Device for automated screening of irradiation wavelength and intensity – investigation of the wavelength dependence of photoreactions with an arylazo sulfone in continuous flow

Abstract

We introduce a device that allows programmable, automated changes of the irradiation wavelength and intensity for use with a continuous-flow photoreactor. Combined with parallel chromatographic analysis, the set-up enables systematic screening of photoreactions in a remarkably short time frame. This is demonstrated by investigating the photoconversion of an arylazo sulfone under different reaction conditions, with and without the use of an additive. Data obtained from a series of systematic wavelength screenings at defined irradiation intensity reveal a previously unknown intermediate and disclose a new, wavelength-dependent reaction pathway. Our study shows how systematic screening of the wavelength and irradiation intensity can contribute to the fundamental understanding of photochemical reactions.