuations are imprinted with valuable information about transport processes. Experimental access to this information is possible, but challenging. We introduce the dynamical Coulomb blockade (DCB) as a local probe for fluctuations in a scanning tunneling microscope (STM) and show that it provides information about the conduction channels. In agreement with theoretical predictions, we find that the DCB disappears in a single-channel junction with increasing transmission following the Fano factor, analogous to what happens with shot noise. Furthermore we demonstrate local differences in the DCB expected from changes in the conduction channel configuration. Our experimental results are complemented by ab initio transport calculations that elucidate the microscopic nature of the conduction channels in our atomic-scale contacts. We conclude that probing the DCB by STM provides a technique complementary to shot noise measurements for locally resolving quantum transport characteristics.
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Affiliation(s)
- Jacob Senkpiel
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Jan C Klöckner
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Markus Etzkorn
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Simon Dambach
- Institut für Komplexe Quantensysteme and IQST, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Björn Kubala
- Institut für Komplexe Quantensysteme and IQST, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Wolfgang Belzig
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Alfredo Levy Yeyati
- Departamento de Física Teórica de la Materia Condensada, Condensed Matter Physics Center (IFIMAC), and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Juan Carlos Cuevas
- Departamento de Física Teórica de la Materia Condensada, Condensed Matter Physics Center (IFIMAC), and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Fabian Pauly
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Joachim Ankerhold
- Institut für Komplexe Quantensysteme and IQST, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Christian R Ast
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Klaus Kern
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
- Institut de Physique, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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7
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Hötger D, Etzkorn M, Morchutt C, Wurster B, Dreiser J, Stepanow S, Grumelli D, Gutzler R, Kern K. Stability of metallo-porphyrin networks under oxygen reduction and evolution conditions in alkaline media. Phys Chem Chem Phys 2019; 21:2587-2594. [PMID: 30657498 DOI: 10.1039/c8cp07463a] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Transition metal atoms stabilised by organic ligands or as oxides exhibit promising catalytic activity for the electrocatalytic reduction and evolution of oxygen. Built-up from earth-abundant elements, they offer affordable alternatives to precious-metal based catalysts for application in fuel cells and electrolysers. For the understanding of a catalyst's activity, insight into its structure on the atomic scale is of highest importance, yet commonly challenging to experimentally access. Here, the structural integrity of a bimetallic iron tetrapyridylporphyrin with co-adsorbed cobalt electrocatalyst on Au(111) is investigated using scanning tunneling microscopy and X-ray absorption spectroscopy. Topographic and spectroscopic characterization reveals structural changes of the molecular coordination network after oxygen reduction, and its decomposition and transformation into catalytically active Co/Fe (oxyhydr)oxide during oxygen evolution. The data establishes a structure-property relationship for the catalyst as a function of electrochemical potential and, in addition, highlights how the reaction direction of electrochemical interconversion between molecular oxygen and hydroxyl anions can have very different effects on the catalyst's structure.
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Affiliation(s)
- Diana Hötger
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany.
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8
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Hötger D, Abufager P, Morchutt C, Alexa P, Grumelli D, Dreiser J, Stepanow S, Gambardella P, Busnengo HF, Etzkorn M, Gutzler R, Kern K. On-surface transmetalation of metalloporphyrins. Nanoscale 2018; 10:21116-21122. [PMID: 30406233 DOI: 10.1039/c8nr04786c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Increasing the complexity of 2D metal-organic networks has led to the fabrication of structures with interesting magnetic and catalytic properties. However, increasing complexity by providing different coordination environments for different metal types imposes limitations on their synthesis if the controlled placement of one metal type into one coordination environment is desired. Whereas metal insertion into free-base porphyrins at the vacuum/solid interface has been thoroughly studied, providing detailed insight into the mechanisms at play, the chemical interaction of a metal atom with a metallated porphyrin is rarely investigated. Herein, the breadth of metalation reactions is augmented towards the metal exchange of a metalloporphyrin through the deliberate addition of atomic metal centers. The cation of Fe(ii)-tetraphenylporphyrins can be replaced by Co in a redox transmetalation-like reaction on a Au(111) surface. Likewise, Cu can be replaced by Co. The reverse reaction does not occur, i.e. Fe does not replace Co in the porphyrin. This non-reversible exchange is investigated in detail by X-ray absorption spectroscopy complemented by scanning tunneling microscopy. Density functional theory illuminates possible reaction pathways and leads to the conclusion that the transmetalation proceeds through the adsorption of initially metallic (neutral) Co onto the porphyrin and the expulsion of Fe towards the surface accompanied by Co insertion. Our findings have important implications for the fabrication of porphyrin layers on surfaces when subject to the additional deposition of metals. Mixed-metal porphyrin layers can be fabricated by design in a solvent-free process, but conversely care must be taken that the transmetalation does not proceed as an undesired side reaction.
