The catalytic reactions were analyzed with UVvis absorption and emission spectroscopy. For thermal catalysis, 5 µM of the respective substance, 50 mM NaHCO2 and 200 µM NAD + in 1:4 mixtures of acetonitrile and water were prepared in screw cap cuvettes. For light-driven reduction experiments, 5 µM of the respective substance, 0.1 M triethylamine (TEA) in 1:4 mixtures of acetonitrile and water were prepared in screw cap cuvettes. For light-driven catalysis, 5 µM of the respective substance, 0.12 M TEA and 0.1M NaH2PO4 and 200 µM NAD + in 1:4 mixtures of acetonitrile and water were prepared in screw cap cuvettes. After a zero-point measurement, the cuvettes were transferred into a custom-made reactor equipped with cooling and LED illumination (400 nm with 14 mWcm -2 ; 470 nm with 50 mWcm -2 ). After distinct time intervals, measurements by UVvis and emission spectroscopy were done.