Isomeric Diarylethenes Research Articles

Novel colorimetric and fluorescent chemosensor for Hg2+/Sn2+ based on a photochromic diarylethene with a styrene-linked pyrido[2,3-b]pyrazine unit

In this work, two structurally novel isomeric diarylethene chemosensors based on a styrene-linked pyrido[2,3-b]pyrazine unit were synthesized by using Heck coupling reaction. Interestingly, the two reported chemosensors exhibited quick colorimetric sequential responses towards Hg2+ and then Sn2+. Furthermore, the fluorescence intensity of the diarylethene-mercury dyad 1O′ was significantly quenched due to the formation of a new complex 1O-Hg2+. 1O-Hg2+ could be used as a new platform for rapid detection of Sn2+, which involved a conspicuous fluorescence enhancement in the detection progress. Based on the fact that the fluorescence of luminogen 1O could be effectively adjusted by the stimulations of light and metal ions, an integrated combinational logic circuit was constructed with 365 nm UV light, Hg2+ and Sn2+ as input signals and the fluorescence intensity at 560 nm as output signals.

Sterically hindered diarylethenes with thienopyridine: Substituent position effect on photochromic properties

Diarylethenes (DAEs) have recently attracted great attention for their applications in light-responsive materials. As much efforts have been directed towards the elucidation of the structure-property relationship of DAE derivatives, improving photochromic performances through structure optimization is still worthy of study. Herein, three isomeric diarylethenes with thienopyridine units are designed for gaining insights into substituent position effect on photochromic performances. It is shown that the nitrogen atom in pyridine rings shows influence on the photochromic behaviors, such as photoreaction quantum yields, conversion ratios of target systems. Distinctively, thieno [3,2-b]pyridine-containing TP3 displays a novel solvent-dependent photochromic activity. And the photochromic reactivity of thieno [2,3-b]pyridine-containing TP1 can be specifically blocked by Cu2+, showing the gated photochromism. The diverse photochromic properties make the target systems promising candidates for the development of practical molecular devices with certain functions.

Substituent effect in the photochromism of two isomeric asymmetric diarylethenes having pyrrole and thiophene units

Two new asymmetric isomeric diarylethenes having pyrrole and thiophene units have been synthesized by one-pot reaction and characterized by single crystal X-ray diffraction analysis. The two prepared diarylethenes had disparate crystal structures, and they exhibited distinctly different photochromic behavior, both in solution and in the solid state. Their photochromism, fatigue resistance, and fluorescence were investigated systematically. The methyl group at the reactive carbon atom could significantly enhance the quantum yield of cyclization step and decrease the quantum yield of cycloreversion step, whereas a cyano group at the same position could notably suppress the photocyclization reaction and promote the photocycloreversion reaction. The results indicated that the substituent at the reactive carbon atom could readily modulate the optoelectronic and physical properties for these diarylethenes.

Photochromism of isomeric diarylethenes with a methylpyridine substituent

Two new isomeric photochromic diarylethenes with a methylpyridine unit have been synthesized and their structures have been determined by single-crystal X-ray diffraction analysis. Both diarylethenes exhibited photochromism in both solution and PMMA films. In the single crystalline phase, the two isomeric compounds displayed different photochromism based on their various molecular conformations. In addition, their fluorescent properties are also diverse due to the distinct substitution position of the methyl group on the terminal pyridine.

Photochromism of two novel protoncontrollable isomeric diarylethenes with a pyridine moiety: substituent effects on their properties

Two novel hybrid isomeric diarylethenes with pyridine and pyrrole units have been synthesized by a parallel reaction, and their structures were determined by single-crystal X-ray diffraction analysis. They exhibited distinctly different photochromic behavior and fluorescent properties upon photoirradiation due to the different substituent effects. In the crystalline phase, one is photoactive with an anti-parallel conformation, while the other is non-photoactive with a parallel conformation. Moreover, the closed-ring isomers showed different acidichromism in dichloromethane. The absorption maxima of one showed extraordinarily large red shifts of 120 nm, whereas that of the other exhibited extraordinarily large blue shifts of 194 nm.

