/pdf/self-assembled-monolayers-of-thiolates-on-metals-as-a-form-1neb0hj3k4.pdf

Self-assembled monolayers of thiolates on metals as a form of nanotechnology.

https://is.muni.cz/el/1431/podzim2006/C7780/um/Read/2711172/SAM_str_grwth_ProgSurfSci00_151.pdf

Structure and growth of self-assembling monolayers

In this report, we evaluate the present state of the rapidly emerging field of monolayer-protected cluster (MPC) molecules with regard to their synthesis and monolayer functionalization, their core and monolayer structure, their composition, and their properties. Finally, we canvass some of the important remaining research opportunities involving MPCs.

/pdf/monolayer-protected-cluster-molecules-1mpqg67ah9.pdf

Monolayer-Protected Cluster Molecules

3.6.1. Polishing and Cleaning 2663 3.6.2. Vacuum and Heat Treatments 2664 3.6.3. Carbon Electrode Activation 2665 3.7. Summary and Generalizations 2666 4. Advanced Carbon Electrode Materials 2666 4.1. Microfabricated Carbon Thin Films 2666 4.2. Boron-Doped Diamond for Electrochemistry 2668 4.3. Fibers and Nanotubes 2669 4.4. Carbon Composite Electrodes 2674 5. Carbon Surface Modification 2675 5.1. Diazonium Ion Reduction 2675 5.2. Thermal and Photochemical Modifications 2679 5.3. Amine and Carboxylate Oxidation 2680 5.4. Modification by “Click” Chemistry 2681 6. Synopsis and Outlook 2681 7. Acknowledgments 2682 8. References 2682

/pdf/advanced-carbon-electrode-materials-for-molecular-2y6b22van0.pdf

Advanced carbon electrode materials for molecular electrochemistry.

Implicit Solvation Models: Equilibria, Structure, Spectra, and Dynamics.

The kinetics of electron transfer between a substrate gold electrode and a self-assembled monolayer formed from CH{sub 3}(CH{sub 2}){sub n-1}SH and ({eta}{sup 5} C{sub 5}H{sub 5})Fe ({eta}{sup 5}-C{sub 5}H{sub 4})CO{sub 2}(CH{sub 2}){sub n}SH were studied as a function of n, the number of methylenes in the alkyl chain tethering the ferrocene moiety to the electrode, using the indirect laser-induced temperature jump method (ILIT). For 5 {<=} n {<=} 9 the standard electron-transfer rate constants vary according to {kappa}{sub {tau}a,n=0} exp[-{beta}{sub n}n] where {kappa}{sub {tau}a,n=0} is the (extrapolated) rate constant for the electron transfer at n = 0. At {Tau} = 25{degree}C, {kappa}{sub {tau}a,n} 0 {approx_equal} 6 x 10{sup 8} s{sup -1} and {beta}{sub n} = 1.21 x 0.05. The ILIT method allows rates to be measured that are too fast to be measured by conventional chronoamperometry at a macroelectrode, which is limited to rate constants of {<=} 10{sup 4} s{sup -1}. Using a Marcus formalism, the reorganization energy, {lambda}, for the electron-transfer process at a given n was determined from the slope of an Arrhenius plot over the temperature range 15-55{degree}C. Values of {lambda} determined from Arrhenius slopes for n = 8 and 9 using ILIT are in reasonable agreementmore » with the value of {lambda} previously deduced from the potential dependence of the rate constant for n = 16. 39 refs., 13 figs., 3 tabs.« less

The Kinetics of Electron Transfer Through Ferrocene-Terminated Alkanethiol Monolayers on Gold

Rates of Interfacial Electron Transfer through π-Conjugated Spacers

We measured rate constants of thermal, interfacial electron transfer through oligophenylenevinylene bridges between a gold electrode and a tethered redox species in contact with an aqueous electrolyte using the indirect laser-induced temperature jump technique. Analysis of the distance dependence indicates that, unlike other bridges studied to date, the rate constants are not limited by electronic coupling for bridges up to 28 angstroms long. The energy levels of the bridges relative to those of the redox species rule out hopping through the bridge. We conclude that, out to 28 angstroms, the transfer is limited by structural reorganization and that electron tunneling occurs in less than 20 picoseconds, suggesting that oligophenylenevinylene bridges could be useful for wiring molecular electronic elements.

https://science.sciencemag.org/content/sci/291/5508/1519.full.pdf

Rapid electron tunneling through oligophenylenevinylene bridges.

The standard heterogeneous electron-transfer rate constants between substrate gold electrodes and either ferrocene or pentaaminepyridine ruthenium redox couples attached to the electrode surface by various lengths of an alkanethiol bridge as a constituent of a mixed self-assembled monolayer were measured as a function of temperature. The ferrocene was either directly attached to the alkanethiol bridge or attached through an ester (CO2) linkage. For long bridge lengths (containing more than 11 methylene groups) the rate constants were measured using either chronoamperometry or cyclic voltammetry; for the shorter bridges, the indirect laser induced temperature jump technique was employed to measure the rate constants. Analysis of the distance (bridge length) dependence of the preexponential factors obtained from an Arrhenius analysis of the rate constant versus temperature data demonstrates a clear limiting behavior at a surprisingly small value of this preexponential factor (much lower than would be expect...

Heterogeneous Electron-Transfer Kinetics for Ruthenium and Ferrocene Redox Moieties through Alkanethiol Monolayers on Gold

The indirect laser-induced temperature jump (ILIT) method is used to determine the acidity (pKa) of monolayers composed of 11-mercaptoundecanoic acid (MUA) self-assembled on vapor-deposited gold film electrodes in contact with either 0.10 or 1.0 M ionic strength NaClO4 electrolyte solutions. The ILIT technique may be used to measure the pKa of a surface-attached acid because the magnitude of the ILIT response is related to the potential gradient at the electrode/electrolyte interface which is, in turn, related to the extent of ionization of the acid. The relevant data are the potentials of zero ILIT response versus pH. A simple two-layer model of the acid-modified electrode/electrolyte interface and Gouy−Chapman double layer theory (modified for the onset of dielectric saturation effected by the large concentration of charge present at this interface when a substantial fraction of the carboxylic acid moieties are ionized) were employed to analyze these data. This analysis gives pKa = 5.7 ± 0.2 at 0.10 M i...

John F. Smalley

Papers

The Kinetics of Electron Transfer Through Ferrocene-Terminated Alkanethiol Monolayers on Gold

Rates of Interfacial Electron Transfer through π-Conjugated Spacers

Rapid electron tunneling through oligophenylenevinylene bridges.

Heterogeneous Electron-Transfer Kinetics for Ruthenium and Ferrocene Redox Moieties through Alkanethiol Monolayers on Gold

An indirect laser-induced temperature jump determination of the surface pka of 11-mercaptoundecanoic acid monolayers self-assembled on gold