Papers by Keyword: Photochromism

Abstract: A new symmetrical photochromic diarylethene 1,2-bis [2-methyl-5-(9,9-dihexyl-fluorene)-3-thienyl] perfluorocyclopentene (1o) has been synthesized, and its optoelectronic properties, such as photochromism and the fluorescence spectra of diarylethene 1o in acetonitrile solution was investigated. The maxima absorption of compound closed-ring isomer 1c is 619 nm. The open-ring isomer of the diarylethene 1o exhibited fluorescence at 390 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light,The results showed that this compound exhibited reversible photochromism and fluorescent switching in solution after irradiation with UV light and visible light.

Abstract: An asymmetrical photochromic diarylethene 1-[2-methyl-5-(3-trifluoromethyl)-3-thienyl]-2-[2-methyl-5-(9-phenanthren-e)-3-thienyl] perfluorocyclopente-ne was synthesized and its photochemical properties were investigated in detail. The results demonstrated that the compound has excellent photochromic properties and good fluoresence. The cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction.

Abstract: A novel photochromic diarylethene bearing a pyrimidine moiety, 1-(2,4-dimethoxyl-5-pyrimidinyl)-2-[2-methyl-5-(3-cyano)-3-thieny-l] perfluorocyclopentene has been synthesized. Its properties, including photochromic behavior and fluorescent properties, have been investigated. The compound exhibited remarkable photochromism, changing from colorless to blue after irradiation with UV light. The results indicated that the pyrimidine moiety played a very important role during the process of photoisomerization reactions.

Abstract: A new asymmetrical photochromic diarylethene 1-(2-cyano-1,5-dimethyl-4-pyrryl)-2-{2-methyl-[5-(4-methylene-hydroxyl) phenyl]-3-thienyl} perflu-orocyclopentene (1o) was synthesized and its photochromic properties were investigated systematically. Upon irradiation with 297 nm UV light, 1o exhibited photochromism in acetonitrile solution and in a PMMA amorphous film. The kinetic experiments showed that the cyclization and cycloreversion processes were zeroth and first order reaction, respectively. In addition, diarylethene 1o also exhibited obvious fluorescence switches along with the photochromism.

Abstract: A new unsymmetrical photochromic diarylethene 1o, which contains condensed nucleus was synthesized. Its photochromic both in hexane solution and in PMMA film and kinetics experiment were investigated in detail. The result indicated that this diarylethene had reversible photochromism, changing the color from colorless to purple in hexane solution upon appropriate irradiation with 297 nm UV light, respectively. What’s more, The kinetic experiments showed that the cyclization and cycloreversion processes were zeroth and first order reaction, respectively. This new photochromic system also exhibited fluorescence switching in acetonitrile solution.

Abstract: 1-(2,5-Dimethylthien-3-yl)-2-(4-acetyl-2,5-dimethylthien-3-yl) cyclopentene has been synthesized by a six-step procedure, such as Vilsmeier reaction, Wolff-Kishner-Huang reduction reaction, The Friedel-Crafts acylation, McMurry reaction etc. Upon alternate irradiation with 297 and 500 nm light upon 1-(2,5-Dimethylthien-3-yl)-2-(4-acetyl-2,5-dimethylthien-3-yl) cyclopentene, the absorption spectrum changes reversibly and a clear isosbestic point appears. These results suggest that the compound can undergo photochromism and do not decompose during the irradiation.

Abstract: A novel binuclear ruthenium alkynyl complexes with dithienylethene unit [{(MePh-tpy)(PPh₃)₂RuCl}₂(C≡C-DTE-C≡C)](ClO₄)₂ (II) has been synthesized and characterized by elemental analysis and NMR spectra. Its photochromic behaviors and redox properties have also been investigated. The results indicated that the open-ring isomers of the metal complex could be triggered, either by light or electricity, to convert to their closed forms.

Abstract: An unsymmetrical photochromic diarylethene which called 1-[2,5-dimethyl-3-thienyl]-2-[2-methyl-5-(4-pentylphenyl)-3-thienyl] perfluorocyclopentene (1a) was synthesized and its properties such as photochromism and fluorescence in solution as well as in a PMMA film were investigated in detail. The diarylethene has shown good photochromic behavior both in solution and in a PMMA film.

Abstract: A new unsymmetrical photochromic diarylethene compound 1a was synthesized and its photochromism were investigated. The compound exhibited good photochromism in solution and PMMA films with alternating irradiation by UV/Vis light, and the maxima absorption of its closed-ring isomer (1b) are 536 nm in hexane and 552 nm in PMMA films. The open-ring isomer of the diarylethene 1a exhibited relatively strong fluorescence at 441 nm when excited at 290 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.

Abstract: A new photochromic diarylethene compound bearing a rhodamine B unit, 1-(2-methyl-3-benzofuryl)-2-{2-methyl-5-[4-formyloxyethyl (rhodamine-B)] phenyl-3-thienyl} perfluorocyclopentene (1o) was synthesized, and its photochromic properties such as photochromism in solution as well as in a polymethylmethacrylate (PMMA) amorphous film were investigated specfically. 1o exhibits good photochromism upon alternating irradiation with UV light and visible light (> 510 nm) in hexane and a PMMA film. The kinetic experiments showed that the cyclization and cycloreversion processes were zeroth and first order reaction, respectively.