Synthesis, Photochromism, and Thermal Stability of Two New Diarylethenes Based On Spirobifluorene

Two novel spirobifluorene-diarylethenes compounds with furan (9a) and thiophen (8a) as heterocyclic aryl groups were successfully synthesized, and their structures were fully characterized with FTIR, NMR, mass spectra (MS), and elemental analysis. Their photochromic properties were examined. The results indicated that they showed good photochromic behaviors in hexane and acetonitrile. The fluorescence emission was quenched along with the photochromism from open ring to closed ring. Large fluorescence emission blue-shift was clearly observed in polar solvents. Furthermore, the thermal stability of 8a and 9a was greatly improved by introducing spirobifluorene group into the molecules. The 5% loss weight temperature of 9a was 59 degrees C higher than that of 10a without spirobifluorene.