Electrografting of diazonium salts: A kinetics study

Bouden, Sarra; Pinson, Jean; Vautrin-Ul, Christine

doi:10.1016/j.elecom.2017.06.007

Cited by 33 publications

(38 citation statements)

References 32 publications

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“…The number of layers can then be calculated by taking the ratio between surface concentration obtained from CV and the theoretical value [ 34 ]. The theoretical surface concentration of a close-packed layer of CP was estimated from the structure of benzoic acid in which its geometry was optimized using Avogadro software.…”

Section: Resultsmentioning

confidence: 99%

Electrografting of 4-Carboxybenzenediazonium on Glassy Carbon Electrode: The Effect of Concentration on the Formation of Mono and Multilayers

et al. 2020

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Grafting of electrodes with diazonium salts using cyclic voltammetry (CV) is a well-established procedure for surface modification. However, little is known about the effect of the concentration of the diazonium salt on the number of layers grafted on the electrode surface. In this work, the impact of concentration on the grafting of 4-carboxybenzenediazonium (4-CBD) onto a glassy carbon electrode (GCE) is elucidated. The number of layers grafted on the GCE was linearly dependent on the concentration of 4-CBD and varied between 0.9 and 4.3 when the concentration was varied between 0.050 and 0.30 mmol/L at 0.10 V.s−1. Characterization of modified glassy carbon surface with X-ray photoelectron spectroscopy (XPS) confirmed the grafting of carboxyphenyl layer on the surface. Grafting with 0.15 mmol/L 4-CBD (1 CV cycle) did not form a detectable amount of carboxyphenyl (CP) moieties at the surface, while a single scan with higher concentration (2.5 mmol/L) or multiple scans (22 cycles) gave detectable signals, indicating formation of multilayers. We also demonstrate the possibility of removing the thin layer grafted on a glassy carbon electrode by applying high oxidation potential +1.40 V.

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Section: Resultsmentioning

confidence: 99%

Electrografting of 4-Carboxybenzenediazonium on Glassy Carbon Electrode: The Effect of Concentration on the Formation of Mono and Multilayers

et al. 2020

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“…10,[32][33][34] The relative reactivities of grafting on gold electrodes by aryl radicals bearing a substituent of different electronic properties at the 4-position has been evaluated recently by measuring initial rates. 35 Plotting initial reaction rates with respect to the Hammett substituent  constants showed a reasonable linear trend, though it turned out difficult to compare grafting densities owing to the competitive multi-layer growth. Such reactivity comparison of aryl radicals having different electronic character has yet to be reported for graphitic surfaces.…”

Section: Introductionmentioning

confidence: 99%

Steric and Electronic Effects of Electrochemically Generated Aryl Radicals on Grafting of the Graphite Surface

et al. 2019

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Surface grafting of aryl radicals generated by electrochemical reduction of aryldiazonium salts has been extensively studied on various surfaces. However, there exits two unclear aspects; the first one is the generality of the blocking ability of simple functional groups towards multi-layer growth, and the second one is the electronic impact of substituent groups of aryl radicals on grafting efficiency. To address these aspects, we have studied the electrochemical functionalization of graphite using aryldiazonium salts having electron-donating or -withdrawing groups at the 3,4,5-positions. AFM investigation of the functionalized surfaces revealed the formation of monolayers for all aryldiazonium salts, and thus nitro, carboxy, ester, methyl and methoxy groups at the 3,4,5-positions of the benzene ring suppress polyaryl growth. The degree of grafting estimated by STM imaging and Raman spectroscopy of the functionalized surfaces depends on the electronic state of the aryl radicals, in which the radicals with electron-donating groups show a high degree of functionalization, while those with electron-withdrawing groups exhibit a low degree of functionalization. We discuss several possibilities that affect grafting density. Though there are several factors, we hypothesize that one factor to explain the observed reactivity trend is the electronic property of the aryl radicals, namely the relative position of the singly-occupied molecular orbital (SOMO) energy levels of the aryl radicals with respect to the graphite Fermi energy level. ASSOCIATED CONTENT Supporting InformationExperimental details, synthesis of 5a, washing procedure of functionalized HOPG by 6a, model of the bilayer formed by 6a, details of formation and dediazoniation for aryldiazonium salts, and results of post functionalization. This material is available free of charge via the Internet at http://pubs.acs.org.

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“…QCM measurement was used to probe the thickness of the electrodeposited aryl organic layer on an Au electrode, and suggested that the large size of the substituent and its steric hindrance typically led to the formation of thin layers [112]. A recent study related to the kinetics of electrografting on gold surfaces also suggested that the presence of an electron-attracting group increases the rate of reaction of the aryl radical on the gold surface [113], whereas the presence of an electron-donating group slows down the grafting process, thereby offering control over the possibility to form monolayers. It should be noted that a mixed layer of aromatic diazonium salt and thiol can be advantageously used, as demonstrated in the case of LAC on gold electrodes.…”

Section: Electrode Functionalizationmentioning

confidence: 99%

Controlling Redox Enzyme Orientation at Planar Electrodes

et al. 2018

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Abstract:Redox enzymes, which catalyze reactions involving electron transfers in living organisms, are very promising components of biotechnological devices, and can be envisioned for sensing applications as well as for energy conversion. In this context, one of the most significant challenges is to achieve efficient direct electron transfer by tunneling between enzymes and conductive surfaces. Based on various examples of bioelectrochemical studies described in the recent literature, this review discusses the issue of enzyme immobilization at planar electrode interfaces. The fundamental importance of controlling enzyme orientation, how to obtain such orientation, and how it can be verified experimentally or by modeling are the three main directions explored. Since redox enzymes are sizable proteins with anisotropic properties, achieving their functional immobilization requires a specific and controlled orientation on the electrode surface. All the factors influenced by this orientation are described, ranging from electronic conductivity to efficiency of substrate supply. The specificities of the enzymatic molecule, surface properties, and dipole moment, which in turn influence the orientation, are introduced. Various ways of ensuring functional immobilization through tuning of both the enzyme and the electrode surface are then described. Finally, the review deals with analytical techniques that have enabled characterization and quantification of successful achievement of the desired orientation. The rich contributions of electrochemistry, spectroscopy (especially infrared spectroscopy), modeling, and microscopy are featured, along with their limitations.

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Electrografting of diazonium salts: A kinetics study

Cited by 33 publications

References 32 publications

Electrografting of 4-Carboxybenzenediazonium on Glassy Carbon Electrode: The Effect of Concentration on the Formation of Mono and Multilayers

Electrografting of 4-Carboxybenzenediazonium on Glassy Carbon Electrode: The Effect of Concentration on the Formation of Mono and Multilayers

Steric and Electronic Effects of Electrochemically Generated Aryl Radicals on Grafting of the Graphite Surface

Controlling Redox Enzyme Orientation at Planar Electrodes

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