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Mukkatt I, Nirmala A, Madhavan ND, Shankar S, Deb B, Ajayaghosh A. Ligand-Controlled Electrochromic Diversification with Multilayer Coated Metallosupramolecular Polymer Assemblies. ACS APPLIED MATERIALS & INTERFACES 2021; 13:5245-5255. [PMID: 33470782 DOI: 10.1021/acsami.0c20428] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Designing surface-confined molecular systems capable of expressing changes in functional properties as a result of slight variations in chemical structure under the influence of an external stimulus is of contemporary interest. In this context, we have designed three tetraterpyridine ligands with variations in their core architecture (phenyl vs tetraphenylethynyl vs bithiophene) to create spray-coated electrochromic assemblies of iron(II)-based metallosupramolecular polymer network films on transparent conducting oxide substrates. These assemblies exhibited molecular permeability and spectroelectrochemical properties that are in turn dictated by the ligand structure. Electrochromic films with high coloration efficiencies (up to 1050 cm2/C) and superior optical contrast (up to 76%) with a concomitant color-to-color redox transition were readily achieved. These functional switching elements were integrated into sandwich-type electrochromic cells (CE up to 641 cm2/C) that exhibited high contrast ratios of up to 56%, with attractive ON-OFF ratios, fast switching kinetics, and high operational stability. Every measurable spectroelectrochemical property of the films and devices is an associated function of the ligand structure that coordinates the same metal ion to different extents. While exhibiting a ligand-structure induced differential metal coordination leading to porosity and spectroelectrochemical diversification, these assemblies allow the creation of electrochromic patterns and images by a simple spray-coating technique.
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Affiliation(s)
- Indulekha Mukkatt
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Industrial Estate P.O., Pappanamcode, Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India
| | - Anjali Nirmala
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Industrial Estate P.O., Pappanamcode, Thiruvananthapuram 695019, India
| | - Nayan Dev Madhavan
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Industrial Estate P.O., Pappanamcode, Thiruvananthapuram 695019, India
| | - Sreejith Shankar
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Industrial Estate P.O., Pappanamcode, Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India
| | - Biswapriya Deb
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Industrial Estate P.O., Pappanamcode, Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India
| | - Ayyappanpillai Ajayaghosh
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Industrial Estate P.O., Pappanamcode, Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India
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Pathirathna P, Balla RJ, Jantz DT, Kurapati N, Gramm ER, Leonard KC, Amemiya S. Probing High Permeability of Nuclear Pore Complexes by Scanning Electrochemical Microscopy: Ca 2+ Effects on Transport Barriers. Anal Chem 2019; 91:5446-5454. [PMID: 30907572 PMCID: PMC6535230 DOI: 10.1021/acs.analchem.9b00796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The nuclear pore complex (NPC) solely mediates molecular transport between the nucleus and cytoplasm of a eukaryotic cell to play important biological and biomedical roles. However, it is not well-understood chemically how this biological nanopore selectively and efficiently transports various substances, including small molecules, proteins, and RNAs by using transport barriers that are rich in highly disordered repeats of hydrophobic phenylalanine and glycine intermingled with charged amino acids. Herein, we employ scanning electrochemical microscopy to image and measure the high permeability of NPCs to small redox molecules. The effective medium theory demonstrates that the measured permeability is controlled by diffusional translocation of probe molecules through water-filled nanopores without steric or electrostatic hindrance from hydrophobic or charged regions of transport barriers, respectively. However, the permeability of NPCs is reduced by a low millimolar concentration of Ca2+, which can interact with anionic regions of transport barriers to alter their spatial distributions within the nanopore. We employ atomic force microscopy to confirm that transport barriers of NPCs are dominantly recessed (∼80%) or entangled (∼20%) at the high Ca2+ level in contrast to authentic populations of entangled (∼50%), recessed (∼25%), and "plugged" (∼25%) conformations at a physiological Ca2+ level of submicromolar. We propose a model for synchronized Ca2+ effects on the conformation and permeability of NPCs, where transport barriers are viscosified to lower permeability. Significantly, this result supports a hypothesis that the functional structure of transport barriers is maintained not only by their hydrophobic regions, but also by charged regions.
