Daut R. Islamov

Novel paste electrodes based on phosphonium salt room temperature ionic liquids for studying the redox properties of insoluble compounds

A new carbon paste electrode is described, which contains the room temperature ionic liquid (RTIL) tri(tert-butyl)(dodecyl)phosphonium tetrafluoroborate as binder. The advantages of this electrode are a high conductivity, very wide electrochemical window (5.6xa0V from 2.7 to −2.9xa0V, one of the widest ever reported for RTILs), stability in time, and reproducibility. This RTIL-carbon paste electrode (CPE) allows determining the current-voltage characteristics of redox-active compounds. Thus, the newly synthesized insoluble compound poly-tris(μ2-1,1′-ferrocenediyl-phenylhydrophosphinato-phenylphosphinato)-iron(III) tetrahydrofuran solvate {μ2-[FeII(η5-C5H4–P(PhOO)(η5-C5H4–P(PhOOH))]3FeIII}·THF was studied, and a quasi-reversible three-electron oxidation could be observed at a potential more positive than that of ferrocene. A comparison of voltammograms on the paraffin-CPE and on the novel RTIL-CPE shows the advantages of the latter.

Redox trends in cyclometalated palladium( ii ) complexes

A series of diverse binuclear and mononuclear cyclometalated palladium(ii) complexes of different structure was investigated by electrochemical techniques combined with density functional theory (DFT) calculations. The studies including cyclic and differential pulse voltammetry, X-ray structure analysis and quantum chemical calculations revealed a regularity of the complexes oxidation potential on the metal-metal distance in the complexes: the larger Pd-Pd distance, the higher oxidation potentials. The reduction potentials feature unusually high negative values while no correlation depending on the structure could be observed. These results are in a good agreement with the electron density distribution in the complexes. Additionally, ESR data obtained for the complexes upon oxidation is reported.