Molecular Photogearing Systems and Photoluminescent Aggregates Based on the Hemithioindigo-Chromophore

The first part of this thesis elaborates on the synthesis and analysis of a photogearing system employing the hemithioindigo chromophore as photo-addressable drive train for correlated rotations of double- and single bonds. Therefore, six isomeric states A, B, B’, C, D and D’ are studied by achiral and chiral analytic methods and all thermal and photochemical interconversions between given states are quantified revealing unprecedented photoinduced molecular gearing within the system. Apart from providing direct evidence for the presence of molecular photogearing by means of LED-coupled low-temperature NMR spectroscopic analysis, a novel LED-coupled low temperature HPLC (LED-LT-HPLC) setup for the chiral separation and in situ irradiation of enantiomeric analytes was designed and constructed to study photoreactions starting from and leading to enantiomeric states. Following the associated newly developed chromatographic methodology, the enantioselective thermal and photo-induced interconversions were traced and quantified to investigate and finally prove the existence of directional biases in the photogearing and slipping processes within the presented hemithioindigo system. The second part of this work elaborates on the synthesis and analysis of a hemithioindigo based and pyrene substituted molecular tweezer system displaying aggregation-induced emission (AIE) by excimer formation in its Z-isomeric state when solvophobically dispersed or in solid state. The (photo-)physical characteristics of the states are completely investigated by spectroscopic methods and furthermore, the thermal and photochemical interconversions between E- and Z-isomer are elucidated and quantified. Finally, the system’s capabilities to function as a host molecule for electron-deficient small molecule guests in supramolecular assemblies is investigated.