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Affiliation(s)
- Diana Hötger
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany.
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9
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Rosławska A, Merino P, Große C, Leon CC, Gunnarsson O, Etzkorn M, Kuhnke K, Kern K. Single Charge and Exciton Dynamics Probed by Molecular-Scale-Induced Electroluminescence. Nano Lett 2018; 18:4001-4007. [PMID: 29799760 DOI: 10.1021/acs.nanolett.8b01489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Excitons and their constituent charge carriers play the central role in electroluminescence mechanisms determining the ultimate performance of organic optoelectronic devices. The involved processes and their dynamics are often studied with time-resolved techniques limited by spatial averaging that obscures the properties of individual electron-hole pairs. Here, we overcome this limit and characterize single charge and exciton dynamics at the nanoscale by using time-resolved scanning tunneling microscopy-induced luminescence (TR-STML) stimulated with nanosecond voltage pulses. We use isolated defects in C60 thin films as a model system into which we inject single charges and investigate the formation dynamics of a single exciton. Tunable hole and electron injection rates are obtained from a kinetic model that reproduces the measured electroluminescent transients. These findings demonstrate that TR-STML can track dynamics at the quantum limit of single charge injection and can be extended to other systems and materials important for nanophotonic devices.
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Affiliation(s)
- Anna Rosławska
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Pablo Merino
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Christoph Große
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Christopher C Leon
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Olle Gunnarsson
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Markus Etzkorn
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Klaus Kuhnke
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Klaus Kern
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
- Institut de Physique , École Polytechnique Fédérale de Lausanne , 1015 Lausanne , Switzerland
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10
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Jäck B, Senkpiel J, Etzkorn M, Ankerhold J, Ast CR, Kern K. Quantum Brownian Motion at Strong Dissipation Probed by Superconducting Tunnel Junctions. Phys Rev Lett 2017; 119:147702. [PMID: 29053289 DOI: 10.1103/physrevlett.119.147702] [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] [Received: 01/15/2017] [Indexed: 06/07/2023]
Abstract
We have investigated the phase dynamics of a superconducting tunnel junction at ultralow temperatures in the presence of high damping, where the interaction with environmental degrees of freedom represents the leading energy scale. In this regime, theory predicts the dynamics to follow a generalization of the classical Smoluchowski description, the quantum Smoluchowski equation, thus, exhibiting overdamped quantum Brownian motion characteristics. For this purpose, we have performed current-biased measurements on the small-capacitance Josephson junction of a scanning tunneling microscope placed in a low impedance environment at milli-Kelvin temperatures. We can describe our experimental findings with high accuracy by using a quantum phase diffusion model based on the quantum Smoluchowski equation. In this way we experimentally demonstrate that overdamped quantum systems follow quasiclassical dynamics with significant quantum effects as the leading corrections.
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Affiliation(s)
- Berthold Jäck
- Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
| | - Jacob Senkpiel
- Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
| | - Markus Etzkorn
- Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
| | - Joachim Ankerhold
- Institut für Komplexe Quantensysteme and IQST, Universität Ulm, 89069 Ulm, Germany
| | - Christian R Ast
- Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
| | - Klaus Kern
- Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
- Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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11
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Ast CR, Jäck B, Senkpiel J, Eltschka M, Etzkorn M, Ankerhold J, Kern K. Sensing the quantum limit in scanning tunnelling spectroscopy. Nat Commun 2016; 7:13009. [PMID: 27708282 PMCID: PMC5059741 DOI: 10.1038/ncomms13009] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [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: 02/25/2016] [Accepted: 08/25/2016] [Indexed: 11/12/2022] Open
Abstract
The tunnelling current in scanning tunnelling spectroscopy (STS) is typically and often implicitly modelled by a continuous and homogeneous charge flow. If the charging energy of a single-charge quantum sufficiently exceeds the thermal energy, however, the granularity of the current becomes non-negligible. In this quantum limit, the capacitance of the tunnel junction mediates an interaction of the tunnelling electrons with the surrounding electromagnetic environment and becomes a source of noise itself, which cannot be neglected in STS. Using a scanning tunnelling microscope operating at 15 mK, we show that we operate in this quantum limit, which determines the ultimate energy resolution in STS. The P(E)-theory describes the probability for a tunnelling electron to exchange energy with the environment and can be regarded as the energy resolution function. We experimentally demonstrate this effect with a superconducting aluminium tip and a superconducting aluminium sample, where it is most pronounced. The tunnelling current in scanning tunnelling spectroscopy has often been treated by a continuous charge flow, which lacks proper treatment of charge quantization. Here, Ast et al. unveil the effects of granularity in the tunnelling current at extremely low temperatures by including P(E) theory, thereby reaching the quantum limit in scanning tunnelling spectroscopy.
