Study And Application Of Electrochemical Interfaces With A Tunable Kinetic Barrier By Self-Assembling Dithiols And Gold Nanoparticles

In the thesis, self-assembled monolayers of organomercaptans confined to Au surfaces were studied with Photoelastic Modulation Infared Reflection Absorption Spectroscopy(PEM-IRRAS),Quartz Crystal Microbalance(QCM) and electrochemical methods.Series of rigid-rod thiols such as 1,4-bis(methanethiol)benzene (MTB), 4,4 -bis(methanethiol)biphenyl (MTP) and 9,10-bis(methanethiol)anthracene (MTA) with Aromatic structure were synthesized and characterized by IR and NMR. Based on these rigid Aromatic dithiols SAMs, nanogold modified Au electrode can be obtained and be used to detect biomacromolecules.Nanogold sol was characterized with TEM and Malvern 3000HS Zeta Size. And the 2D structure formed by dithiols and gold nanoparticles was observed with TEM.A new strategy was presented for construction of an electrochemistry interface with a tunable kinetic barrier by self-assembling rigid-rod dithiols and gold nanoparticles.Rigid-rod dithiols form assemblies in which one thiol group binds to the surface of Au electrode while the second thiol moiety projects upward at the exposed surface of the SAM.The SAMs were analyzed using PEM-IRRAS and QCM.The kinetic barrier of this self-assembled rigid-rod dithiols was modified by gold nanoparticles that were self-assembled by Au-S bond.The electrochemistry of fenicyanide redox reaction was used as a marker to probe the interface.The capacity at the solution/electrode interface was obtained with two methods.Cyclic voltammetry (CV) , different pulse voltammetry (DPV) were used to study direct electrochemistry of cytochrome c on the nanogold modified electrodes based on dithiols.The results showed that direct electron transfer occurred between cytochrome c and the electrodes, and the quasi-reversible electrode process was diffusion-controlled.Series of rigid-rod organosulfur compounds with schiffbase conjugated structure were synthesized and characterized by IR.Self-assembly of these organomercaptans confined to Au surfaces has been used to study the heterogeneous electron transfer.