Synthesis and study of new photochromic halogen-substituted spiropyrans of the indoline series

New indoline spiropyrans containing chlorine and bromine atoms in position 5 of the indoline moiety of the molecule as a substituent were synthesized and studied. The structures of the synthesized compounds were confirmed by NMR and IR spectroscopy. The molecular structure of the chlorine-substituted derivative was determined by X-ray diffraction analysis, and intermolecular interactions in the crystal were studied using the CrystalExplorer21.5 software package. The spectral kinetic studies revealed photochromic properties of novel spiropyrans in an acetonitrile solution. The photoelectrochemical characteristics of dye-sensitized solar cells (DSSC) made from the synthesized compounds before and after UV irradiation were studied in comparison.