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Zhang L, Li N, Chen Z, Li X, Fan A, Shao H. Investigating the substitution of intermolecular hydrogen bonds on the surface of self-assembled monolayer by scanning electrochemical microscopy. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Li R, Ji W, Chen L, Lv H, Cheng J, Zhao B. Vibrational spectroscopy and density functional theory study of 4-mercaptophenol. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 122:698-703. [PMID: 24361735 DOI: 10.1016/j.saa.2013.11.109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 11/08/2013] [Accepted: 11/28/2013] [Indexed: 05/26/2023]
Abstract
In this paper, 4-mercaptophenol (4-MPH) was designed as a model molecule for theoretical and experimental studies of the molecule structure. Density functional theory (DFT) calculations have been performed to predict the IR and Raman spectra for the molecule. In addition, Fourier transform infrared (FTIR) and Raman spectra of the compound have been obtained experimentally. All FTIR and Raman bands of the compound obtained experimentally were assigned based on the modeling results obtained at the B3LYP/6-311+G(**) level. Our calculated vibrational frequencies are in good agreement with the experimental vales. The molecular electrostatic potential surface calculation was performed and the result suggested that the 4-MPH has two hydrogen bond donors and three hydrogen bond acceptors. HOMO-LUMO gap was also obtained theoretically at B3LYP/6-311+G** level.
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Affiliation(s)
- Ran Li
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, China
| | - Wei Ji
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, China
| | - Lei Chen
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, China
| | - Haiming Lv
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, China; Center for Composite Material, Harbin Institute of Technology, Harbin, China
| | - Jianbo Cheng
- The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, China
| | - Bing Zhao
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, China.
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Preparation and characterization of DNA films using oleylamine modified Au surfaces. J Colloid Interface Sci 2011; 358:626-34. [DOI: 10.1016/j.jcis.2011.03.039] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/10/2011] [Accepted: 03/11/2011] [Indexed: 11/22/2022]
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Abstract
AbstractThe field of self-assembled monolayers (SAMs) of organic compounds on different substrates is of importance because it provides a suitable and efficient method of surface modification. The formation of robust, stable monolayers from carboxylic acids on two and three dimensional surfaces of different substrates have been reported. Carboxylic acids are promising class of organic compounds for monolayer formations where traditional alkanethiols or alkoxysilanes show limitations.
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Waldeck DH, Khoshtariya DE. Fundamental Studies of Long- and Short-Range Electron Exchange Mechanisms between Electrodes and Proteins. MODERN ASPECTS OF ELECTROCHEMISTRY 2011. [DOI: 10.1007/978-1-4614-0347-0_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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6
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Salamifar SE, Mehrgardi MA, Kazemi SH, Mousavi MF. Cyclic voltammetry and scanning electrochemical microscopy studies of methylene blue immobilized on the self-assembled monolayer of n-dodecanethiol. Electrochim Acta 2010. [DOI: 10.1016/j.electacta.2010.08.068] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Eckermann AL, Feld DJ, Shaw JA, Meade TJ. Electrochemistry of redox-active self-assembled monolayers. Coord Chem Rev 2010; 254:1769-1802. [PMID: 20563297 PMCID: PMC2885823 DOI: 10.1016/j.ccr.2009.12.023] [Citation(s) in RCA: 357] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Redox-active self-assembled monolayers (SAMs) provide an excellent platform for investigating electron transfer kinetics. Using a well-defined bridge, a redox center can be positioned at a fixed distance from the electrode and electron transfer kinetics probed using a variety of electrochemical techniques. Cyclic voltammetry, AC voltammetry, electrochemical impedance spectroscopy, and chronoamperometry are most commonly used to determine the rate of electron transfer of redox-activated SAMs. A variety of redox species have been attached to SAMs, and include transition metal complexes (e.g., ferrocene, ruthenium pentaammine, osmium bisbipyridine, metal clusters) and organic molecules (e.g., galvinol, C(60)). SAMs offer an ideal environment to study the outer-sphere interactions of redox species. The composition and integrity of the monolayer and the electrode material influence the electron transfer kinetics and can be investigated using electrochemical methods. Theoretical models have been developed for investigating SAM structure. This review discusses methods and monolayer compositions for electrochemical measurements of redox-active SAMs.
