saba Kanwal

3. Results and Discussion 3.1. Geometric and Structural Properties of Close and Open Isomers of Spiropyranes The geometric stability of close and open isomers of spiropyranes is estimated from their geometric properties. The optimized geometries are given in Figure 2, and the geometric parameters of spiropyranes are given in Table 1. Optimized geometries of spiropyran 1 show a clear change in bond distance between the ring closing atoms (C-O).