Photochromism of novel isomeric diarylethenes with benzofuran and pyridine moieties

A new class of isomeric diarylethenes with benzofuran and pyridine moieties was synthesized to investigate the effects of the position of the nitrogen atom in pyridine moiety on their photochromism, acidichromism, and fluorescence. The six-membered pyridine moiety was connected directly to the central cyclopentene ring as an aryl moiety and participated in the photoisomerization reaction in both solution and solid media. These isomeric diarylethenes exhibited multi-addressable switching behavior by the stimulation of acid/base and light. Addition of trifluoroacetic acid to the solutions of these compounds produced the corresponding protonated derivatives. The protonated derivatives exhibited excellent photochromism and notable acidichromism, and the different nitrogen atom position resulted in distinguishable absorption spectra and color changes. The results revealed that the effects of the nitrogen atom position in pyridine moiety played a very important role during the photoisomerization process of these isomeric diarylethenes.

Synthesis and Properties of a New Unsymmetrical Diarylethene Bearing Benzothiophene and Thiophene Rings

A new unsymmetrical isomeric diarylethene was synthesized, namely1-[2-methyl-(5-(4-hydroxyl) phenyl) -3-thieny-2-(2-methyl-3-benzothiophene) perfluorocyclopentene (1o). Its photochromic reactivity both in solution and in PMMA film, photoconversion ratio at photostationary state, and fluorescence were investigated in detail. The compound displayed excellent photochromism both in solution and in PMMA film. The isomeric compound also functioned as a fluorescence switch and concentration dependence on the fluorescence spectrum in hexane.

Photochromism of new isomeric pyridine-containing diarylethenes with a benzofuran moiety

Three new isomeric pyridine-containing diarylethenes with a benzofuran moiety were synthesized, and the structures of two diarylethenes were determined by single X-ray diffraction analysis. Their properties such as photochromism, acidchromism, fluorescence, as well as electrochemical properties, were investigated in detailed. The diarylethenes exhibited multi-addressable switching behavior by light and acid/base stimuli in solution and functioned as a remarkable fluorescent switch in both solution and poly(methyl methacrylate) films. Among these isomeric derivatives, the example with the nitrogen atom at the ortho-position of pyridine showed the largest absorption maxima, molar absorption coefficients, and cyclization quantum yield. The nitrogen atom position in the terminal pyridine unit could efficiently modulate the optical and electrochemical properties of the diarylethenes with a benzofuran moiety. The results suggested that the benzofuran moiety and the nitrogen atom position in the terminal pyridine unit played a vital role during the process of photoisomerization reaction for these isomeric diarylethenes.

The effect of the fluorine atom position upon isomeric photochromic diarylethenes bearing a pyrrole unit

Abstract A new class of isomeric diarylethenes bearing a pyrrole moiety have been synthesized, and their properties including photochromism, fluorescence, and electrochemical properties have been discussed systematically. Each of the diarylethenes exhibited evident photochromism and functioned as a remarkable fluorescent switch in both solution and PMMA films. Their photoconversion ratios were larger than 90%, and the fluorescent modulation efficiencies were greater than 88% in the photostationary state. The absorption maxima, quantum yields of cyclization and cycloreversion, and band-gaps of the closed-ring isomers increased whereas the emission intensity and band-gaps of the open-ring isomers greatly decreased when the fluorine atom was attached at any of the three positions on the terminal benzene ring. 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 fluorine atom and its substituted position could availably modulate their optical and electrochemical behaviors.

Syntheses and photochromism of new isomeric diarylethenes bearing an indole moiety

Abstract Four new photochromic diarylethenes, each bearing an indole moiety, were synthesized and three of their structures were determined by single-crystal X-ray diffraction analysis. Under alternating irradiation with UV and visible light, the compounds showed favorable photochromism in hexane, PMMA films and the crystalline phase. The cyclization quantum yields gradually increased and the molar absorption coefficients of the closed-ring isomers decreased going from the ortho- to meta- to the para-position of the substitution. The absorption maxima showed little change when the methoxy group was attached at any of the three positions on the terminal benzene ring. Each of the compounds displayed high fluorescence efficiency and remarkable fatigue resistance in both solution and PMMA films by photoirradiation. Of particular note, their fluorescent modulation efficiency could be achieved ca. 90% in solid media. Cyclic voltammograms testified that the methoxy group and its substituted position could effectively modulate the electrochemical behaviors of these diarylethenes.

The effect of the formyl group position upon asymmetric isomeric diarylethenes bearing a naphthalene moiety

Three new isomeric asymmetric diarylethenes with a naphthyl moiety and a formyl group at the para, meta or ortho position of the terminal benzene ring were synthesized. Their photochromism, fluorescent-switch, and electrochemical properties were investigated. Among these diarylethenes, the one with a formyl group at the ortho position of benzene displayed the largest molar absorption coefficients and fluorescence quantum yield. The cyclization quantum yields of these compounds increased in the order of para < ortho < meta, whereas their cycloreversion quantum yields decreased in the order of meta > para > ortho. Additionally, all of these diarylethenes functioned as effective fluorescent switches in both solution and PMMA films. Cyclic voltammograms proved that the formyl group and its position could effectively modulate the electrochemical behaviors of these diarylethene derivatives.