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Affiliation(s)
- Christian R Ast
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Berthold Jäck
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Jacob Senkpiel
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Matthias Eltschka
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Markus Etzkorn
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Joachim Ankerhold
- Institut für Komplexe Quantensysteme and IQST, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Klaus Kern
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany.,Institut de Physique, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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12
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Vijayaraghavan S, Auwärter W, Ecija D, Seufert K, Rusponi S, Houwaart T, Sautet P, Bocquet ML, Thakur P, Stepanow S, Schlickum U, Etzkorn M, Brune H, Barth JV. Restoring the Co magnetic moments at interfacial Co-porphyrin arrays by site-selective uptake of iron. ACS Nano 2015; 9:3605-3616. [PMID: 25856066 DOI: 10.1021/nn507346x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Magnetochemistry recently emerged as a promising approach to control addressable spin arrays on surfaces. Here we report on the binding, spatial ordering, and magnetic properties of Fe on a highly regular Co-tetraphenylporphyrin (Co-TPP) template and highlight how the Fe controls the magnetism of the Co centers. As evidenced by scanning tunneling microscopy (STM) single Fe atoms attach to the saddle-shape conformers site-selectively in a unique coordination environment offered through a heptamer defined by the Co-N-C-C-C-N cyclic subunit. While the magnetic moment of Co is quenched for bare Co-TPP/Ag(111), the Fe presence revives it. Our X-ray magnetic circular dichroism (XMCD) experiments, complemented by density functional theory (DFT) calculations, evidence a ferromagnetic coupling between the Fe and the Co center concomitant with a complex charge redistribution involving the porphyrin ligand. Thus, we demonstrate an unusual metalloporphyrin coordination geometry that opens pathways to spatially order and engineer magnetic moments in surface-based nanostructures.
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Affiliation(s)
| | - Willi Auwärter
- †Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
| | - David Ecija
- †Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
| | - Knud Seufert
- †Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
| | - Stefano Rusponi
- ‡Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Torsten Houwaart
- §Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, F-69364 Cedex 07 Lyon, France
| | - Philippe Sautet
- §Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, F-69364 Cedex 07 Lyon, France
| | - Marie-Laure Bocquet
- §Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, F-69364 Cedex 07 Lyon, France
| | - Pardeep Thakur
- ⊥European Synchrotron Radiation Facility (ESRF), B.P. 220, Grenoble Cedex F-38043, France
| | - Sebastian Stepanow
- ∥Department of Materials, ETH Zürich, Hönggerbergring 64, CH-8093 Zürich, Switzerland
| | - Uta Schlickum
- ‡Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- #Max Planck Institut für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Markus Etzkorn
- ‡Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- #Max Planck Institut für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Harald Brune
- ‡Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Johannes V Barth
- †Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
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13
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Dubout Q, Donati F, Wäckerlin C, Calleja F, Etzkorn M, Lehnert A, Claude L, Gambardella P, Brune H. Controlling the spin of co atoms on pt(111) by hydrogen adsorption. Phys Rev Lett 2015; 114:106807. [PMID: 25815958 DOI: 10.1103/physrevlett.114.106807] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Indexed: 06/04/2023]
Abstract
We investigate the effect of H adsorption on the magnetic properties of individual Co atoms on Pt(111) with scanning tunneling microscopy. For pristine Co atoms, we detect no inelastic features in the tunnel spectra. Conversely, CoH and CoH2 show a number of low-energy vibrational features in their differential conductance identified by isotope substitution. Only the fcc-adsorbed species present conductance steps of magnetic origin, with a field splitting identifying their effective spin as Seff=2 for CoH and 3/2 for CoH2. The exposure to H2 and desorption through tunnel electrons allow the reversible control of the spin in half-integer steps. Because of the presence of the surface, the hydrogen-induced spin increase is opposite to the spin sequence of CoHn molecules in the gas phase.
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Affiliation(s)
- Q Dubout
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - F Donati
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - C Wäckerlin
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - F Calleja
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Calle Faraday 9, Campus Cantoblanco, E-28049 Madrid, Spain
| | - M Etzkorn
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - A Lehnert
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - L Claude
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - P Gambardella
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
- Department of Materials, ETH Zürich, Hönggerbergring 64, CH-8093 Zürich, Switzerland
| | - H Brune
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
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14
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Eltschka M, Jäck B, Assig M, Kondrashov OV, Skvortsov MA, Etzkorn M, Ast CR, Kern K. Probing absolute spin polarization at the nanoscale. Nano Lett 2014; 14:7171-7174. [PMID: 25423049 DOI: 10.1021/nl5037947] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Probing absolute values of spin polarization at the nanoscale offers insight into the fundamental mechanisms of spin-dependent transport. Employing the Zeeman splitting in superconducting tips (Meservey-Tedrow-Fulde effect), we introduce a novel spin-polarized scanning tunneling microscopy that combines the probing capability of the absolute values of spin polarization with precise control at the atomic scale. We utilize our novel approach to measure the locally resolved spin polarization of magnetic Co nanoislands on Cu(111). We find that the spin polarization is enhanced by 65% when increasing the width of the tunnel barrier by only 2.3 Å due to the different decay of the electron orbitals into vacuum.