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Affiliation(s)
- Pavithra Pathirathna
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Ryan J. Balla
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Dylan T. Jantz
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, United States
| | - Niraja Kurapati
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Erin R. Gramm
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Kevin C. Leonard
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, United States
| | - Shigeru Amemiya
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
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Chen R, Najarian AM, Kurapati N, Balla RJ, Oleinick A, Svir I, Amatore C, McCreery RL, Amemiya S. Self-Inhibitory Electron Transfer of the Co(III)/Co(II)-Complex Redox Couple at Pristine Carbon Electrode. Anal Chem 2018; 90:11115-11123. [PMID: 30118206 DOI: 10.1021/acs.analchem.8b03023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Applications of conducting carbon materials for highly efficient electrochemical energy devices require a greater fundamental understanding of heterogeneous electron-transfer (ET) mechanisms. This task, however, is highly challenging experimentally, because an adsorbing carbon surface may easily conceal its intrinsic reactivity through adventitious contamination. Herein, we employ nanoscale scanning electrochemical microscopy (SECM) and cyclic voltammetry to gain new insights into the interplay between heterogeneous ET and adsorption of a Co(III)/Co(II)-complex redox couple at the contamination-free surface of electron-beam-deposited carbon (eC). Specifically, we investigate the redox couple of tris(1,10-phenanthroline)cobalt(II), Co(phen)32+, as a promising mediator for dye-sensitized solar cells and redox flow batteries. A pristine eC surface overlaid with KCl is prepared in vacuum, protected from contamination in air, and exposed to an ultrapure aqueous solution of Co(phen)32+ by the dissolution of the protective KCl layer. We employ SECM-based nanogap voltammetry to quantitatively demonstrate that Co(phen)32+ is adsorbed on the pristine eC surface to electrostatically self-inhibit outer-sphere ET of nonadsorbed Co(phen)33+ and Co(phen)32+. Strong electrostatic repulsion among Co(phen)32+ adsorbates is also demonstrated by SECM-based nanogap voltammetry and cyclic voltammetry. Quantitatively, self-inhibitory ET is characterized by a linear decrease in the standard rate constant of Co(phen)32+ oxidation with a higher surface concentration of Co(phen)32+ at the formal potential. This unique relationship is consistent not with the Frumkin model of double layer effects, but with the Amatore model of partially blocked electrodes as extended for self-inhibitory ET. Significantly, the complicated coupling of electron transfer and surface adsorption is resolved by combining nanoscale and macroscale voltammetric methods.
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Affiliation(s)
- Ran Chen
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
| | - Amin Morteza Najarian
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2R3 , Canada
| | - Niraja Kurapati
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
| | - Ryan J Balla
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
| | - Alexander Oleinick
- PASTEUR, Département de Chimie , École Normale Supérieure, PSL Université, Sorbonne Université , CNRS, 75005 Paris , France
| | - Irina Svir
- PASTEUR, Département de Chimie , École Normale Supérieure, PSL Université, Sorbonne Université , CNRS, 75005 Paris , France
| | - Christian Amatore
- PASTEUR, Département de Chimie , École Normale Supérieure, PSL Université, Sorbonne Université , CNRS, 75005 Paris , France.,State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen , 361005 , China
| | - Richard L McCreery
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2R3 , Canada
| | - Shigeru Amemiya
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
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Zhou Z, Yan X, Saha ML, Zhang M, Wang M, Li X, Stang PJ. Immobilizing Tetraphenylethylene into Fused Metallacycles: Shape Effects on Fluorescence Emission. J Am Chem Soc 2016; 138:13131-13134. [PMID: 27672700 DOI: 10.1021/jacs.6b07173] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Herein, we describe the selective formation of a discrete fused metallarhomboid and a triangle by the careful control of the shape and stoichiometry of the building blocks. A tetraphenylethylene (TPE)-based tetrapyridyl donor is exploited as the bridging component, and coordination immobilization of the TPE unit within the rigid metallacyclic frameworks efficiently suppresses its intramolecular rotational motions. As a result, the fused polygons are innately emissive in dilute solution, representing an alternative to aggregation-induced emission. Upon further molecular aggregation, these metallacycles display aggregation-induced enhanced emissions. Interestingly, the fused rhomboid 7 shows a weaker fluorescence in dilute solutions relative to that of the fused triangle 8, while a reversal of emission intensities was observed in the aggregated state. These markedly different fluorescence efficiencies are likely due to the differences in the shapes of the fused polygons. Thus, this work shows that the properties of supramolecular coordination complexes can be affected by subtle structural factors, which can be controlled easily and precisely at the molecular level.
