Photo-and thermochromic spiranes. 29. New photochromic indolinospiropyrans containing a quinoline fragment

A new photochromic spiropyran of the indoline series, containing a quinoline fragment, has been synthesized. The photochromic properties of the spiropyran and its iodomethylate have been studied. Features of the molecular structure of the compounds were determined by X-ray structural investigations. It was established that the pyridopyran fragments of the cations in the crystal of the iodomethylate salt, unlike those in the crystal of the neutral spiropyran, emerge from 2₁-stacks, disposed jointly with I⁻ ions, which causes their higher mobility and aids the course of reversible photoconversions on UV irradiation in solution. For Part 28 see [1]. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 690–702, May, 2007.