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Affiliation(s)
- Matthias Eltschka
- Max-Planck-Institut für Festkörperforschung , 70569 Stuttgart, Germany
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15
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Große C, Kabakchiev A, Lutz T, Froidevaux R, Schramm F, Ruben M, Etzkorn M, Schlickum U, Kuhnke K, Kern K. Dynamic control of plasmon generation by an individual quantum system. Nano Lett 2014; 14:5693-5697. [PMID: 25181332 DOI: 10.1021/nl502413k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Controlling light on the nanoscale in a similar way as electric currents has the potential to revolutionize the exchange and processing of information. Although light can be guided on this scale by coupling it to plasmons, that is, collective electron oscillations in metals, their local electronic control remains a challenge. Here, we demonstrate that an individual quantum system is able to dynamically gate the electrical plasmon generation. Using a single molecule in a double tunnel barrier between two electrodes we show that this gating can be exploited to monitor fast changes of the quantum system itself and to realize a single-molecule plasmon-generating field-effect transistor operable in the gigahertz range. This opens new avenues toward atomic scale quantum interfaces bridging nanoelectronics and nanophotonics.
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Affiliation(s)
- Christoph Große
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
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16
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Ivanina AV, Beniash E, Etzkorn M, Meyers TB, Ringwood AH, Sokolova IM. Short-term acute hypercapnia affects cellular responses to trace metals in the hard clams Mercenaria mercenaria. Aquat Toxicol 2013; 140-141:123-133. [PMID: 23796537 DOI: 10.1016/j.aquatox.2013.05.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 05/21/2013] [Accepted: 05/25/2013] [Indexed: 06/02/2023]
Abstract
Estuarine and coastal habitats experience large fluctuations of environmental factors such as temperature, salinity, partial pressure of CO2 ( [Formula: see text] ) and pH; they also serve as the natural sinks for trace metals. Benthic filter-feeding organisms such as bivalves are exposed to the elevated concentrations of metals in estuarine water and sediments that can strongly affect their physiology. The effects of metals on estuarine organisms may be exacerbated by other environmental factors. Thus, a decrease in pH caused by high [Formula: see text] (hypercapnia) can modulate the effects of trace metals by affecting metal bioavailability, accumulation or binding. To better understand the cellular mechanisms of interactions between [Formula: see text] and trace metals in marine bivalves, we exposed isolated mantle cells of the hard clams (Mercenaria mercenaria) to different levels of [Formula: see text] (0.05, 1.52 and 3.01 kPa) and two major trace metal pollutants - cadmium (Cd) and copper (Cu). Elevated [Formula: see text] resulted in a decrease in intracellular pH (pHi) of the isolated mantle cells from 7.8 to 7.4. Elevated [Formula: see text] significantly but differently affected the trace metal accumulation by the cells. Cd uptake was suppressed at elevated [Formula: see text] levels while Cu accumulation has greatly accelerated under hypercapnic conditions. Interestingly, at higher extracellular Cd levels, labile intracellular Cd(2+) concentration remained the same, while intracellular levels of free Zn(2+) increased suggesting that Cd(2+) substitutes bound Zn(2+) in these cells. In contrast, Cu exposure did not affect intracellular Zn(2+) but led to a profound increase in the intracellular levels of labile Cu(2+) and Fe(2+). An increase in the extracellular concentrations of Cd and Cu led to the elevated production of reactive oxygen species under the normocapnic conditions (0.05 kPa [Formula: see text] ); surprisingly, this effect was mitigated in hypercapnia (1.52 and 3.01 kPa). Overall, our data reveal complex and metal-specific interactions between the cellular effects of trace metals and [Formula: see text] in clams and indicate that variations in environmental [Formula: see text] may modulate the biological effects of trace metals in marine organisms.
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Affiliation(s)
- Anna V Ivanina
- Department of Biology, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA
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17
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Assig M, Etzkorn M, Enders A, Stiepany W, Ast CR, Kern K. A 10 mK scanning tunneling microscope operating in ultra high vacuum and high magnetic fields. Rev Sci Instrum 2013; 84:033903. [PMID: 23556826 DOI: 10.1063/1.4793793] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We present design and performance of a scanning tunneling microscope (STM) that operates at temperatures down to 10 mK providing ultimate energy resolution on the atomic scale. The STM is attached to a dilution refrigerator with direct access to an ultra high vacuum chamber allowing in situ sample preparation. High magnetic fields of up to 14 T perpendicular and up to 0.5 T parallel to the sample surface can be applied. Temperature sensors mounted directly at the tip and sample position verified the base temperature within a small error margin. Using a superconducting Al tip and a metallic Cu(111) sample, we determined an effective temperature of 38 ± 1 mK from the thermal broadening observed in the tunneling spectra. This results in an upper limit for the energy resolution of ΔE = 3.5 kBT = 11.4 ± 0.3 μeV. The stability between tip and sample is 4 pm at a temperature of 15 mK as demonstrated by topography measurements on a Cu(111) surface.