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Affiliation(s)
- Zhixuan Zhou
- Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Xuzhou Yan
- Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Manik Lal Saha
- Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Mingming Zhang
- Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Ming Wang
- Department of Chemistry and Biochemistry and Materials Science, Engineering, and Commercialization Program, Texas State University , San Marcos, Texas 78666, United States
| | - Xiaopeng Li
- Department of Chemistry and Biochemistry and Materials Science, Engineering, and Commercialization Program, Texas State University , San Marcos, Texas 78666, United States
| | - Peter J Stang
- Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
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Shankar B, Sahu S, Deibel N, Schweinfurth D, Sarkar B, Elumalai P, Gupta D, Hussain F, Krishnamoorthy G, Sathiyendiran M. Luminescent Dirhenium(I)-Double-Heterostranded Helicate and Mesocate. Inorg Chem 2014; 53:922-30. [DOI: 10.1021/ic4023135] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - Saugata Sahu
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781 039, India
| | - Naina Deibel
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany
| | - David Schweinfurth
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany
- Institut für
Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, D-14195 Berlin, Germany
| | - Biprajit Sarkar
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany
- Institut für
Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, D-14195 Berlin, Germany
| | - Palani Elumalai
- Department
of Chemistry, University of Delhi, Delhi 110 007, India
| | - Deepak Gupta
- Department
of Chemistry, University of Delhi, Delhi 110 007, India
| | - Firasat Hussain
- Department
of Chemistry, University of Delhi, Delhi 110 007, India
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Samanta D, Mukherjee PS. PtII6 nanoscopic cages with an organometallic backbone as sensors for picric acid. Dalton Trans 2013; 42:16784-95. [DOI: 10.1039/c3dt52268g] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Kubota R, Tashiro S, Umeki T, Shionoya M. Non-covalent surface modification of metal-macrocycle framework with mono-substituted benzenes. Supramol Chem 2012. [DOI: 10.1080/10610278.2012.733394] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Ryou Kubota
- a Department of Chemistry , Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo , 113-0033 , Japan
| | - Shohei Tashiro
- a Department of Chemistry , Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo , 113-0033 , Japan
| | - Tsutomu Umeki
- a Department of Chemistry , Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo , 113-0033 , Japan
| | - Mitsuhiko Shionoya
- a Department of Chemistry , Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo , 113-0033 , Japan
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8
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Tan C, Rodríguez-López J, Parks JJ, Ritzert NL, Ralph DC, Abruña HD. Reactivity of monolayer chemical vapor deposited graphene imperfections studied using scanning electrochemical microscopy. ACS NANO 2012; 6:3070-3079. [PMID: 22424270 DOI: 10.1021/nn204746n] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Imperfections that disrupt the sp(2) conjugation of graphene can alter its electrical, chemical, and mechanical properties. Here we report on the examination of monolayer chemical vapor deposited graphene imperfections using scanning electrochemical microscopy in the feedback mode. It was found that the sites with a large concentration of defects are approximately 1 order of magnitude more reactive, compared to more pristine graphene surfaces, toward electrochemical reactions. Furthermore, we successfully passivated the activity of graphene defects by carefully controlling the electropolymerization conditions of o-phenylenediamine. With further electropolymerization, a thin film of the polymer was formed, and it was found to be insulating in nature toward heterogeneous electron transfer processes. The use of spatially resolved scanning electrochemical microscopy for detecting the presence and the "healing" of defects on graphene provides a strategy for in situ characterization and control of this attractive surface, enabling optimization of its properties for application in electronics, sensing, and electrocatalysis.
