Tianshe Yang

Photochromic Diarylethene for Two-Photon 3D Optical Storage

The photochromic diarylethene, 1, 2-bis(2-methyl-5-(3-trifluorophenyl)-3-thienyl)perfluorocyclopentene (BMTTP), was synthesized. This compound undergoes a photochromic reaction either in solution, PMMA amorphous film or in the single crystalline phase. Using this compound as recording medium, two-photon optical bit pattern storage was performed successfully by a femtosecond laser and a reflection confocal scanning-fluorescence microscope.

Synthesis of a novel dithienylethene and application to holographic optical storage

A novel photochromic dithienylethene, [1-(2-methyl-5-formyl-3-thienyl)-2-(2-methyl-5-naphthyl-3-thienyl)]perfluoro- cyclopentene (1a), was synthesized and its photochemical properties, such as photochromism in solution as well as in poly-methylmethacrylate (PMMA) amorphous film, fluorescence were investigated in detail. Dithienylethene 1a has shown good photochromic behavior both in solution and in PMMA film. Upon irradiation with 254 nm UV light, its color changed from colorless to blue, in which absorption maxima were observed at 584 nm in hexane and 596 nm in PMMA film. 1a also showed relatively strong fluorescence in different solvents when excited at 292 nm. In addition, photon-mode holographic optical storage using dithienylethene 1b as recording medium was performed successfully.

3,3,4,4,5,5-Hexafluoro-1-(2-methoxyphenyl)-2-[5-(4-methoxyphenyl)-2-methyl-3-thienyl]cyclopent-1-ene: a photochromic compound

The photochromic title compound, C(24)H(18)F(6)O(2)S, has thienyl and aryl substituents on the C=C double bond of the shallow half-chair-shaped cyclopentene ring. The planes of the two substituent rings are inclined to that of the cyclopentene ring, with dihedral angles between the mean plane of the cyclopentene ring and those of the phenylene and thienyl rings of 51.2 (1) and 51.3 (1) degrees, respectively. The molecule adopts an antiparallel conformation, with a distance between the two photoreactive C atoms of 3.717 (2) A.

1,2-Bis[5-(4-cyano­phen­yl)-2-methyl-3-thien­yl]-3,3,4,4,5,5-hexa­fluoro­cyclo­pent-1-ene: a photochromic diaryl­ethene compound

The molecules of the title compound, C29H16F6N2S2, a photochromic dithienylethene with 4-cyanophenyl substituents, adopt an antiparallel arrangement that is reponsible for photoactivity. The molecule lies on a twofold rotation axis. The dihedral angle between the nearly planar cyclopentenyl and heteroaryl rings is 142.5 (3)°, and that between the heteroaryl and benzene rings is 22.4 (3)°. The distance between the heteroaryl rings of adjacent molecules is 3.601 (2) Å, indicating a π–π interaction.

Optoelectronic properties and holographic optical recording of a dithienylperfluorocyclopentene compound having two phenanthryl units

A phenanthrenyl-substituted diarylethene derivative (1,2-bis[5-phenanthryl-2-methylthiophen-3-yl] perfluorocyclopentene, Ph-BMTFP) has been synthesized and its optoelectronic properties have been investigated. The photochromic reactivity of Ph-BMTFP was examined in hexane solution as well as in poly(methyl methacrylate) (PMMA) amorphous film. Upon irradiation with 313 nm UV light, the colorless solution turned purple, in which a visible absorption band was observed at 555 nm. In PMMA film, the new broad absorption band at lambda(max) = 580 nm appeared when it was irradiated by 313 nm UV light. The compound exhibited good fluorescence in hexane solution and its fluorescence intensity decreased along with the photochromic reactivity upon irradiation with 313 nm UV light. This property could be potentially applied to high-density optical memory with fluorescence readout method. The holographic optical storage was performed successfully using Ph-BMTFP as the recording medium and polarization multiplexing holograms recording can effectively increase the information storage capacity of the holographic data storage.

Synthesis, Property and Holographic Recording of a Photochromic Diarylethene Bearing Chlorine Atoms

A novel symmetrical photochromic diarylethene, 1,2-bis[2-methyl-5-(p-chlorophenyl)-3-thienyl]perfluorocyclop- entene (1a), has been synthesized. Its photochromic properties in solution and PMMA film were investigated. While, fluorescence properties in different solution have also been discussed. The results of the research demonstrated that it has shown good photochromic behavior and relatively strong fluorescence in different solution at room temperature. At last, using this dithienylethene as recording medium, photon-mode holographic optical storage was performed successfully.

Kinetics and Electrochemical Properties of a New Photochromic Diarylethene

A new unsymmetrical photochromic diarylethene compound, 1-[2-methyl-5-(4-cyanophenyl)-3-thienyl]-2-[2-methyl-5-(4-chlorophenyl)-3-thienyl] perfluorocyclopentene (1a), was synthesized and its photochemical properties, such as photochromism and kinetics in solution as well as in PMMA amorphous film, and electrochemical properties were investigated in detail. The results showed that the cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction, and the electrochemical switching property can be potential use for electrochemistry data storage.

1-[5-(3-Chloro­phen­yl)-2-methyl-3-thi­en­yl]-3,3,4,4,5,5-hexa­fluoro-2-(2-methoxy­phen­yl)­cyclo­pent-1-ene

The title compound, C23H15ClF6OS, has thienyl and phenylene substituents on the double-bond C atoms of the envelope-shaped cyclopentenyl ring. The aromatic systems are aligned at 55.3 (4) (thienyl) and 60.8 (7)° (phenylene) with respect to the planar C—C=C—C portion of the main central cyclopentenyl ring.

Oxidative electrochemical switching of photochromic diarylethene compounds

A series of photochromic diarylethenes compounds were synthesized and the electrochemistry and electrochemistry reaction mechanism properties were investigated. The cyclic voltammetry tests demonstrated that the colorless open-ring isomers were assigned to the unique oxidation process, but the color closed-ring isomers of these compounds were assigned to two oxidation processes. In addition, the electrochromism of diarylethene compound is observed in solution: The closed-ring reaction can be triggered by electrochemical oxidation, while the open-ring reaction must be photochemically driven. These oxidation processes properties can be useful as the oxidation processes electrochemical switching and the oxidation electrochemical switching properties of these different diarylethene isomers can be potential for electrochemistry data storages.

Photochromic diarylethene for holographic optical recording

A unsymmetrical photochromic diarylethene, 1-(2-methyl-5-phenylthien-3-yl)-2-[2-methyl-5-(3-fluorophenyl)thien- 3- yl]perfluorocyclopentene (1a), was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. The compound showed good photochromism in solution, in PMMA amorphous film and in the singlecrystalline phase upon photo-irradiation. Using the diarylethene 1b/PMMA film as recording medium and a nonpolarized He-Ne laser (633 nm, 4 mW) for recording and readout, three types of polarization holographic optical recording were carried out successfully. The results showed that different patterns can be displayed with differently polarized readout lights, which can be applied in camouflage technology.