The Electrochemical and Spectral Characteristics of N, N’-di-p-Anisylamino-Substitued Phenyl Derivatives and Their Effects on Chemiluminescence
Date Issued
2011
Date
2011
Author(s)
Chen, Yuling
Abstract
We have investigated the electrochemical, spectral, and kinetic properties of the synthesized triarylamines and their cation radicals and dications. The UV/Vis spectral changes for the formation of cation radicals and dication species of these compounds were successfully observed by repeated scan of the absorption spectra at fixed voltages below their half-wave potentials. The spectral changes for the regeneration of the cation radical and then the neutral species could be observed by resetting the voltage to 0.0 V (vs. Ag/AgCl) after the dicationic species was formed. These observations allowed us to investigate the kinetics of the whole redox processes for some triarylamines. We also found that the rates for the formation of radical cations and dicationic species of these compounds increased exponentially with increasing applied voltages. The kinetic data indicate that the rate constants (k) for the conversion are strongly dependent on the individual step, the applied potential, and the identity of the substituents. Moreover, linear Hammet plots were observed for the half-wave potentials of first redox couples and the absorption maxima (both neutral and cationic species) against the substituent constant (3)Theoretical calculations have revealed that the removal of the first and second electrons from these compounds comes mostly from the nitrogen atom and the phenyl rings, respectively.
Dual chemiluminescence (CL) from the KIO4-luminol-Mn2+ system was originated from different CL pathways participated by various reactive oxygen species (ROS) such as O2-, •OH, and 1O2. It is interesting to examine how the cation radicals generated from derivatives of triarylamine affect the dual CL emission. In the presence of a strong oxidant KIO4 and a catalyst Mn2+, the formation of radical cations of triarylamines inhibited the first peak, but further enhanced the second peak. The resulting CL emission was used to determine the phenolic compounds such as dopamine, (+)-enpinephrine and flavones. These compounds are capable of reacting with ROS and radicals efficiently.
Subjects
triarylamines
electrochemical
spectral and kinetic properties
chemiluminescence
stopped-flow spectrometry
Type
thesis
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