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Affiliation(s)
- Maximilian Assig
- Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
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18
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Papagno M, Rusponi S, Sheverdyaeva PM, Vlaic S, Etzkorn M, Pacilé D, Moras P, Carbone C, Brune H. Large band gap opening between graphene Dirac cones induced by Na adsorption onto an Ir superlattice. ACS Nano 2012; 6:199-204. [PMID: 22136502 DOI: 10.1021/nn203841q] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We investigate the effects of Na adsorption on the electronic structure of bare and Ir cluster superlattice-covered epitaxial graphene on Ir(111) using angle-resolved photoemission spectroscopy and scanning tunneling microscopy. At Na saturation coverage, a massive charge migration from sodium atoms to graphene raises the graphene Fermi level by ~1.4 eV relative to its neutrality point. We find that Na is adsorbed on top of the graphene layer, and when coadsorbed onto an Ir cluster superlattice, it results in the opening of a large band gap of Δ(Na/Ir/G) = 740 meV, comparable to the one of Ge and with preserved high group velocity of the charge carriers.
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Affiliation(s)
- Marco Papagno
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste, Italy.
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19
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Kane CM, Meyers TB, Yu X, Gerken M, Etzkorn M. Bergman Cyclization of Fluorinated Benzo-Fused Enediynes to Naphthalene Derivatives: Syntheses and Structures. European J Org Chem 2011. [DOI: 10.1002/ejoc.201001747] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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20
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Rusponi S, Papagno M, Moras P, Vlaic S, Etzkorn M, Sheverdyaeva PM, Pacilé D, Brune H, Carbone C. Highly anisotropic Dirac cones in epitaxial graphene modulated by an island superlattice. Phys Rev Lett 2010; 105:246803. [PMID: 21231546 DOI: 10.1103/physrevlett.105.246803] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 10/13/2010] [Indexed: 05/30/2023]
Abstract
We present a new method to engineer the charge carrier mobility and its directional asymmetry in epitaxial graphene by using metal cluster superlattices self-assembled onto the moiré pattern formed by graphene on Ir(111). Angle-resolved photoemission spectroscopy reveals threefold symmetry in the band structure associated with strong renormalization of the electron group velocity close to the Dirac point giving rise to highly anisotropic Dirac cones. We further find that the cluster superlattice also affects the spectral-weight distribution of the carbon bands as well as the electronic gaps between graphene states.
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Affiliation(s)
- S Rusponi
- Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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21
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Kachlan RM, Ruble MC, Timmerman JC, Etzkorn M, Jones DS. syn-Dispiro-[1,3-dioxolane-2,17'-penta-cyclo-[12.2.1.1.0.0]octa-decane-18',2''-[1,3]dioxolane]-7',15'-diene. Acta Crystallogr Sect E Struct Rep Online 2010; 66:o2880. [PMID: 21589061 PMCID: PMC3009060 DOI: 10.1107/s1600536810041565] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 10/14/2010] [Indexed: 11/10/2022]
Abstract
The title compound, C(22)H(28)O(4), is composed of a central octa-decane ring and two spiro-[bicyclo-[2.2.1]hept[2]ene-7,2'-[1,3]dioxolane] units. This polycycle has pseudo twofold symmetry and the central cyclo-octane ring has a distorted boat configuration.
