Closed-ring Isomer Research Articles

Multi-functional ion-sensor based on a photochromic diarylethene with a 1H-imidazo [4,5-f][1,10] phenanthroline unit.

A new asymmetrical diarylethene containing a 1H-imidazo [4,5-f][1,10] phenanthroline unit was synthesized. The compound showed typical photochromism and functioned as a notable fluorescence switch upon alternating irradiation with ultraviolet (UV) and visible light. Its closed-ring isomer could be used as a selective 'naked-eye' colorimetric sensor for Cu(2+), accompanied by a notable color change from blue to colorless. Furthermore, the compound was found to be selective towards Ca(2+), Mg(2+), and Sr(2+) with significant fluorescence changes. On the basis of this characteristic, a logic circuit was constructed by utilizing both light and chemical stimuli as inputs and fluorescence intensity at 487 nm as output.

A novel colorimetric sensor based on a diarylethene derivative for selective detection of Cu(ii)

A novel photochromic diarylethene derivative with a di-2-picolylamine unit and a hydroxyl group has been designed and synthesized for the first time. The selective interaction of its closed-ring isomers with Cu2+ions was investigated systematically. The results indicated that the diarylethene derivative could be used as a colorimetric sensor for the selective recognition of Cu2+ions.

Theoretical design of solvatochromism switching by photochromic reactions using donor-acceptor disubstituted diarylethene derivatives with oxidized thiophene rings.

We have designed several diarylethene derivatives with oxidized thiophene rings and donor-acceptor substituents, which show the solvatochromism switching by photochromic reactions, using a time-dependent density functional theory (TD-DFT) method using the polarizable continuum model (PCM). It is found that in the UV-vis spectral region examined only the open-ring isomers exhibit the solvatochromism, while the closed-ring isomers do not. The mechanism of the solvatochromism behavior and its switching process are clarified from the viewpoint of the charge-transfer (CT) excitation from the donor to the acceptor substituents. We demonstrate that this CT excitation can be controlled by choosing appropriate pairs of the donor and the acceptor substituents on the basis of the orbital correlation diagram between the diarylethene derivatives and the donor-acceptor substituents, which is constructed from the topologies and the orbital energies of the molecular orbitals primarily contributing to the excitations.

A diarylethene as the SO2 gas generator upon UV irradiation.

A closed-ring isomer of a diarylethene having a sulfone group works as the reagent for SO2 gas generation with thermal stability even at 70 °C, and it rapidly reverts to the open-ring isomer and generates the SO2 gas to induce cell death upon UV irradiation.

Photoinduced cytotoxicity of a photochromic diarylethene via caspase cascade activation.

The photo-generated closed-ring isomer of bis(5-methyl-2-phenylthiazoyl)perfluorocyclopentene shows cytotoxicity to Madin-Darby canine kidney (MDCK) cells through a caspase cascade and induces apoptosis of cells.

Synthesis and Application of 1-(2-methyl-3-benzothienyl)-2-[3-methyl-2-thienyl]perfluorocyclopentene

A novel unsymmetrical photochromic diarylethene compound 1-(2-methyl-3-benzothienyl)-2-[3-methyl-2-thienyl] perfluorocyclopentene was designed and constructed successfully. Its optoelectronic properties have been discussed systematically, such as photochromic, fluorescence switch, kinetics experiments in hexane solution and PMMA. The consequences showed that this compound exhibited good reversible photochromism. The maxima absorption of compound closed-ring isomer 1c is 468nm. Upon irradiation with 297nm UV light, Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.

Synthesis and Application of 1-[2-methyl-5-(4-hydroxymethylphenyl)-3-thienyl]-2-[2-methyl-5-(4-azidomethylphenyl)-3-thienyl]perfluorocyclopentene

A new fluorescent switch based on a photochromic diarylethene, 1-[2-methyl-5-(4-hydroxymethylphenyl)-3-thienyl]-2-[2-methyl-5-(4-azidomethylphenyl)-3-thienyl] perfluorocyclopentene has been synthesized, And its properties have been discussed systematically in acetonitrile solution and in PMMA, such as photochromic, fluorescence switch and kinetics experiments, and its optoelectronic properties, The results showed that this compound exhibited reversible photochromism and the maxima absorption of compound closed-ring isomer 1c is 590 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers.

