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Towards photo-CIDNP MAS NMR as a generally applicable enhancement method

Promotores: Prof.dr. H.J.M. de Groot, Prof.dr. J. Matysik (Universitaet Leipzig)

S. Thamarath Surendran
20 februari 2014
Thesis in Leiden Repository

Solid-state photochemically induced dynamic polarisation (photo-CIDNP) is one of the hyperpolarization techniques that tremendously enhances the sensitivity and selectivity of solid state NMR. Photo-CIDNP MAS NMR studies on entire cells of heliobacteria Hb. mobilis in both anaerobic and aerobic forms are presented in Chapter 2. This chapter demonstrates that photo-CIDNP MAS NMR can be applied as an analytical tool directly on to cells and bacteria even if no further purification is known or possible. To improve the knowledge of the solid-state photo-CIDNP effect, field dependencies are measured over large ranges (Chapter 3). The electron spin density distribution in the 3P donor triplet state is constructed here using the analysis of differential relaxation mechanism and this stresses the versatility of photo-CIDNP MAS NMR as hyperpolarization method. Chapter 4 describes the first observation of photo-CIDNP MAS NM R in phototropin LOV1-C57S, overcoming an old limitation of this method to natural photosynthetic RCs. The first analytical studies on the LOV1 system in Chapter 5 provides the potential to develop photo-CIDNP MAS NMR into an enhancement method generally applicable to electron transfer proteins. In Chapter 6 this leads to a new paradigm, expecting plenty of photo-CIDNP hyperpolarization if the experiment is optimized for the LOV1 system.