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Affiliation(s)
- Cen Tan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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9
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Tashiro S, Kubota R, Shionoya M. Metal–Macrocycle Framework (MMF): Supramolecular Nano-Channel Surfaces with Shape Sorting Capability. J Am Chem Soc 2012; 134:2461-4. [PMID: 22148728 DOI: 10.1021/ja209422m] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shohei Tashiro
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Chakrabarty R, Mukherjee PS, Stang PJ. Supramolecular coordination: self-assembly of finite two- and three-dimensional ensembles. Chem Rev 2011; 111:6810-918. [PMID: 21863792 PMCID: PMC3212633 DOI: 10.1021/cr200077m] [Citation(s) in RCA: 2261] [Impact Index Per Article: 173.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Rajesh Chakrabarty
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Partha Sarathi Mukherjee
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Peter J Stang
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
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Motiei L, Kaminker R, Sassi M, van der Boom ME. Molecule and Electron Transfer through Coordination-Based Molecular Assemblies. J Am Chem Soc 2011; 133:14264-6. [DOI: 10.1021/ja206179a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Leila Motiei
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Revital Kaminker
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Mauro Sassi
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Milko E. van der Boom
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
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Lefrou C, Cornut R. Analytical expressions for quantitative scanning electrochemical microscopy (SECM). Chemphyschem 2010; 11:547-56. [PMID: 20058287 DOI: 10.1002/cphc.200900600] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Scanning electrochemical microscopy (SECM), is a recent analytical technique in electrochemistry, which was developed in the 1990s and uses microelectrodes to probe various surfaces. Even with the well-known disc microelectrodes, the system geometry is not as simple as in regular electrochemistry. As a consequence even the simplest experiments, the so-called positive and negative feedback approach curves, cannot be described with exact analytical expressions. This review gathers all the analytical expressions available in the SECM literature in steady-state feedback experiments. Some of them are claimed as general expressions, other are presented as approximate. Their validity is discussed in the light of the current understanding and computer facilities.
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Affiliation(s)
- Christine Lefrou
- LEPMI, Laboratoire d'Electrochimie et Physicochimie des Matériaux et des Interfaces, UMR 5631 CNRS-Grenoble-INP-Université Joseph Fourier, 1130 rue de la piscine, BP 75, Domaine Universitaire, 38402 Saint Martin d'Hères Cedex, France.
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Matrab T, Hauquier F, Combellas C, Kanoufi F. Scanning Electron Microscopy Investigation of Molecular Transport and Reactivity within Polymer Brushes. Chemphyschem 2010; 11:670-82. [DOI: 10.1002/cphc.200900766] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Pust SE, Maier W, Wittstock G. Investigation of Localized Catalytic and Electrocatalytic Processes and Corrosion Reactions with Scanning Electrochemical Microscopy (SECM). ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zpch.2008.5426] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
AbstractScanning electrochemical microscopy (SECM) has developed into a very versatile tool for the investigation of solid-liquid, liquid-liquid and liquid-gas interfaces. The arrangement of an ultramicroelectrode (UME) in close proximity to the interface under study allows the application of a large variety of different experimental schemes. The most important have been named feedback mode, generation-collection mode, redox competition mode and direct mode. Quantitative descriptions are available for the UME signal, depending on different sample properties and experimental variables. Therefore, SECM has been established as an indispensible tool in many areas of fundamental electrochemical research. Currently, it also spreads as an important new method to solve more applied problems, in which inhomogeneous current distributions are typically observed on different length scales. Prominent examples include devices for electrochemical energy conversion such as fuel cells and batteries as well as localized corrosion phenomena. However, the direct local investigation of such systems is often impossible. Instead, suitable reaction schemes, sample environments, model samples and even new operation modes have to be introduced in order to obtain results that are relevant to the practical application. This review outlines and compares the theoretical basis of the different SECM working modes and reviews the application in the area of electrochemical energy conversion and localized corrosion with a special emphasis on the problems encountered when working with practical samples.
