Papers by Keyword: Photochromism

Abstract: A novel photochromic diarylethene 1a has been synthesized. Its photochemical properties, including photochromic behavior and kinetics, have been investigated in detail. The result indicated that the Diarylethene 1a changed the color from colorless to pink irradiation with 297 nm UV light, in which absorption maxima were observed at 548 nm in hexane. The photochromic reaction kinetics indicated that the cyclization processes of 1a belong to the zeroth order reaction and the cycloreversion process belong to the first order reaction. The back irradiation by appropriate wavelength visible light regenerated its open-ring isomers and recovered the original emission intensity.

Abstract: A new photochromic diarylethene based on a phenanthrene, which is named 1-{2-methyl-[5-(4-methylene-bromine) phenyl]-3-thienyl}-2-[2-methyl-5-(10-phenanthrenyl)-3-thienyl] perfluorocyclopentene 1o, was designed and constructed successfully. We used it to accomplished recording by optical storage technology as memory medium. And its properties have been discussed systematically, including photochromic both in dichloromethane solution and in PMMA film and kinetics experiments. The result indicated that its photochromic behaviors could be modulated by UV/Vis light, changing between colorless and blue in dichloromethane solution and in PMMA film, respectively. What is more, the kinetic experiments illustrated that the cyclization/cycloreversion process of this compound was determined to be the zeroth/first reaction. In addition, the results demonstrated that the unsymmetrical diarylethene compound 1o, which we had synthesized, had attractive properties for potential application in optical storage.

Abstract: A new unsymmetrical photochromic diarylethene compound, 1-(2-methyl-3-benzofuranyl)-2-[2-methyl-5-(2-methyl-6-pyridyl)-3-thienyl] perfluorocyclopentene (1o), was synthesized and its photochemical, fluorescence properties were investigated systematically both in solution and PMMA amorphous film. The photochromic reaction kinetics results indicated that the cyclization processes of 1o belong to the zeroth order reaction and the cycloreversion process belong to the first order reaction.

Abstract: A new fluorescence switch molecule based on a photochromic diarylethene and a fluorene unit was designed and constructed successfully. The compound exhibited good photochromism in acetonitrile with alternating irradiation by UV/Vis light, and the maxima absorption of its closed-ring isomer (1b) are 565nm. The open-ring isomer of the diarylethene 1a exhibited relatively strong fluorescence at 420 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 unsymmetrical photochromic diarylethene, 1-[2,4-dimethyl-5-thiazolyl]-2-[2-methyl-5-(3-4-trifluoromethylphenyl)-3-thienyl] perfluorocyclopentene (1o) was synthesized, and its properties, such as photochromism in solution as well as in poly-methylmethacrylate (PMMA) amorphous film, and fluorescence properties were investigated in detail. The results showed the compound exhibited good photochromism in hexane solution and in PMMA amorphous film, the maxima absorption of its closed-ring isomer 1c are 490 nm and 495 nm respectively. The open-ring isomer of the diarylethene 1o exhibited relatively strong fluorescence at 449 nm in hexane solution (2 × 10^-5 mol/L) when excited at 330 nm and at 438 nm in PMMA amorphous film when excited at 280 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light.

Abstract: A new unsymmetrical photochromic diarylethene 1-[2-methyl-5-(1,3-difluorophenyl)-3-thienyl]-2-[2-methyl-5-(4-methoxylphenyl)-3-thienyl] perfluorocyclopentene has been synthesized,which a methoxyl group was substituted at the para-positions of the terminal phenyl ring. The photochromism of this compound was investigated, the results showed that this compound exhibited reversible photochromism, inducing cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in a PMMA film. When irradiated 297 nm UV light, in hexane solution the maximum absorption was observed at 289 nm and 588 nm in opening-ring form and in close-ring form, respectively.

Abstract: A new unsymmetrical photochromic diarylethene compound, 1-(2-Methyl-3-benzothiophene)-2-(5-(4-ethynyl)-2-methylthiophen-3-yl)Perfluorocyclopentene (1o),was synthesized and its photochemical, fluorescence properties were investigated systematically both in solution and PMMA amorphous film. The results showed that this compound exhibited reversible photochromism, changing from colorless to pink after irradiation with 297 nm UV light both in solution and in PMMA amorphous film. The photochromic reaction kinetics indicated that the cyclization processes of 1 belong to the zeroth order reaction and the cycloreversion process belong to the first order reaction.

Abstract: A novel photochromic diarylethene based on a six-membered pyrimidine moiety 1-(2,4-dimethoxyl-5-pyrimidinyl)-2-[2-methyl-5-(4-n-pentylbenzene)-3-thienyl] perfluorocyclopent-ene has been synthesized. Its properties, including photochromic behavior and fluorescent properties, have been investigated. The compounds exhibited remarkable photochromism, changing from colorless to red after irradiation with UV light both in solution and in PMMA film. The fluorescence had a remarkable initial increase with subsequent dramatic decrease with increasing concentration. The results indicated that the pyrimidine moiety played a very important role during the process of photoisomerization reactions.

Abstract: A new asymmetry photochromic diarylethene based on a phenanthrene, which is named 1-{2-methyl-[5-(4-methylene-hydroxyl) phenyl]-3-thienyl}-2-[2-methyl-5-(10-phenanthrenyl)-3-thi-enyl] perfluorocyclopentene 1o, was designed and constructed successfully. And its properties have been discussed systematically, including photochromic, HPLC, concentration effect and fluorescent switch. The result indicated that its photochromic behaviors could be modulated by UV/Vis light, changing between colorless and violet in dichloromethane solution, respectively. What’s more, it could also response to various concentrations, with emission maximum density 5 × 10^-5 mol L^-1. In addition, the optical switch experiment illustrated that the diarylethene 1 functioned as a remarkable fluorescent switch, which fluorescent modulation efficiency was 63% in the photostationary state.

Abstract: A new unsymmetrical photochromic diarylethene [1-(1,2-dimethyl-cyano-3-pyrrole)-2-(2-methyl-5-thienyl-3-thienyl] perfluorocyclopentene (1o) has been synthesized, and its photochromic reactivity, fluorescent were also investigated. The results showed this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light in solution,Diarylethene 1 changed the color from colorless to purple upon irradiation with 297 nm UV light, in which absorption maxima were observed at 585 nm in hexane.