New Photochromic Salt Spiropyrans of Indoline Series

Abstract

Synthesis, structure study, and photochromic properties of new salt spiropyrans of indoline series containing chlorine and bromine atoms in the 6'-position of the 2H-chromene moiety have been reported. The structure of the obtained compounds has been confirmed by ¹H NMR spectroscopy and X-ray diffraction analysis. The compounds are photochromic; the long-wavelength absorption maximum for photoinduced isomer shows a considerable hypsochromic shift, while the lifetime increases considerably as compared with the fluorine-containing analog.