Spectroscopic study on diverse photocatalytic systems for organic transformations

The present doctoral dissertation was dedicated to select and develop an integrated photocatalytic system, which can be applied in organic reactions performed at liquid-liquid (homogenous reaction system) or liquid-solid (heterogenous reaction system) interface inside the microfluidic channels. The scientific strategy included (i) examination of potential photocatalysts upon various reaction conditions, (ii) selection of stable photocatalytic system and (iii) its implementation towards flow photochemistry by design an exemplar prototype of microfluidic devices for chemical transformations. Demonstrated strategy consist of consecutive protocols precisely described in subsequent chapters of this thesis. First part of the discussion is concentrated on the selection of photoactive organic molecule, which can act as photocatalyst for further organic transformation. The significant efforts have been made to understand all the factors which affect the formation of stable and efficient photocatalytic system. On that basis, benzothiadiazole derivative compound is proposed as an environmentally friendly photocatalyst applicable in a simple dehalogenation and C-C bond formation reactions of thiophene compounds, as well as in photo-controlled polymerization reaction of methacrylate monomers. Subsequently, to expand the scope of the photoredox catalysis towards flow technologies, the extensive spectroscopic studies on selected photocatalytic system, forming at the liquid-liquid and the solid-liquid interfaces inside the microchannel, were performed. This study allowed to design an exemplar prototype of microfluidic device, which can work upon homogenous and heterogeneous reaction conditions. At the end, the potential application of inorganic photocatalyst towards flow photochemistry is briefly discussed. The ruthenium (Ru(bpy)2CN2) complex with cyanide ligands (CN-) is consider as a potential molecular module that may provide desire architecture of photocatalytic systems, especially under microfluidic conditions due to its self-assembling properties.