Chemistry Department Seminar

CuTCNQ Studies
Use of Electrochemical Scanning Probe Studies to characterize the following aspects of semi-conducting CuTCNQ chemistry will be described.
(I) The two known phases of CuTCNQ can be probed by SECM in the feedback mode by exploiting the large differences in their conductivity.
(II) Films of pure phase II material or mixtures of the CuTCNQ phases can be mapped using feedback mode SECM. However, that the packing density of the individual CuTCNQ crystals in a film structure influences the SECM feedback response.
(III) The SECM method enables the surface of single crystals of TCNQ to be modified in a controlled manner to produce highly dense and micrometer sized regions of semiconducting phase I CuTCNQ nanorod crystals by a nucleation and growth mechanism. This method involves the localized reduction of solid TCNQ to TCNQ- by aqueous phase reductant generated at a SECM ultramicroelectrode tip by reduction of , coupled with the incorporation and reduction of ions also present in the aqueous electrolyte.

Ionic Liquid Studies
Traditionally, voltammetric studies are undertaken on redox active materials dissolved in water, or an organic solvent, in order to understand the thermodynamic and kinetics associated with the electron transfer process, chemical reactions coupled to the electron transfer process and interactions with the electrode surface and solvent. However, many new media are now available for electrochemical investigations. An account of the electrochemistry of cis and trans isomers of Mn(CO)2(CN)(2-Ph2PCH2PPh2)(P(OPh)3) will be given in order to compare voltammetric data obtained in dissolved and solid state formats and illustrate: the use of ionic liquids in electrochemistry; the use of small volume isomer liquid techniques; the use of ionic liquid-aqueous interface in electrochemistry; and the influence of the medium on electron transfer and first order cis+ trans+ chemical isomerization processes.