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Affiliation(s)
- Rulla M. Kachlan
- Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA
| | - Macey C. Ruble
- Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA
| | - Jacob C. Timmerman
- Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA
| | - Markus Etzkorn
- Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA
| | - Daniel S. Jones
- Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA
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22
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Loth S, Etzkorn M, Lutz CP, Eigler DM, Heinrich AJ. Measurement of Fast Electron Spin Relaxation Times with Atomic Resolution. Science 2010; 329:1628-30. [DOI: 10.1126/science.1191688] [Citation(s) in RCA: 273] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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23
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Kurochkin IO, Etzkorn M, Buchwalter D, Leamy L, Sokolova IM. Top-down control analysis of the cadmium effects on molluscan mitochondria and the mechanisms of cadmium-induced mitochondrial dysfunction. Am J Physiol Regul Integr Comp Physiol 2010; 300:R21-31. [PMID: 20844261 DOI: 10.1152/ajpregu.00279.2010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cadmium (Cd) is a toxic metal and an important environmental pollutant that can strongly affect mitochondrial function and bioenergetics in animals. We investigated the mechanisms of Cd action on mitochondrial function of a marine mollusk (the eastern oyster Crassostrea virginica) by performing a top-down control analysis of the three major mitochondrial subsystems (substrate oxidation, proton leak, and phosphorylation). Our results showed that the substrate oxidation and proton leak subsystems are the main targets for Cd toxicity in oyster mitochondria. Exposure to 12.5 μM Cd strongly inhibited the substrate oxidation subsystem and stimulated the proton conductance across the inner mitochondrial membrane. Proton conductance was also elevated and substrate oxidation inhibited by Cd in the presence of a mitochondrially targeted antioxidant, MitoVitE, indicating that Cd effects on these subsystems were to a large extent ROS independent. Cd did not affect the kinetics of the phosphorylation system, indicating that it has negligible effects on F₁, F(O) ATP synthase and/or the adenine nucleotide transporter in oyster mitochondria. Cd exposure altered the patterns of control over mitochondrial respiration, increasing the degree of control conferred by the substrate oxidation subsystem, especially in resting (state 4) mitochondria. Taken together, these data suggest that Cd-induced decrease of mitochondrial efficiency and ATP production are predominantly driven by the high sensitivity of substrate oxidation and proton leak subsystems to this metal.
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Affiliation(s)
- Ilya O Kurochkin
- Dept. of Biology, Univ. of North Carolina at Charlotte, 28223, USA
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24
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Tenbusch ME, Brooker MD, Timmerman JC, Jones DS, Etzkorn M. anti-1′,6′,7′,8′,9′,14′,15′,16′-Octachlorodispiro[1,3-dioxolane-2,17′-pentacyclo[12.2.1.1 6,9.0 2,13.0 5,10]octadecane-18′,2′′-1,3-dioxolane]-7′,15′-diene. Acta Crystallogr Sect E Struct Rep Online 2010; 66:o1882. [PMID: 21588218 PMCID: PMC3007477 DOI: 10.1107/s1600536810024669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 06/23/2010] [Indexed: 11/22/2022]
Abstract
The title compound, C22H20Cl8O4, was prepared as part of the synthesis of precursors for the preparation of fluorinated molecular tweezers. The molecule sits on an inversion center, thus requiring that the cyclooctane ring adopt a chair conformation.
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25
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Etzkorn M, Timmerman JC, Brooker MD, Yu X, Gerken M. Preparation, structures and preliminary host-guest studies of fluorinated syn-bis-quinoxaline molecular tweezers. Beilstein J Org Chem 2010; 6:39. [PMID: 20502656 PMCID: PMC2874330 DOI: 10.3762/bjoc.6.39] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Accepted: 03/23/2010] [Indexed: 01/25/2023] Open
Abstract
A series of polycyclic frameworks with fluorinated syn-facial quinoxaline sidewalls has been prepared as potential molecular tweezers for electron-rich guest compounds. Our synthetic route to the cyclooctadiene-derived scaffolds 16a-d takes advantage of the facile isolation of a novel spirocyclic precursor 9b with the crucial syn-orientation of its two alkene moieties. The crystal structure of 16c displays two features typical of a molecular tweezer: inclusion of a solvent molecule in the molecular cleft and self-association of the self-complementary scaffolds. Furthermore, host-guest NMR studies of compound 16c in solution show chemical exchange between the unbound and bound electron-rich guest, N,N,N',N'-tetramethyl-p-phenylenediamine.
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Affiliation(s)
- Markus Etzkorn
- Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA.
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26
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Gidaly MP, Harris AD, Amado-Sierra MDRI, Jones DS, Etzkorn M. anti-Tricyclo-[4.2.1.1]deca-3,7-diene-9,10-dione. Acta Crystallogr Sect E Struct Rep Online 2009; 65:o729. [PMID: 21582463 PMCID: PMC2969011 DOI: 10.1107/s1600536809005844] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [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: 12/31/2008] [Accepted: 02/18/2009] [Indexed: 11/10/2022]
Abstract
The title compound, C(10)H(8)O(2), is a precursor to an unusual bis-homoaromatic dication and to heterodiamantanes and other oxa-cage compounds. Two independent mol-ecules, each of which is situated on a center of symmetry, comprise the unit cell. Both mol-ecules are in nearly identical chair conformations.
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Affiliation(s)
- Matthew P Gidaly
- Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC 28223, USA
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27
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Harris AD, Baucom AD, Sierra MDRIA, Jones DS, Etzkorn M. anti-Tricyclo-[4.2.1.1]deca-3,7-diene-9-endo,10-endo-diol. Acta Crystallogr Sect E Struct Rep Online 2008; 64:o2270. [PMID: 21581251 PMCID: PMC2959889 DOI: 10.1107/s1600536808035423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [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: 09/30/2008] [Accepted: 10/29/2008] [Indexed: 11/10/2022]
Abstract
The title compound, C(10)H(12)O(2), was synthesized as a candidate for further functionalization. The asymmetric unit comprises two independent mol-ecules, both of which are situated on a center of symmetry. Both mol-ecules are involved in a network of hydrogen bonding, with each alcohol group participating in one hydrogen bond as a donor and in a second hydrogen bond as an acceptor.
