New Photochromic Salt Spiropyrans of Indoline Series

The synthesis and study of the structure and photochromic properties of the new salt spiropyrans of the indoline series containing chlorine and bromine atoms as a substituent at the 6' position in 2H-chromene moiety are presented. The structure of the obtained compounds was confirmed by NMR 1 H spectroscopy and X-ray diffraction analysis. The compounds are photochromic; the long-wavelength maximum of the absorption band of their open photoinduced form has a significant hypsochromic shift, and the lifetime substantially increases in comparison with the fluorine analog.