Photo-and thermochromic spiranes 30*. Comparative study by X-ray structural analysis of the structure of spiropyrans of the indoline series containing a condensed furan fragment

Abstract

The structure of an indoline spiropyran of molecular formula C29H33NO2 has been studied by X-ray crystallographic analysis. Structural parameters have been determined for this spiropyran, containing a condensed furan fragment with a tert-butyl group, in comparison with the structure of other spiropyrans of this series. The observation in the absorption spectrum of a photoinduced cis-cis isomer is linked with its stabilization by the steric effect of the bulky tert-butyl group and the strength of barriers at 77 K.