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Affiliation(s)
- Andria D Harris
- Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA
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28
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Etzkorn M, Aniszfeld R, Li T, Buchholz H, Rasul G, Prakash GKS, Olah GA. 1-Oxoniaadamantane (Eur. J. Org. Chem. 27/2008). European J Org Chem 2008. [DOI: 10.1002/ejoc.200890072] [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: 11/06/2022]
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Yambo CL, Williams PS, Au DJ, Jones DS, Etzkorn M. cis-9,10-Bis(bromo-meth-yl)-1,4,5,8-tetra-oxadeca-lin. Acta Crystallogr Sect E Struct Rep Online 2008; 64:o1172. [PMID: 21202679 PMCID: PMC2961570 DOI: 10.1107/s1600536808015377] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2007] [Accepted: 05/21/2008] [Indexed: 11/25/2022]
Abstract
The title compound, C8H12Br2O4, is a bicyclic ketal in which the two six-membered rings are cis to one another and assume a double-chair conformation. A crystallographic twofold axis bisects the molecule.
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Affiliation(s)
- Courtney L Yambo
- Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA
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Tang WX, Zhang Y, Tudosa I, Prokop J, Etzkorn M, Kirschner J. Large wave vector spin waves and dispersion in two monolayer fe on w(110). Phys Rev Lett 2007; 99:087202. [PMID: 17930976 DOI: 10.1103/physrevlett.99.087202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Indexed: 05/25/2023]
Abstract
We present the first surface spin-wave (SW) dispersion measurements up to the surface Brillouin zone boundary of a two monolayer Fe film on W(110) by using spin-polarized electron energy loss spectroscopy. Pronounced features of SW peaks are observed in the spectra at room temperature. We found that the SW energies in the Fe film are strongly reduced compared to spin waves in bulk Fe and to theoretical predictions. Our results suggest that this reduction is caused by the reduction of exchange interaction within the 2 ML Fe on W(110) as compared to bulk Fe.
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Affiliation(s)
- W X Tang
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120, Halle, Germany.
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Etzkorn M. Organofluorine Chemistry By Kenji Uneyama (Okayama University, Japan). Blackwell Publishing, Ltd.: Oxford. 2006. x + 340 pp. $179.99. ISBN 1-4051-2561-6. J Am Chem Soc 2006. [DOI: 10.1021/ja0697976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Haiges R, Wagner R, Boatz JA, Yousufuddin M, Etzkorn M, Prakash GKS, Christe KO, Chapman RD, Welker MF, Kreutzberger CB. Preparation, Characterization, and Crystal Structures of the SO3NHF− and SO3NF2− Ions. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200601020] [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: 11/12/2022]
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Haiges R, Wagner R, Boatz JA, Yousufuddin M, Etzkorn M, Prakash GKS, Christe KO, Chapman RD, Welker MF, Kreutzberger CB. Preparation, Characterization, and Crystal Structures of the SO3NHF− and SO3NF2− Ions. Angew Chem Int Ed Engl 2006; 45:5179-84. [PMID: 16927336 DOI: 10.1002/anie.200601020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ralf Haiges
- Loker Research Institute and Department of Chemistry, University of Southern California, Los Angeles, CA 90089-1661, USA.
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Ibach H, Etzkorn M, Kirschner J. Electron spectrometers for inelastic scattering from magnetic surface excitations. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2425] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [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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Affiliation(s)
- G K Surya Prakash
- Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, 837 Bloom Walk, Los Angeles, CA 90034-1661, USA.
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Vollmer R, Etzkorn M, Kumar PSA, Ibach H, Kirschner J. Spin-polarized electron energy loss spectroscopy of high energy, large wave vector spin waves in ultrathin fcc Co films on Cu(001). Phys Rev Lett 2003; 91:147201. [PMID: 14611549 DOI: 10.1103/physrevlett.91.147201] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2003] [Indexed: 05/23/2023]
Abstract
The realm of high energy, large wave vector spin waves in ultrathin films and at surfaces is unexplored because a suitable method was not available up to now. We present experimental data for an 8 ML thick Co film deposited on Cu(001) which show that spin-polarized electron energy loss spectroscopy can be used to measure spin-wave dispersion curves of ultrathin ferromagnetic films up to the surface Brillouin zone boundary.