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Li SS, Northrop BH, Yuan QH, Wan LJ, Stang PJ. Surface confined metallosupramolecular architectures: formation and scanning tunneling microscopy characterization. Acc Chem Res 2009; 42:249-59. [PMID: 19072706 DOI: 10.1021/ar800117j] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metallosupramolecular compounds have attracted a great deal of attention over the past two decades largely because of their unique, highly complex structural characteristics and their potential electronic, magnetic, optical, and catalytic properties. These molecules can be prepared with relative ease using coordination-driven self-assembly techniques. In particular, the use of electron-poor square-planar Pt(II) transition metals in conjunction with rigid, electron-rich pyridyl donors has enabled the spontaneous self-assembly of a rich library of 2D metallacyclic and 3D metallacage assemblies via the directional-bonding approach. With this progress in the preparation and characterization of metallosupramolecules, researchers have now turned their attention toward fully exploring and developing their materials properties. Assembling metallosupramolecular compounds on solid supports represents a vitally important step toward developing their materials properties. Surfaces provide a means of uniformly aligning and orienting these highly symmetric metallacycles and metallacages. This uniformity increases the level of coherence between molecules above that which can be achieved in the solution phase and provides a way to integrate adsorbed layers, or adlayers, into a solid-state materials setting. The dynamic nature of kinetically labile Pt(II)-N coordination bonds requires us to adjust deposition and imaging conditions to retain the assemblies' stability. Toward these aims, we have used scanning tunneling microscopy (STM) to image these adlayers and to understand the factors that govern surface self-assembly and the interactions that influence their structure and stability. This Account describes our efforts to deposit 2D rectangular and square metallacycles and 3D trigonal bipyramidal and chiral trigonal prism metallacages on highly oriented pyrolytic graphite (HOPG) and Au(111) substrates to give intact assemblies and ordered adlayers. We have investigated the effects of varying the size, symmetry, and dimensionality of supramolecular adsorbates, the choice of substrate, the use of a molecular template, and the effects of chirality. Our systematic investigations provide insights into the various adsorbate-adsorbate and substrate-adsorbate interactions that largely determine the architecture of each assembly and affect their performance in a materials setting. Rational control over adlayer formation and structure will greatly enhance the potential of these supramolecules to be used in a variety of applications such as host-guest sensing/diagnostic systems, molecular electronic devices, and heterogeneous stereoselective synthesis and catalysis.
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Affiliation(s)
- Shan-Shan Li
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Brian H. Northrop
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112
| | - Qun-Hui Yuan
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Li-Jun Wan
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Peter J. Stang
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112
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Abstract
Coordination-driven self-assembly via the directional-bonding approach utilizes rigid transition metal acceptors and electron-rich donors to allow for complex, nanoscale 2D polygons and 3D polyhedra to be prepared under mild conditions and in high yields. To ensure proper rigidity and directionality, many acceptor and donor precursors contain largely carbon-rich aromatic and/or acetylenic moieties. This article introduces self-assembly as an alternative means of synthesizing carbon-rich materials and discusses the development, design, synthesis, and applications of carbon-rich supramolecular metallacycles and metallacages as well as the self-assembly of new diastereomeric carbon-rich supramolecular triangles.
