Papers by Author: Wei Jun Liu

Abstract: A novel unsymmetrical diarylethene derivative 1-[2-methyl-5-(4-pyridine)-3-thienyl]-2-[2-methyl-5-(4-hydroxylphenyl)-3-thienyl]hexafluorocyclopentene (1a) was successfully synthesized. The properties of the compound, including photochromic and fluorescence properties of the diarylethene were also investigated systematically. The results showed that absorption maxima of this compound were observed at 606 nm in methanol and at 612 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. In methanol solution, the open-ring isomer of the diarylethene 1 exhibited relatively fluorescence at 499 nm when excited at 414 nm. This new photochromic compound also exhibited remarkable optical storage character.

Abstract: A novel unsymmetrical diarylethene derivative bearing both indole and thiophene moieties, in which a cyanol group was substituted at the meta-positions of the terminal phenyl ring, was synthesized. At the same time, its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film, and its absorption maxima were observed at 592 nm in hexane and at 607 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. The fluorescence intensity of diarylethene decreased dramatically along with the photochromism from open-ring isomer to closed-ring isomer upon irradiation with 297 nm UV light in PMMA. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 426 nm when excited at 350 nm.

Abstract: An unsymmetrical diarylethene derivative bearing both benzothienyl and thienyl moieties, in which a malononitrile group was substituted at the 5-position of the thienyl ring, was synthesized. This compound undergo a reversible electrocyclic rearrangement, generating strongly colored closed-ring isomer upon irradiation with UV-light which show nonfluorescence, while exposure to light in the visible range triggers the cycloreversion to the colorless open-ring form that exhibits strong fluorescence properties. This properties of molecular photochromism were developed that showed both photo switches and fluorescence switches. The erasable and rewritable photo-images on this photochromic diarylethene were successfully demonstrated. This developments are crucial for fundamental research and eventual technical application for high-density optical data storage.

Abstract: A new photochromic compound 1-(2-ethyl-3-benzothienyl)-2- (2-n-hexyl-5-formyl-3-thienyl) perfluorocyclopentene (1a) was synthesized, its photochromic properties were examined, the result indicated that the color of the compound 1a changed from colorless to a blue one upon irradiation with 297 nm UV light, a new absorption maxima were observed at 583 and 594 nm in hexane and PMMA film, respectively. The new photochromic compound also exhibited remarkable holographic optical recording character.

Abstract: A new photochromic diarylethene 1-(3,5-dimethyl-4-isoxazolyl)-2-[2-methyl-5- (3-chlorophenyl)-3-thienyl]perfluorocyclopentene (1o) has been synthesized. Its properties, including photochromism and fluorescence were investigated in detail. It underwent reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in hexane and in PMMA. The results showed that this compound exhibited reversible photochromism and good fluorescent switching after irradiation with UV light and visible light.

Abstract: A new photochromic compound 1-(2-ethyl-3-benzothienyl)-2- (2-n-propyl-5-formyl-3-thienyl) perfluorocyclopentene (1a) was synthesized, its photochromic properties were examined, the result indicated that the color of the compound 1a changed from colorless to a blue one upon irradiation with 297 nm UV light, a new absorption maxima were observed at 578 and 587 nm in hexane and PMMA film, respectively. The diarylethene 1a exhibited relatively strong fluorescence in hexane solution and the fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light. This new photochromic compound also exhibited remarkable holographic optical recording character.

Abstract: An unsymmetrical diarylethene derivative bearing both phenyl and thiophene moieties, in which a methoxyl group was substituted at the para-positions of the terminal phenyl ring, was synthesized. At the same time, its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film, and its absorption maxima were observed at 497 nm in hexane and at 510 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 408 nm when excited at 361 nm.

Abstract: A novel photochromic diarylethene based on isoxazole moiety was synthesized and its photochromic and fluorescent properties were also 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 isoxazole moiety played a very important role during the process of photochromic reaction for the diarylethene derivative.

Abstract: A new blue photochromic diarylethene compound, 1-[2-methyl-5-aldehydeyl-3-thienyl]-2- [1,2-dimethyl-5-cyanoyl-3-pyrroleyl]perfluorocyclopentene (1a), was synthesized and its photochemical properties, such as photochromism in solution and in PMMA amorphous film, fluorescence and optical storage properties were investigated in detail. The results showed that it can be useful in fluorescence molecule switch, scale optoelectronics and potential use for data storage.

Abstract: A novel photochromic diarylethene, 1-(2-ethyl-benzothiophen-3-yl)-2-(2-methyl-5-(2-cyanophenyl)thien-3-yl)perfluorocyclopentene(1o) was synthesized, and its photochromic and fluorescent properties were investigated. This compound exhibited reversible photochromism, changing from colorless to purle after irradiation with UV light both in solution and in poly-methyl methacrylate (PMMA) amorphous film. Also, it exhibited remarkable fluorescence switching in the solid state. When we used diarylethene 1c/PMMA film as recording medium, rewritable holographic optical storage was performed successfully. The results demonstrated that the diarylethene compound had attractive properties for polarization holographic optical recording, such as high photosensitivity, high spatial resolution, excellent fatigue-resistance.