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Affiliation(s)
- R Vollmer
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
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Prakash GKS, Etzkorn M, Olah GA, Christe KO, Schneider S, Vij A. Triphenylmethyldifluoramine: a stable reagent for the synthesis of gem-bis(difluoramines). Chem Commun (Camb) 2002:1712-3. [PMID: 12196962 DOI: 10.1039/b203811k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The conversion of ketones into geminal bis(difluoramines) can be achieved under mild two-phase reaction conditions by employing triphenylmethyldifluoramine as an in situ source of difluoramine.
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Affiliation(s)
- G K Surya Prakash
- Loker Hydrocarbon Research Institute, Department of Chemistry, University of Southern California, University Park, Los Angeles, CA 90089-1661, USA.
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Olah GA, Mathew T, Marinez ER, Esteves PM, Etzkorn M, Rasul G, Prakash GK. Acid-catalyzed isomerization of pivalaldehyde to methyl isopropyl ketone via a reactive protosolvated carboxonium ion intermediate. J Am Chem Soc 2001; 123:11556-61. [PMID: 11716708 DOI: 10.1021/ja011253a] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [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
Quantitative rearrangement of pivalaldehyde to methyl isopropyl ketone is observed in acids such as trifluoromethanesulfonic acid, anhydrous HF, and trifluoroethyl alcohol-BF3 but not in trifluoroacetic acid. Studies in a mixture of trifluoroacetic acid and trifluoromethanesulfonic acid show that acids with H(o) < or = -11 are able to carry out complete isomerization. These results and density functional theory calculations at the B3LYP/6-31G level suggest that protonated pivalaldehyde undergoes further protosolvation at higher acidities to a reactive superelectrophilic species resulting in rearrangement. A mechanism for the pivalaldehyde rearrangement to methyl isopropyl ketone in strong protic acids involving a reactive protosolvated superelectrophilic intermediate is suggested. Aspects of the related mechanism of the reaction with isobutane with CO in HF/BF3 medium leading to methyl isopropyl ketone are also discussed.
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Affiliation(s)
- G A Olah
- Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, USA
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Wollenweber M, Etzkorn M, Reinbold J, Wahl F, Voss T, Melder JP, Grund C, Pinkos R, Hunkler D, Keller M, Wörth J, Knothe L, Prinzbach H. [2.2.2.2]/[2.1.1.1]Pagodanes and [1.1.1.1]/[2.2.1.1]/[2.2.2.2]Isopagodanes: Syntheses, Structures, Reactivities − Benzo/Ene- and Benzo/Benzo-Photocycloadditions. European J Org Chem 2000. [DOI: 10.1002/1099-0690(200012)2000:23<3855::aid-ejoc3855>3.0.co;2-a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Surya Prakash GK, Weber K, Olah GA, Weber K, Prinzbach H, Wollenweber M, Etzkorn M, Voss T, Herges R. Long-lived [1.1.1.1]- and [2.2.1.1]-‘Isopagodane’ dications: novel 4C/2e σ-bishomoaromatic dications†. Chem Commun (Camb) 1999. [DOI: 10.1039/a901202h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [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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Etzkorn M, Wahl F, Keller M, Prinzbach H, Barbosa F, Peron V, Gescheidt G, Heinze J, Herges R. [2.2.2.2]Pagodane: Synthesis and Oxidation of Nonclassical Valence-Isomeric 4C/3e and sigma-Bishomoaromatic 4C/2e Ions. J Org Chem 1998; 63:6080-6081. [PMID: 11672224 DOI: 10.1021/jo980892+] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Markus Etzkorn
- Institut für Organische Chemie und Biochemie der Universität, Albert-Ludwigs-Universität, Albertstrasse 21, D-79104 Freiburg, Germany, Institut für Organische Chemie der Universität, St. Johanns-Ring 19, CH-4056 Basel, Switzerland, Institut für Physikalische Chemie der Universität, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Institut für Physikalische Chemie der Universität, Albert-Ludwigs-Universität, Albertstrasse 21, D-79104 Freiburg, Germany, and Institut für Organische Chemie der Universität, Hagenring 10, D-38106 Braunschweig, Germany
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Trifunac AD, Werst DW, Herges R, Neumann H, Prinzbach H, Etzkorn M. (Iso)Pagodane Radical Cations in Liquid Hydrocarbons: “Time-Resolved Fluorescence-Detected Magnetic Resonance” Study of Valence Isomeric Radical Cations. J Am Chem Soc 1996. [DOI: 10.1021/ja961035v] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gescheidt G, Herges R, Neumann H, Heinze J, Wollenweber M, Etzkorn M, Prinzbach H. 4c/3e Radical Cations with Cage-Directed Configurations. ACTA ACUST UNITED AC 1995. [DOI: 10.1002/anie.199510161] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Gescheidt G, Herges R, Neumann H, Heinze J, Wollenweber M, Etzkorn M, Prinzbach H. 4c/3e-Radikalkationen mit Käfig-gesteuerten Konfigurationen. Angew Chem Int Ed Engl 1995. [DOI: 10.1002/ange.19951070922] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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