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17
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Studying permeable films with scanning electrochemical microscopy (SECM): Quantitative determination of permeability parameter. J Electroanal Chem (Lausanne) 2008. [DOI: 10.1016/j.jelechem.2008.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Wittstock G, Burchardt M, Pust SE, Shen Y, Zhao C. Scanning electrochemical microscopy for direct imaging of reaction rates. Angew Chem Int Ed Engl 2007; 46:1584-617. [PMID: 17285666 DOI: 10.1002/anie.200602750] [Citation(s) in RCA: 313] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Not only in electrochemistry but also in biology and in membrane transport, localized processes at solid-liquid or liquid-liquid interfaces play an important role at defect sites, pores, or individual cells, but are difficult to characterize by integral investigation. Scanning electrochemical microscopy is suitable for such investigations. After two decades of development, this method is based on a solid theoretical foundation and a large number of demonstrated applications. It offers the possibility of directly imaging heterogeneous reaction rates and locally modifying substrates by electrochemically generated reagents. The applications range from classical electrochemical problems, such as the investigation of localized corrosion and electrocatalytic reactions in fuel cells, sensor surfaces, biochips, and microstructured analysis systems, to mass transport through synthetic membranes, skin and tissue, as well as intercellular communication processes. Moreover, processes can be studied that occur at liquid surfaces and liquid-liquid interfaces.
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Affiliation(s)
- Gunther Wittstock
- Carl von Ossietzky Universität Oldenburg, Institut für Reine und Angewandte Chemie und Institut für Chemie und Biologie des Meeres, 26111 Oldenburg, Germany.
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Wittstock G, Burchardt M, Pust S, Shen Y, Zhao C. Elektrochemische Rastermikroskopie zur direkten Abbildung von Reaktionsgeschwindigkeiten. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200602750] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Massari AM, Gurney RW, Schwartz CP, Nguyen ST, Hupp JT. Walljet electrochemistry: quantifying molecular transport through metallopolymeric and zirconium phosphonate assembled porphyrin square thin films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:4422-9. [PMID: 15969148 DOI: 10.1021/la049900+] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
By employing redox-active probes, condensed-phase molecular transport through nanoporous thin films can often be measured electrochemically. Certain kinds of electrode materials (e.g. conductive glass) are difficult to fabricate as rotatable disks or as ultramicroelectrodes-the configurations most often used for electrochemical permeation measurements. These limitations point to the need for a more materials-general measurement method. Herein, we report the application of walljet electrochemistry to the study of molecular transport through model metallopolymeric films on indium tin oxide electrodes. A quantitative expression is presented that describes the transport-limited current at the walljet electrode in terms of mass transport through solution and permeation through the film phase. A comparison of the film permeabilities for a series of redox probes measured using the walljet electrode and a rotating disk electrode establishes the accuracy of the walljet method, while also demonstrating similar precision for the two methods. We apply this technique to a system consisting of zirconium phosphonate assembled films of a porphyrinic molecular square. Transport through films comprising three or more layers is free from significant contributions from pinhole defects. Surprisingly, transport through films of this kind is 2-3 orders of magnitude slower than through films constructed via interfacial polymerization of nearly identical supramolecular square building blocks (Keefe; et al. Adv. Mater. 2003, 15, 1936). The zirconium phosphate assembled films show good size exclusion behavior. The details of the observed dependence of permeation rates on probe molecule size can be rationalized with a model that assumes that the walls of the squares are slightly tilted from a strictly vertical geometry, consistent with atomic force microscopy measurements, and assumes that the individual wall geometries are locked by rigid interlayer linkages.
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Affiliation(s)
- Aaron M Massari
- Department of Chemistry and the Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
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Crystal engineering of Pd(II) compounds with 2-amino-5-mercapto-1,3,4-thiadiazolate or 6-amino-2-mercaptobenzothiazolate. INORG CHEM COMMUN 2004. [DOI: 10.1016/j.inoche.2003.10.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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