Molecular structure controlled self-assembly of pyridine appended fluorophores: multi-stimuli fluorescence responses and fabricating rewritable/self-erasable fluorescent platforms

Abstract

Pyridine appended structural isomers showed a planar or propeller conformation dependent molecular self-assembly, fluorescent polymorphs, stimuli-responsive fluorescence switching and halochromism.

Mechanofluorochromism of (D–π–)2A-type azine-based fluorescent dyes

“…In particular, the intermolecular MFC (inter-MFC) based on reversible changes in molecular orientation and arrangement of dye molecules is superior in durability to the intramolecular MFC (intra-MFC) based on reversible changes in the chemical structures of dye molecules by cleavage and reconstruction of chemical bonds during the grinding–heating process, and thus, the inter-MFC is expected to be applicable to rewritable photoimaging and electroluminescence devices. 8–70 Among various types of fluorescent dyes possessing the mechanofluorochromic properties, donor–π–acceptor (D–π–A)-type fluorescent dyes composed of an electron-donating moiety (D) and an electron-withdrawing moiety (A) connected by a π-conjugated bridge exhibit intense photoabsorption and fluorescence emission properties based on the intramolecular charge transfer (ICT) excitation from the D moiety to the A moiety. 11–33 Thus, the dipole moments as well as photoabsorption ( i.e.…”

Multi-stimuli programmable FRET based RGB absorbing antennae towards ratiometric temperature, pH and multiple metal ion sensing

“…The tunability of spectral properties of model antennae RB 6, GB 12 and nal RGB antenna 1 with different stimuli inspired us to utilize these antennae as switchable uorescent inks. [72][73][74][75][76][77][78][79] Firstly, antenna-poly(methyl methacrylate (PMMA) composites were prepared by dissolving RB 6, GB 12 and RGB 1 (c $ 10 À3 M) and PMMA (1 wt%) in chloroform. Filter paper with text written with RB 6-PMMA composite appeared yellowish green under normal light which on exposure to TFA changed to an olive green colour and comes back to the original colour aer $5 minutes (Fig.…”

Luminescent polymorphic crystals: mechanoresponsive and multicolor-emissive properties

“…7c). 76 Four polymorphic crystals 17-G, 17-Y, 17-O, and 17-R exhibited green, yellow, orange, and red fluorescence, respectively. In response to mechanical or thermal stimuli, polymorphs 17-Y, 17-O, and 17-R were converted to 17-G, which should be the most stable polymorph.…”