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Calvente JJ, López-Pérez G, Jurado JM, Andreu R, Molero M, Roldán E. Reorientation of thiols during 2D self-assembly: interplay between steric and energetic factors. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:2914-2923. [PMID: 19764782 DOI: 10.1021/la902981n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Reorientation of thiols during their 2D self-assembly is well established; however, little is known about its energetics and the factors that control its onset. We have developed a new strategy to determine the critical reorientational surface concentration (crsc) of thiols at the substrate/solution interface, which makes use of a cathodic stripping protocol. Its application to distinct homologous series of alkylthiols shows that the magnitude of the crsc and its variation with the molecular size is strongly dependent on the nature of the terminal group. Methyl-terminated alkylthiols reorient close to the saturation coverage of the lying-down phase, thus following their molecular size trend; whereas reorientation of alkylthiols bearing a negatively charged end group starts well below the monolayer coverage of the lying-down phase, with its onset being almost independent of the molecular size. Hydroxy-terminated alkylthiols show an intermediate behavior. A theoretical approach is developed to determine the reorientation equilibrium constant from the crsc value. The standard free energy of reorientation has been found to vary linearly with the alkyl chain length, and to increase upon replacing the terminal methyl group by a negatively charged one. A quantitative correlation between the reorientation equilibrium constant and the hydrophobicity of the molecule has been established. Overall, these findings have allowed us to disentangle the role of steric and energetic factors in the onset of the reorientation process of alkylthiols, demonstrating that their interplay can be finely tuned by varying either the alkyl chain length or the nature of the terminal group.
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Affiliation(s)
- Juan José Calvente
- Departamento de Química Física, Facultad de Química, Universidad de Sevilla, 41012, Sevilla, Spain.
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Qu X, Bond A, Martin L. Interference from Trace Copper in Electrochemical Investigations Employing Carboxylic Acid Terminated Thiol Modified Gold Electrodes. ELECTROANAL 2009. [DOI: 10.1002/elan.200804462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Menshykau D, Compton RG. Electrodes modified with electroinactive layers: distinguishing through-film transport from pinhole (pore) diffusion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:2519-2529. [PMID: 19199745 DOI: 10.1021/la803488t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Electrodes modified with layers, for example, of polymers or self-assembled monolayers, are of great importance from both the fundamental and applied points of view. Two different models of electrodes covered with electroinactive layers can be proposed. First, the electrode is covered with a uniform layer into which the electroactive species dissolves and then diffuses through, or second, the layer contains pinholes that are exclusively responsible for diffusional transport to the electrode. Both models are simulated and then compared to identify conditions under which they can be distinguished. The models are studied for a broad range of parameters reflecting experimentally viable values. Different types of cyclic voltammograms can be observed in the studied models corresponding to classical Randles-Sevcik, thin layer, and steady-state behaviors. We show that the models can be distinguished experimentally through recording cyclic voltammograms over a sufficiently broad range of voltage scan rates.
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Affiliation(s)
- Denis Menshykau
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, United Kingdom OX1 3QZ
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Tran E, Cohen AE, Murray RW, Rampi MA, Whitesides GM. Redox Site-Mediated Charge Transport in a Hg−SAM//Ru(NH3)63+/2+//SAM−Hg Junction with a Dynamic Interelectrode Separation: Compatibility with Redox Cycling and Electron Hopping Mechanisms. J Am Chem Soc 2009; 131:2141-50. [DOI: 10.1021/ja804075y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elizabeth Tran
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge,Massachusetts 02138; Dipartimento di Chimica, Università di Ferrara, 44100 Ferrara, Italy; and Kenan Laboratories of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27510
| | - Adam E. Cohen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge,Massachusetts 02138; Dipartimento di Chimica, Università di Ferrara, 44100 Ferrara, Italy; and Kenan Laboratories of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27510
| | - Royce W. Murray
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge,Massachusetts 02138; Dipartimento di Chimica, Università di Ferrara, 44100 Ferrara, Italy; and Kenan Laboratories of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27510
| | - Maria A. Rampi
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge,Massachusetts 02138; Dipartimento di Chimica, Università di Ferrara, 44100 Ferrara, Italy; and Kenan Laboratories of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27510
| | - George M. Whitesides
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge,Massachusetts 02138; Dipartimento di Chimica, Università di Ferrara, 44100 Ferrara, Italy; and Kenan Laboratories of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27510