Synthesis and Photochromism Studies of 1-(2-n-butyl-3-benzothienyl)-2-[2-methyl-5-phenyl-3-thienyl] Perfluorocyclopentene

A photochromic diarylethene was synthesized and explored, The compound shown good photochromic behavior. When irradiated with UV light. the compound changed from colorless to violet, which showed a relatively strong fluorescence switch along with the photochromism from open-ring isomer to closed-ring isomer.

Synthesis and Properties of 1-(2-Methyl-3-benzothiophene)-2-[2-methyl-5-(3-fluoro-4-chloro)phenyl-3-thienyl]perfluorocyclopentene

An asymmetrical photochromic diarylethene1-(2-Methyl-3-benzothiophene)-2-[2-methyl-5-(3-fluoro-4-chloro) phenyl-3-thienyl] perfluorocyclopentene (1o) was synthesized and its phtochromic, fluorescent properties were investigated in detail. This compound exhibited remarkable photochromism, upon irradiation with 297 nm UV light, the colorless solution of 1o turned to violetred with a new visible absorption band centered at 538 nm (ε = 1.17 × 104 L mol-1 cm-1) attributable to the closed-ring isomer 1c. The kinetic experiments showed that the cyclization and cycloreversion processes were zeroth and first order reaction, respectively. Moreover, diarylethene 1o also exhibited obviously fluorescence switches along with the photochromism.The emission intensity of diarylethene 1o in a photostationary state was quenched to ca. 27% in hexane.

A highly selective fluorescent probe for Sn2+ based on a new photochromic diarylethene with a phenol-containing Schiff base unit

A novel diarylethene with a phenol-containing Schiff base unit was successfully synthesized and its multi-responsive photoswitching property was investigated by the stimulation of base/acid and light. The diarylethene showed not only normal photochromism by photoirradiation, but also abnormal photochromism by base and light stimuli. By the stimulation of sodium hydroxide, the absorption maximum of its open-ring isomer showed extraordinarily large redshift of 60 nm, accompanied with a notable color change from colorless to yellow. Subsequent irradiation with 297 nm light further caused a dramatic change in its structure transformation from the deprotonated open-ring isomer to the original closed-ring isomer. Similarly, its deprotonated closed-ring isomer returned to its original open-ring isomer upon irradiation with appropriate visible light. Its deprotonated forms could be restored by the stimulation of hydrochloric acid. Moreover, the diarylethene could be served as a fluorescence probe for recognition of Sn2+ with high selectivity.

Synthesis and Properties of 1,2-Bis[2-Methyl-5-(9,9-Dihexyl-Fluorene)-3-Thienyl]Perfluorocyclopentene

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.

Synthesis, Photochromism and Fluorescent Switch of 1-(2-Methyl-1-Benzofuran-3-Yl)-2-(2-Methyl-5-(4-Benzylazide)-3-Thienyl)Perfluorocyclopentene

A photochromic diarylethene of 1-(2-methyl-1-benzofuran-3-yl)-2-(2-methyl-5-(4-benzylazide)-3-thienyl)) perfluorocyclopentene was synthesized and its properties such as photochromism and fluorescence in solution were investigated in detail. The diarylethene has shown good photochromic behavior in solution with alternating irradiation by UV/vis light. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.

Research on Photochromic Materials with Synthesis and Properties of 1-(2-Methyl-3-Benzothiophene)-2-[2-Methyl-5-(3-Cyanophenyl)-3-Thienyl]Perfluorocyclopentene

An asymmetrical photochromic diarylethene1-(2-Methyl-3-benzothiophene)-2-[2-methyl-5-(3-cyanophenyl)-3-thienyl] perfluorocyclopentene (1o) was synthesized and its phtochromic, fluorescent properties in both solution and PMMA films were investigated in detail. This compound exhibited remarkable photochromism, upon irradiation with 297 nm UV light, the colorless solution of 1o turned to violet with a new visible absorption band centered at 535 nm (ε = 1.08 × 104 L mol-1 cm-1) attributable to the closed-ring isomer 1c. The emission intensity of diarylethene 1o in a photostationary state was quenched to ca. 32% in hexane and 43% in PMMA film.

Substituent effects on the properties of photochromic hybrid diarylethenes with a naphthalene moiety

Four new unsymmetrical photochromic diarylethenes bearing both naphthalene and thiophene moieties were synthesized, and the structures of two diarylethenes were determined by single-crystal X-ray diffraction analysis. The naphthalene ring was connected directly to the central perfluorocyclopentene ring as an aryl moiety and available to participate in photoisomerization reaction. All the diarylethenes exhibited favorable photochromism and functioned as fluorescence switches in both solution and poly(methyl methacrylate) films. The electron-withdrawing substituent significantly shifted the absorption maxima to a longer wavelength and evidently suppressed the cycloreversion quantum yield, whereas the electron-donating substituents enhanced the fluorescence quantum yield of diarylethenes with a naphthalene moiety. Furthermore, cyclic voltammograms suggested that the oxidation onsets and band-gaps of the open-ring isomers were much bigger than those of the closed-ring isomers. The results indicated that the substituents at the 5-position of thiophene ring could availably modulate their optical and electrochemical behaviors.

