Diazonium salt derivatives of osmium bipyridine complexes: Electrochemical grafting and characterisation of modified surfaces

David J. Garrett; Peter Jenkins; Matthew I.J. Polson; Dónal Leech; Keith H.R. Baronian; Alison J. Downard

doi:10.1016/j.electacta.2010.11.070

Diazonium salt derivatives of osmium bipyridine complexes: Electrochemical grafting and characterisation of modified surfaces

David J. Garrett, Peter Jenkins, Matthew I.J. Polson, Dónal Leech, Keith H.R. Baronian, Alison J. Downard

Cellular & Molecular Medicine

Research output: Contribution to a Journal (Peer & Non Peer) › Article › peer-review

21 Citations (Scopus)

Abstract

Osmium bipyridine complexes were directly grafted to carbon electrodes through electroreduction of the diazonium salts [Os(bpy-ph-N₂ ⁺)₃](PF₆)₅ (1) and [Os(bpy-ph-N ₂⁺)₂Cl₂](PF₆) ₂ (2). Growth of the films was not self-limiting as is usually found for grafting from diazonium salts. It appears that electron hopping through the bipyridine ligands of the immobilised complexes enables film growth to continue at a constant rate during grafting by potential cycling. The surface concentrations of deposited films were measured electrochemically and the film thicknesses were measured by depth-profiling using the atomic force microscope. Films up to 42 nm thick were prepared with no evidence for slowing of film growth. The grafted films exhibited high stability when repetitively cycled through the Os^2+/3+ couple and electron transfer rate constants of 11.4 s^-1 and 35.4 s^-1 were measured in ACN and PBS, respectively, for the Os^2+/3+ couple of the film grafted from 1.

Original language	English
Pages (from-to)	2213-2220
Number of pages	8
Journal	Electrochimica Acta
Volume	56
Issue number	5
DOIs	https://doi.org/10.1016/j.electacta.2010.11.070
Publication status	Published - 1 Feb 2011

Keywords

AFM depth profiling
Diazonium salt
Electrografting
Electron transfer rate constant
Osmium complex

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10.1016/j.electacta.2010.11.070

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title = "Diazonium salt derivatives of osmium bipyridine complexes: Electrochemical grafting and characterisation of modified surfaces",

abstract = "Osmium bipyridine complexes were directly grafted to carbon electrodes through electroreduction of the diazonium salts [Os(bpy-ph-N2 +)3](PF6)5 (1) and [Os(bpy-ph-N 2+)2Cl2](PF6) 2 (2). Growth of the films was not self-limiting as is usually found for grafting from diazonium salts. It appears that electron hopping through the bipyridine ligands of the immobilised complexes enables film growth to continue at a constant rate during grafting by potential cycling. The surface concentrations of deposited films were measured electrochemically and the film thicknesses were measured by depth-profiling using the atomic force microscope. Films up to 42 nm thick were prepared with no evidence for slowing of film growth. The grafted films exhibited high stability when repetitively cycled through the Os2+/3+ couple and electron transfer rate constants of 11.4 s-1 and 35.4 s-1 were measured in ACN and PBS, respectively, for the Os2+/3+ couple of the film grafted from 1.",

keywords = "AFM depth profiling, Diazonium salt, Electrografting, Electron transfer rate constant, Osmium complex",

author = "Garrett, \{David J.\} and Peter Jenkins and Polson, \{Matthew I.J.\} and D{\'o}nal Leech and Baronian, \{Keith H.R.\} and Downard, \{Alison J.\}",

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doi = "10.1016/j.electacta.2010.11.070",

language = "English",

volume = "56",

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T2 - Electrochemical grafting and characterisation of modified surfaces

AU - Garrett, David J.

AU - Jenkins, Peter

AU - Polson, Matthew I.J.

AU - Leech, Dónal

AU - Baronian, Keith H.R.

AU - Downard, Alison J.

PY - 2011/2/1

Y1 - 2011/2/1

N2 - Osmium bipyridine complexes were directly grafted to carbon electrodes through electroreduction of the diazonium salts [Os(bpy-ph-N2 +)3](PF6)5 (1) and [Os(bpy-ph-N 2+)2Cl2](PF6) 2 (2). Growth of the films was not self-limiting as is usually found for grafting from diazonium salts. It appears that electron hopping through the bipyridine ligands of the immobilised complexes enables film growth to continue at a constant rate during grafting by potential cycling. The surface concentrations of deposited films were measured electrochemically and the film thicknesses were measured by depth-profiling using the atomic force microscope. Films up to 42 nm thick were prepared with no evidence for slowing of film growth. The grafted films exhibited high stability when repetitively cycled through the Os2+/3+ couple and electron transfer rate constants of 11.4 s-1 and 35.4 s-1 were measured in ACN and PBS, respectively, for the Os2+/3+ couple of the film grafted from 1.

AB - Osmium bipyridine complexes were directly grafted to carbon electrodes through electroreduction of the diazonium salts [Os(bpy-ph-N2 +)3](PF6)5 (1) and [Os(bpy-ph-N 2+)2Cl2](PF6) 2 (2). Growth of the films was not self-limiting as is usually found for grafting from diazonium salts. It appears that electron hopping through the bipyridine ligands of the immobilised complexes enables film growth to continue at a constant rate during grafting by potential cycling. The surface concentrations of deposited films were measured electrochemically and the film thicknesses were measured by depth-profiling using the atomic force microscope. Films up to 42 nm thick were prepared with no evidence for slowing of film growth. The grafted films exhibited high stability when repetitively cycled through the Os2+/3+ couple and electron transfer rate constants of 11.4 s-1 and 35.4 s-1 were measured in ACN and PBS, respectively, for the Os2+/3+ couple of the film grafted from 1.

KW - AFM depth profiling

KW - Diazonium salt

KW - Electrografting

KW - Electron transfer rate constant

KW - Osmium complex

UR - https://www.scopus.com/pages/publications/79551569207

U2 - 10.1016/j.electacta.2010.11.070

DO - 10.1016/j.electacta.2010.11.070

M3 - Article

SN - 0013-4686

VL - 56

SP - 2213

EP - 2220

JO - Electrochimica Acta

JF - Electrochimica Acta

IS - 5

ER -

Diazonium salt derivatives of osmium bipyridine complexes: Electrochemical grafting and characterisation of modified surfaces

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Keywords

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