No abstract

The characterization of commercially available Corning ® Lab Photo Reactor by actinometry at different wavelengths (365, 385, 405 and 475 nm) using azobenzene E ↔ Z photoisomerization is reported. By comparison with photon fluxes determined externally using a radiometer, this method based on NMR spectroscopy is rapid, cheap, robust, reproducible and can applied to UVA-visible range, compared to previously described chemical actinometric protocols. Recalculation of isatin N 2 -phenylhydrazone isomerization quantum yield at 405 nm gave almost the same value as the literature data ( Φ = 0.0013) and confirmed the robustness and applicability of this methodology.

Dedicated to Professor E. Peter Kündig on the occasion of his 75th Birthday (E)-Azobenzene is introduced as a suitable chemical actinometer in the visible spectral range (440 -540 nm) for photon flux determination of fluidic microphotoreactors or for assessing efficiency of visible light photoinduced reactions, its evaluation is straightforward without tedious analytics. Photoisomerization quantum yields (Φ E ! Z ) of (E)-azobenzene were accurately determined upon irradiation at several wavelengths and in different solvents based on well-known diarylethene.