Theoretical explanation of the photoswitchable superhydrophobicity of diarylethene microcrystalline surfaces.

Two types of superhydrophobic surfaces which show lotus and petal effects were induced on photochromic diarylethene microcrystalline surfaces by UV and visible light irradiation and temperature control. On the surfaces showing the lotus effect, a low-adhesion superhydrophobic property is attributed to the surface structure being covered with densely standing needle-shaped crystals of the closed-ring isomer. On surfaces showing the petal effect, a high-adhesion superhydrophobic surface consists of fine needle-shaped crystals with high density together with a few rod-shaped crystals, where an invasion phenomenon occurs between these rod-shaped crystals. Furthermore, the different superhydrophobic properties of the surfaces are theoretically explained using multipillar surface models.

Effects of solvents on the growth of an asymmetrical photochromic diarylethene crystal

An asymmetrical photochromic diarylethene with one pyridine unit was synthesized, which could have two types of crystals controlled through the evaporation of either an ether solution or a hexane/chloroform (V = 1:1) solution at room temperature, respectively. The obtained open-ring isomer and closed-ring isomer of the diarylethene could be interconverted in solution, in a solid film, and even in the crystalline phase via alternating irradiation with UV and visible light. The diarylethene exhibited proton-controlling fluorescence switching behavior through alternating the stimulation of trifluoroacetic acid and triethylamine. Its fluorescence intensity could also be modulated reversibly through alternating irradiation with UV and visible light. Thus, the diarylethene could be used as a multi-addressable fluorescence switch when triggered with light and acid/base. Cyclic voltammograms with an oxidation wave of the closed-ring isomer was clearly observed at 0.82 V.

Efficient Synthesis, Photochromism and Fluorescence Properties of a Novel Diarylethene Bearing a Naphthalene

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.

Research on Photochromic Materials with Synthesis and Application of 1-(2-methyl-3-benzothienyl)-2-[2-methyl-(5-ethynyl)trimethylsilane-3-thienyl] Perfluorocyclopentene

A new unsymmetrical photochromic diarylethene compound, 1-(2-methyl-3-benzothienyl)-2-(2-methyl-(5-ethynyl) trimethylsilane-3-thienyl) perfluorocyclopentene (1o) has been synthesized, and its optoelectronic properties, such as photochromism and the fluorescence spectra of diarylethene 1o in hexane solution was investigated. The results showed that this compound exhibited reversible photochromism in solution. The maxima absorption of compound closed-ring isomer 1c are 538 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.

Efficient Synthesis, Photochromism and Fluorescence Properties of a Novel Diarylethene Bearing a Fluorene

A new symmetrical photochromic diarylethene, 1,2-bis-[2-methyl-5-(9,9-dibutyl-9H-fluorene) -3-thienyl] perfluorocyclopentene (1a), was synthesized and its optoelectronic properties, such as photochromism in solution and fluorescence were investigated. 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 new diarylethene also exhibited relatively strong fluorescence by photoirradiation in solution and the fluorescence intensity decreased along with the photochromism upon irradiation 297 nm light and its closed-ring isomer showed almost no fluorescence.

Carrier mobility of photochromic diarylethene amorphous films

Photochromic diarylethenes (DAEs) have gained attention as attractive current switching materials by light irradiation in the organic electronics field. We investigated the hole mobility of amorphous films consisting of three types of DAEs using a space-charge-limited current method and a better chemical structure to achieve high mobility. The hole mobility of open-ring (colorless) DAE having benzothiophene rings substituted with triphenylamine (TPA) as an aryl group was 2×104 times (2×10−6cm2/Vs) larger than that of DAE containing thiophene rings without TPA. When the DAE film was irradiated with ultraviolet (UV) light, the hole mobility decreased temporarily at 4% of closed-ring (colored) isomers and then increased to two-three times of the initial colorless state at 85% of the closed-ring isomers. The temporary decrease in the hole mobility originated in the hole trapping effect of the closed-ring molecules in a matrix consisting of open-ring isomers.