The electrochemistry and cytotoxicity of marcanine A were investigated by electrochemical, computational and cellular studies.

A thien-2-yl substituted, electron-rich phenothiazine has been converted over several steps into a redox active sol-gel precursor. Following a fluoride-catalyzed synthesis, a phenothiazine-based mesoporous hybrid organosilica was obtained. The electrochemical behavior and the luminescence properties of the immobilized chromophore have been studied using solid state fluorescence spectroscopy, electron paramagnetic resonance spectroscopy (EPR) and solid state voltammetry (CV and DPV). The influence of both the presence of fluoride anions and the acidic pH during the material synthesis were explored by means of scanning and transmission electron microscopy (SEM and TEM), X-ray powder diffraction (XRD) and nitrogen physisorption measurements. While a combination of acidic pH and fluoride was found necessary for the material formation, partial cleavage of the precursor was observed. Data obtained from both the chemical as well as the electrochemical oxidation/reduction of the immobilized PT dye indicates the formation of an organic layer containing several species inside the pore channels.

Optrodes based on Prussian blue (PB) are promising for hydrogen peroxide detection within PEMFCs to study the Membrane-Electrode-Assembly degradation. The PB film is however required to sustain the harsh environment of PEMFCs. In this work, PB films were deposited through different conditions and soaked in Phosphate-Buffer-Solutions with pH 2 at elevated temperatures for a day. These PB films were characterized using FTIR to analyze their stability following PBS processing at operating temperature and pH corresponding to an operating PEMFC. The PB film prepared using the single-source-precursor at the temperature of 60 • C is found to be the most stable.

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Developing a hydrogen peroxide (H2O2) sensor able to measure small concentrations of H2O2 in-situ is crucial to understanding the degradation mechanisms that take place in the Membrane-Electrode-Assembly of a PEM-fuel cell. Fiber optic sensing probes based on Prussian blue (PB) are promising for this application. The PB film is however required to sustain the harsh environment of PEM-fuel cells. In this work, Prussian blue films have been deposited at different synthesis temperatures, and using different precursors. The samples were immersed and left in a Phosphate-Buffer-Solution (PBS) at pH 2 at 80 °C for 21 hours and thereafter at 90 °C for 3 hours. These PB films were characterized using FTIR to analyze their stability following PBS processing at operating temperature and pH corresponding to an operating PEM-fuel cell. The PB film prepared using the single-source-precursor (SSP) at the temperature of 60 °C is found to be the most stable.