P1.5 Coupled operando NMR and UV-vis spectroscopy of CO2 activation reactions
Supervisors:
Topic and overall goal:
The study of reaction mechanism strongly relies on the acquisition of meaningful experimental data that mirror the processes occurring at the molecular level, i.e., the elementary steps of a catalytic cycle. Although this is difficult to realize due to the short-lived nature of intermediates, the typically low catalyst concentrations, or the technical limitations of certain spectroscopies, several approaches were described in the past that allow for the real-time monitoring of catalytic reactions using well-established spectroscopic techniques such as NMR, UV-Vis, EPR, or vibrational spectroscopy. The implementation of low-cost, compact instruments would be of particular interest to allow non-expert users to monitor reactions in the environment of a standard preparative laboratory. The changes of spectra with time and concentration of compounds call for chemometric analysis, which can extract and assign spectral signatures to specific species and to determine the concentrations of these species in dependence of the considered parameters. In the past, this has been demonstrated by the Neymeyr group for simple organic transformations. A setup for low-field benchtop 1H and 31P NMR spectroscopy in flow mode that can be used for non-invasive monitoring of stoichiometric and catalytic transformations involving highly sensitive transition metal complexes is available in the Beweries group. Furthermore, the use of UV-Vis spectroscopic data to determine catalytic rates and stability constants is a well-established approach that was successfully used at LIKAT in the past.