In this work, we present an ew synthetics trategy for fourfold-substituted perylene monoimides via tetrabrominated perylene monoanhydrides. X-ray diffraction analysis unveiled the intramolecular stacking orientation between the substituents and semicircular packing behavior.W eo bserved the remarkable influence of the substituent on the longevity and nature of the excited state upon visible light excitation.I nt he presenceo fp oly(dehydroalanine)-graftpoly(ethylene glycol)g raft copolymers as solubilizing template, the chromophores are capable of sensitizing [Mo 3 S 13 ] 2À clustersi na queous solution for stable visible light driven hydrogen evolution over three days.

Reproducibility and comparability of photocatalytic experiments are still challenging, owing to the large number of experimental parameters and their comprehensive documentation. To overcome this limitation, a modular, adaptable, and extensible photoreactor platform is reported, which enables experiments under well‐characterized, reproducible conditions. Comparability is ensured by comprehensive photonic characterization with chemical actinometry, radiometry and open documentation of the incident photon fluxes in the reaction vessels for different setups as well as the homogeneity of irradiation in multi‐reactor setups. Comprehensive documentation minimizes the need for repeated photonic characterization when modifying the setups. Experimental reproducibility within and across experiments was evaluated with studies of photocatalytic systems for hydrogen evolution, emphasizing the validity of the concept.

The aim of this study was to accurately quantify the benefit of adding extra layers to a capillary flow‐photoreactor using actinometry. A self‐built 3D‐printed FEP cap‐ illary mount was designed and each of the layers was evaluated separately. Experimental results showed that additional capillaries can be regarded as an augmented optical path length and that reflection and scattering are of minor importance for stacking of capillaries. To cope with the problem of precipitation of the ferrioxalate actinometer in intensified reactors, a new experimental method of conducting actinometric measurements with pulses was investigated and showed reasonable agreement. To make the results comparable to other literature‐known, mostly also improvised reactor setups, appropriate figures of merit (productivity, space time yield, energy efficiency and external photon efficiency) were evaluated.

Inspired by the active center of the natural [FeFe] hydrogenases, we designed a compact and precious metal‐free photosensitizer‐catalyst dyad (PS‐CAT) for photocatalytic hydrogen evolution under visible light irradiation. PS‐CAT represents a prototype dyad comprising π‐conjugated oligothiophenes as light absorbers. PS‐CAT and its interaction with the sacrificial donor 1,3‐dimethyl‐2‐phenylbenzimidazoline were studied by steady‐state and time‐resolved spectroscopy coupled with electrochemical techniques and visible light‐driven photocatalytic investigations. Operando EPR spectroscopy revealed the formation of an active [FeIFe0] species—in accordance with theoretical calculations—presumably driving photocatalysis effectively (TON≈210).

This work elaborates the effect of dynamic irradiation on lightdriven molecular water oxidation to counteract deactivation. It highlights the importance of overall reaction engineering to overcome limiting factors in artificial photosynthesis reactions. Systematic investigation of a homogeneous three-component ruthenium-based water oxidation system revealed significant potential to enhance the overall catalytic efficiency by synchronizing the timescales of photoreaction and mass transport in a capillary flow reactor. The overall activity could be improved by a factor of more than 10 with respect to the turnover number and a factor of 31 referring to the external energy efficiency by controlling the local availability of photons. Detailed insights into the mechanism of light driven water oxidation could be obtained using complementary methods of investigation like Raman, IR, and UV/Vis/emission spectroscopy, unraveling the importance of avoiding high concentrations of excited photosensitizers.