A series of small, catalytically active metallopeptides, which were derived from the nickel superoxide dismutase (NiSOD) active site were employed to study the mechanism of superoxide degradation especially focusing on the role of the axial imidazole ligand. In the literature, there are contradicting propositions about the catalytic importance of the N-terminal histidine. Therefore, we studied the stability and activity of a set of eight NiSOD model peptides, which represent the major model systems discussed in the literature to date, yet differing in their length and their Ni-coordination. UV-Vis-coupled stopped-flow kinetic measurements and mass spectrometry analysis unveiled their high oxidation sensitivity in the presence of oxygen and superoxide resulting into a much faster Ni(II)-peptide degradation for the amine/amide Ni(II) coordination than for the catalytically inactive bis-amidate Ni(II) coordination. With respect to these results we determined the catalytic activities for all NiSOD mimics studied herein, which turned out to be in almost the same range of about 2 × 106 M−1 s−1. From these experiments, we concluded that the amine/amide Ni(II) coordination is clearly the key factor for catalytic activity. Finally, we were able to clarify the role of the N-terminal histidine and to resolve the contradictory literature propositions, reported in previous studies.

Scanning transitiometry is an important calorimetric method co-invented by Jean-Pierre E. Grolier and Stanisław L. Randzio. Transitiometry enables to measure highly sensitive under high-pressure and high-temperature conditions. Nowadays, process modelling is a tool of increasing importance beyond the process of understanding process dynamics. For a valid modelling approach, a reliable data base at process conditions is required. Many processes are carried out at high temperature and pressure. Under such harsh conditions, comparatively few methods can be applied and thus limited kinetic parameters are known. Therefore, extrapolated values from low-pressure data are often utilized. Transitiometry can reduce this data gap for thermophysical properties such as heat capacity, thermal expansion coefficient and isothermal compressibility. In this paper, an overview about the method evaluation to determine thermophysical properties under high pressure using transitiometry is given. Additionally, an oversight is provided of the investigation of the decomposition kinetics of peroxides and their mixtures as another application area of high-pressure calorimetry.

Radical polymerization is widely applied in industrial production using peroxides as initiators. The high‐pressure polymerization process of LDPE is evaluated of pressures up to 3500 bar and temperature up to 300 °C. For simulations physical properties and kinetics under these harsh conditions have to be measured. Therefore, kinetic parameters such as activation energy, pre‐exponential factor and order of reaction as well as their dependence on pressure and solvent are investigated in this study with high‐pressure calorimetry using a transitiometer and DSC using high‐pressure crucibles.