Mono-bisthienylethene ring-fused versus multi-bisthienylethene ring-fused photochromic hybrids

Novel bisthienylethene-based tetraazaporphyrin and phthalocyanine hybrids (BTE-TAPs) were prepared as photo-switching molecules. All new compounds were characterized by mass spectrometry (MS), H-1 NMR spectroscopy, elemental analyses, UV-vis absorptions, and luminescence spectroscopy. All BET-TAP compounds undergo open-to-closed and closed-to-open ring photoisomerizations in different quantum yields by irradiation with 365 nm or 730 nm light. The near-IR luminescence of the hybrids can be regualted in a reversible manner by the photoisomerizaton of the bisthienylethene moiety. These compounds are useful as fluorescent probes and as non-destructive readouts for erasable memory media. The phosphorescent BTE-TAP-Pt-II complex was also prepared, and its photochromism and changes in phosphorescence in a polycarbonate film were studied. These properties could give rise to other practical used of BTE-TAP hybrids.