Mono-Bisthienylethene Ring-Fused versus Multi-Bisthienylethene Ring-Fused Photochromic Hybrids

Abstract

Novel bisthienylethene-based tetraazaporphyrin and phthalocyanine hybrids (BTE–TAPs) were prepared as photo-switching molecules. All new compounds were characterized by mass spectrometry (MS), ¹H NMR spectroscopy, elemental analysis, UV-vis absorption, and luminescence spectroscopy. All BTE–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 regulated in a reversible manner by the photoisomerization 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 uses of BTE–TAP hybrids.