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Dai J, Li Z, Jin J, Shi Y, Cheng J, Kong J, Bi S. Some thoughts on the existence of ion and water channels in highly dense and well-ordered CH3-terminated alkanethiol self-assembled monolayers on gold. Biosens Bioelectron 2009; 24:1074-82. [DOI: 10.1016/j.bios.2008.08.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 07/30/2008] [Accepted: 08/15/2008] [Indexed: 11/27/2022]
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Voltammetric response of a glassy carbon electrode modified by a Langmuir–Blodgett film of a thiomacrocyclic compound. J Electroanal Chem (Lausanne) 2008. [DOI: 10.1016/j.jelechem.2007.11.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Björefors F, Petoral RM, Uvdal K. Electrochemical Impedance Spectroscopy for Investigations on Ion Permeation in ω-Functionalized Self-Assembled Monolayers. Anal Chem 2007; 79:8391-8. [PMID: 17902699 DOI: 10.1021/ac071399d] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electrochemical impedance spectroscopy was employed to explore the possibility of relating the permeation of electrolyte ions in omega-functionalized self-assembled monolayers to structural or polarity changes induced by interaction with metal ions. The monolayers were based on alkanethiols modified with a phosphorylated tyrosine analogue, which from previous work are known to drastically change their organization on gold surfaces upon interaction with aluminum and magnesium ions. The ion permeation was evaluated by using relatively low excitation frequencies, 1000 to 2 Hz, and quantified by an extra resistive component in the equivalent circuit (RSAM). The extent of ion permeation influenced by the dc potential, the electrolyte concentration, the functional group, and the thiol length were also investigated. It was, for example, found that RSAM decreased approximately 20% when the thiol organization collapsed and that RSAM increased approximately 4-5 times when the electrolyte concentration was decreased by 1 order of magnitude. Interesting observations were also made regarding the potential dependence of RSAM and the double layer capacitance. The evaluation of the ion permeation can be used to indirectly detect whether the organization of a SAM is influenced by, for example, electric fields or chemical and biological interactions. This analysis can be performed without addition of redox species, but is on the other hand complicated by the fact that other factors also influence the presence of ions within the monolayer. In addition, a second parallel RC process was obtained in some of the impedance spectra when using even lower frequencies, and its resistive component revealed different results compared to RSAM. Such data may be useful for the understanding of complex double layer phenomena at modified electrodes.
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Affiliation(s)
- Fredrik Björefors
- Division of Sensor Science and Molecular Physics, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden.
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Laaksonen T, Pelliniemi O, Quinn BM. Ion permeability of SAMs on nanoparticle surfaces. J Am Chem Soc 2007; 128:14341-6. [PMID: 17076507 DOI: 10.1021/ja064701t] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This article reports on the ion permeability of self-assembled monolayers (SAMs) formed on the surface of charged alkanethiol-protected gold nanoparticles, so-called monolayer-protected clusters (MPCs). The capacitance and thus the charging energy required to add/remove an electron from the metal core are extremely sensitive to ions entering the monolayer, and the extent of ion penetration can be tuned by the charge and size of the ions and the permittivity of the solvent. Experimentally, this effect is comparable to ion association with conventional redox molecules, indicating that MPCs despite their large size and the fundamentally differing nature of the electron transfer process can be treated analogously to redox molecules.
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Affiliation(s)
- Timo Laaksonen
- Laboratory of Physical Chemistry and Electrochemistry, Helsinki University of Technology, P.O. Box 6100, FIN-02015 HUT, Finland
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Ramírez P, Andreu R, Cuesta A, Calzado CJ, Calvente JJ. Determination of the Potential of Zero Charge of Au(111) Modified with Thiol Monolayers. Anal Chem 2007; 79:6473-9. [PMID: 17676927 DOI: 10.1021/ac071341z] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A new method is proposed for the determination of the potential of zero charge of gold electrodes modified with thiol monolayers. It makes use of the immersion technique, in combination with a vapor deposition protocol to build the thiol monolayers. As compared to previous methods, the present approach provides more accurate results, particularly in the case of long-chain alkanethiol monolayers, and it is applicable to any monolayer irrespective of its degree of hydrophilicity. Results are presented for a series of 12 alkanethiol monolayers and for 11-mercaptoundecanol and 11-mercaptoundecanoic acid monolayers. Good agreement is found between the variation of the potential of zero charge along the alkanethiol series with the corresponding change of the surface work function. The potential of zero charge of the 11-mercaptoundecanoic acid monolayer is shown to depend on the extent of dissociation of the acid, thus opening the possibility of applying this type of measurements to the study of surface ionization processes.
