Studies on photochromism of a thermally stable fulgide in the crystalline state: x-ray crystallographic investigation of (E)-2-isopropylidene-3-(1-naphthylmethylene)succinic anhydride

Abstract

(E)-2-Isopropylidene-3-(1-naphthylmethylene)succinic anhydride, C₁₈H₁₄O₃, M_r=278.31, monoclinic, P2₁/c, a=13.408 (1), b=8.762 (1), c=13.431 (1) Å , β=117.50 (1)°, V=1399.5 (3) ų, Z=4, D_m=1.32, D_x=1.321 Mg m^-3, Cu Kα, λ=1.5418 Å, μ=0.69 mm^-1, F(000) = 584, T=298 K, R=0.057 for 1777 observed reflections. The electrocyclic ring closure that the title compound undergoes in the solid state is viewed in terms of relevant geometrical parameters. The photochromism of the compound observed in the solid state appears to occur at defect sites, surfaces and microcavities.