Solvent systems room-temperature ionic liquids, electronic

Electrocatalytic ORR carries out in three pathways the 1-electron transfer pathway, producing superoxide ion the 2-electron transfer pathway, producing hydrogen peroxide and the 4-electron transfer pathway, producing water. In a non-aqueous aprotic solvent system, a room-temperature ionic liquid system, and on specific transition-metal, macrocyclic-compounds-coated graphite electrodes in alkaline solutions, 1-electron reduction can be observed. Carbon materials, quinone and derivatives, mono-nuclear cobalt macrocyclic compounds, and some chalcogenides can only catalyze 2-electron ORR. Noble metal, noble metal alloy materials, iron-macrocyclic complexes, di-nuclear cobalt macrocyclic complexes, some chalcogenides, and transition-metal carbide-promoted Pt catalysts can catalyze 4-electron reduction. 

The aim of this chapter also is the introduction of the photo physical study of model system ( 3-carotene in RTILs) mimicking very well spectroscopic data of this photosynthetic pigment in situ in the photosynthetic system Unique fluorescence properties of P-carotene in room temperature ionic liquids (RTIL) (Bialek-Bylka et al., 2007) and new (P-carotene) electronic states (3Ag- and 1B -) of both impxjrtant in photosynthesis isomers all-frans and 15-cis in ionic liquid with dimethylformamide (DMF) were found (Bialek-Bylka et al., 2008) and also a sensor detecting the methoxy group in the cation part of imidazolium ionic liquid was developed by us (Pawlak et al., 2009). In order to determine a detailed answer to the unique fluorescence properties, aroimd 100 times higher fluorescence yield of P-carotene in (ILl) (l-methyl-3-octyloxymethylimidazolium tetrafluoroborate) than in standard solvent n-hexane, the designed structures of RTILs were synthesized and carefully purified 1-methyl-3-octyloxymethylimidazolium tetrafluoroborate (ILl), l-methyl-3-... 

---