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Affiliation(s)
- Pablo Ramírez
- Departamento de Química Física, Universidad de Sevilla, 41012, Sevilla, Spain
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Lee JRI, Willey TM, Nilsson J, Terminello LJ, De Yoreo JJ, van Buuren T. Effect of ring substitution position on the structural conformation of mercaptobenzoic acid self-assembled monolayers on Au(111). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:11134-41. [PMID: 17154594 DOI: 10.1021/la0611256] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, photoemission spectroscopy (PES), and contact angle measurements have been used to examine the structure and bonding of self-assembled monolayers (SAMs) prepared on Au(111) from the positional isomers of mercaptobenzoic acid (MBA). The isomer of MBA and solvent chosen in SAM preparation has considerable bearing upon film morphology. Carbon K-edge NEXAFS measurements indicate that the monomers of 2-, 3-, and 4-MBA have well-defined orientations within their respective SAMs. Monomers of 3- and 4-MBA assume an upright orientation on the Au substrates in monolayers prepared using an acetic acid in ethanol solvent. The aryl ring and carboxyl group of these molecules are tilted from the surface normal by a colatitudal angle of approximately 30 degrees . Preparation of 4-MBA SAMs using pure ethanol solvent, a more traditional means of synthesis, had no appreciable effect upon the monomer orientation. Nonetheless, S(2p) PES measurements illustrate that it results in extensive bilayer formation via carboxyl group hydrogen-bonding between 4-MBA monomers. In 2-MBA monolayers prepared using acetic acid/ethanol solvent, the monomers adopt a more prostrate orientation on the Au substrates, in which the aryl ring and carboxyl group of the molecules are tilted approximately 50 degrees from the surface normal. This configuration is consistent with an interaction between both the mercaptan sulfur and carboxyl group of 2-MBA with the underlying substrate. S(2p) and C(1s) PES experiments provide supporting evidence for a bidentate interaction between 2-MBA and Au(111).
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Affiliation(s)
- Jonathan R I Lee
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
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Andreu R, Ferapontova EE, Gorton L, Calvente JJ. Direct Electron Transfer Kinetics in Horseradish Peroxidase Electrocatalysis. J Phys Chem B 2006; 111:469-77. [PMID: 17214499 DOI: 10.1021/jp064277i] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The study of direct electron transfer between enzymes and electrodes is frequently hampered by the small fraction of adsorbed proteins that remains electrochemically active. Here, we outline a strategy to overcome this limitation, which is based on a hierarchical analysis of steady-state electrocatalytic currents and the adoption of the "binary activity" hypothesis. The procedure is illustrated by studying the electrocatalytic response of horseradish peroxidase (HRP) adsorbed on graphite electrodes as a function of substrate (hydrogen peroxide) concentration, electrode potential, and solution pH. Individual contributions of the rates of substrate/enzyme reaction and of the electrode/enzyme electron exchange to the observed catalytic currents were disentangled by taking advantage of their distinct dependence on substrate concentration and electrode potential. In the absence of nonturnover currents, adoption of the "binary activity" hypothesis provided values of the standard electron-transfer rate constant for reduction of HRP Compound II that are similar to those reported previously for reduction of cytochrome c peroxidase Compound II. The variation of the catalytic currents with applied potential was analyzed in terms of the non-adiabatic Marcus-DOS electron transfer theory. The availability of a broad potential window, where catalytic currents could be recorded, facilitates an accurate determination of both the reorganization energy and the maximum electron-transfer rate for HRP Compound II reduction. The variation of these two kinetic parameters with solution pH provides some indication of the nature and location of the acid/base groups that control the electronic exchange between enzyme and electrode.
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Affiliation(s)
- Rafael Andreu
- Departamento de Química Física, Universidad de Sevilla, 41012-Sevilla, Spain
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Electrochemical and EQCM investigation of a selenium derivatized carotenoid in the self-assembled state at a gold electrode. J Electroanal Chem (Lausanne) 2006. [DOI: 10.1016/j.jelechem.2006.01.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Cohen-Atiya M, Nelson A, Mandler D. Characterization of n-alkanethiol self-assembled monolayers on mercury by impedance spectroscopy and potentiometric measurements. J Electroanal Chem (Lausanne) 2006. [DOI: 10.1016/j.jelechem.2006.04.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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