The reaction of N-methyl-1,2,4-triazoline-3,5-dione (MeTAD) with anisole in the presence of trifluoroacetic acid affords unexpected disubstituted urazole products instead of the expected monosubstituted urazole as typically observed in the reactions of MeTAD with other substituted benzenes. Our investigation into the mechanism of formation of these disubstituted products suggests that MeTAD is capable of further reaction with the initially formed monosubstituted urazole to afford a persistent urazole radical. The identity of this radical has been established by UV-vis spectroscopy, the nature of its self-dimerization reaction, and via independent generation. Electrochemical oxidation of this radical was carried out, and the resulting diazenium ion was demonstrated to be reactive with added substituted benzenes, including anisole. When oxidation was carried out chemically using thianthrenium perchlorate in the presence of anisole it was shown to produce the same disubstituted products (and in the same ratio) as observed in the acid-catalyzed reaction. A common diazenium species is proposed to be active in both cases. We also report the synthesis and characterization of three interesting tetrazane dimers resulting from unstable urazole radicals.

Flavonoids have been studied extensively for their antioxidant properties. Specifically, the flavonoids in tea, such as catechin and epigallocatechin gallate, have been shown to have positive health effects. These compounds are also oxidizable, so the concentrations of these compounds in a given kind of tea can be determined using cyclic voltammetry. Green, black, oolong, and herbal teas were each diluted using pH 7.0 phosphate buffer, analyzed using cyclic voltammetry, and compared to the standards of epigallocatechin gallate, catechin hydrate, and catechol. The effect of brewing temperature on the concentration of catechins was also examined. Students learned about the common flavonoids in tea and the effect of brewing temperature on the concentration of catechins in solution.

The use of enzymatically modified electrodes for the detection of glucose or other non-electrochemically active analytes is becoming increasingly common. Direct heterogeneous electron transfer to glucose oxidase has been shown to be kinetically difficult, which is why electron transfer mediators or indirect detection is usually used for monitoring glucose with electrochemical sensors. It has been found, however, that electrodes modified with single or multi-walled carbon nanotubes (CNTs) demonstrate fast heterogeneous electron transfer kinetics as compared to that found for traditional electrodes. Incorporating CNTs into the assembly of electrochemical glucose sensors, therefore, affords the possibility of facile electron transfer to glucose oxidase, and a more direct determination of glucose. This chapter describes the methods used to use CNTs in a layer-by-layer structure along with glucose oxidase to produce an enzymatically modified electrode with high turnover rates, increased stability and shelf-life.

Alkanethiol self-assembled monolayers of three different chain lengths were used to immobilize glucose oxidase onto gold disk electrodes and the effect of the length on the kinetics of the electron-transfer reaction were investigated. 6 – mercaptohexanoic acid and 9 – mercaptononanoic acid was synthesized to provide a chain length shorter then the commercially available 11 – mercaptoundecanoic acid. The surface coverage of these SAMs, the detection sensitivity, and enzyme kinetics were investigated using cyclic voltammetry. Results showed that SAM of the 6-mercaptohexanoic acid had a higher degree of surface coverage as well as more efficient enzyme kinetics than expected.

In this issue we examine diversity, inclusion, and equity through several different lenses. This issue is of continuing importance to ECS, science, and the greater world population.