A non-rotatory isomerization path in ethene derivatives? Investigation of a stilbenophane and protonated azobenzenophanes (“pseudo-stilbenophanes”)

Abstract

A stilbenophane and protonated azobenzenophanes (“pseudo-stilbenes”) with four –CH₂–S–CH₂– bridges in all meta-positions were synthesized. The spectroscopic and photochemical properties were investigated: excited dimer absorption spectra and for the stilbenophane also emission spectra were observed. Photochemical reactions could be identified as the [2+2] photocycloaddition for the stilbenophane; the nature of the photoproducts in the case of pseudo-stilbenes could not be established. Photo-isomerizations could not be observed which gives a negative answer to the title question.