Structure, Reactivity, Spectra, and Redox

Structure, Reactivity, Spectra, and Redox Properties of Cobalt(III) Hexaamines Philip Hendry and Andreas Ludi... 

STRUCTURE, REACTIVITY, SPECTRA, AND REDOX PROPERTIES OF COBALT(III) HEXAAMINES... 

Abstract Inorganic polysulfide anions and the related radical anions S play an important role in the redox reactions of elemental sulfur and therefore also in the geobio chemical sulfur cycle. This chapter describes the preparation of the solid polysulfides with up to eight sulfur atoms and univalent cations, as well as their solid state structures, vibrational spectra and their behavior in aqueous and non-aqueous solutions. In addition, the highly colored and reactive radical anions S with n = 2, 3, and 6 are discussed, some of which exist in equilibrium with the corresponding diamagnetic dianions. 

The feasibility of on-line electrochemistry mass spectrometry in the study of electrode processes has recently been demonstrated by Heitbaum et al. . We have tested the potential of on-line mass spectrometry in the study of redox reactivity of biological compounds with uric acid as a probe. Electrochemical oxidation of uric acid has been studied extensively . The scheme in Figure 6 shows the electrochemical oxidation pathway of uric acid and indicates intermediates and products which were identified by on-line electrochemistry thermospray mass spectrometry (EC/TSP/MS/MS) . In our studies, tandem mass spectrometry (MS/MS) was used to obtain structurally informative fragmentation patterns (daughter spectra) of standards for comparison to the mass spectra of intermediates and products obtained by EC/TSP/MS/MS. This, for example, allowed identification of allantoin through its characteristic daughter spectrum. It also allowed confirmation of the structural features of the intermediate, bicyclic carboxylic acid, which apparently forms from the imine alcohol in the oxidation of uric acid. The intermediates and products which were identified in this way are indicated in the scheme, and mass spectral results are summarized in Table 1. 

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