Single-wavelength visible-light-induced reversible isomerization of stiff-stilbene under dynamic covalent control

Abstract

Formylation of stiff-stilbene enables isomerization by visible instead of UV light, as is monitored by UV-vis and 1H NMR spectroscopy. Further, it allows dynamic covalent imine formation, which gives rise to slightly blue-shifted absorbance. As a result, the irradiation wavelength that is used to promote E -> Z isomerization for the formylated species, causes the opposite Z -> E isomerization for the imine derivative. This feature can be used to produce either isomer with the same light source under control of imine formation and hydrolysis. Single crystal X-ray analysis and TD-DFT calculations provide structural and electronic insight.