Photochromism Material of New Unsymmetrical Isomeric Diarylethenes Bearing a Thiophene and Pyridine Unit

A new photochromic diarylethene compound, 1-(2,5-dimethyl-3-thiophene)-2-[5-(4-pyridine)-2-methyl-3-thienyl]perfluorocyclopentene(1a) was synthesized. its photochromic and fluorescent properties have been investigated in detail. The results of the research showed that it has shown good photochromic behavior and fluorescence switch in solution and PMMA film. Finally, photo-mode rewritable optical storage using 1b was performed. The images demonstrated that the compound can be used as optical storage material

Photochromism of new unsymmetrical isomeric diarylethenes bearing a pyridine group

A new class of unsymmetrical isomeric diarylethenes bearing a terminal pyridine group was synthesized and their structures were determined by single-crystal X-ray diffraction analysis. The effects of the nitrogen atom position in the pyridine group on their properties including photochromism, acidchromism, and fluorescence were investigated systematically. Among the three isomeric derivatives, the cyclization quantum yield and the absorption maxima of the ortho-substituted diarylethene were the biggest, while the fluorescence quantum yield of the para-substituted diarylethene was the biggest. Furthermore, the three isomeric diarylethenes exhibited multi-addressable switching behaviors by the stimulation of acid/base and light. Addition of trifluoroacetic acid to solutions of these diarylethenes produced the protonated derivatives, which also showed excellent photochromic behaviors, but only the para-substituted diarylethene exhibited a notable color change of solution from crimson to violet. The results revealed that the effects of the nitrogen atom position in the terminal pyridine group played a very important role during the process of photoisomerization for these isomeric diarylethene derivatives.

Synthesis, Photochromism and Fluorescence of a Novel Diarylethene Having Thiazole Unit

A new unsymmetrical isomeric diarylethene was synthesized, namely 1-(2,4-dimethyl-5-thiazolyl)-2-[2-methyl-5- (3-methoxyphenyl)-3-thienyl] perfluorocyclopentene (1o). Its photochromic reactivity both in solution and in PMMA film, photoconversion ratio at photostationary state, and fluorescence were investigated in detail. The compound displayed excellent photochromism both in solution and in PMMA film. The isomeric compound also functioned as a fluorescence switch and concentration dependence on the fluorescence spectrum in hexane.

Synthesis, Photochromism and Fluorescence of a Novel Diarylethene Having Thiazole Unit

A new unsymmetrical isomeric diarylethene was synthesized, namely 1-(2,4-dimethyl-5-thiazolyl)-2-[2-methyl-5- (3-methoxyphenyl)-3-thienyl] perfluorocyclopentene (1o). Its photochromic reactivity both in solution and in PMMA film, photoconversion ratio at photostationary state, and fluorescence were investigated in detail. The compound displayed excellent photochromism both in solution and in PMMA film. The isomeric compound also functioned as a fluorescence switch and concentration dependence on the fluorescence spectrum in hexane.

Synthesis, Properties and Application in Optical Memory of a Novel Photochromic Diarylethene Bearing an Anthracene Ring

In the present study, we designed a novel unsymmetrical isomeric diarylethene derivative bearing both thiophene and anthracene moieties. Its photochromic properties and fluorescence were investigated in detail. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence. The photochromic reaction kinetics indicated that the cyclization process of 1o belongs to the zeroth order reaction and the cycloreversion process belongs to the first order reaction. This new photochromic system also exhibited remarkable optical storage character.

Photochromism of a New Unsymmetrical Diarylethene Bearing both Thiazole and a Methoxyl Group

A new unsymmetrical isomeric diarylethene bearing an electron-donating methoxyl group atortho-positions of the terminal phenyl ring was synthesized, namely 1-(2,4-dimethyl-5-thiazolyl) -2-[2-methyl-5-(2-methoxyphenyl)-3-thienyl]perfluorocyclopentene (1o). The compound displayed excellent photochromism both in solution and in PMMA film. The isomeric compound also functioned as a fluorescence switch by photoirradiation in solution. In addition, cyclic voltammetry tests showed that the electron-donating methoxyl group at the terminal benzene ring had a significant effect on the electrochemical properties of the isomeric diarylethene.

Synthesis and the effect of substituent position upon unsymmetrical isomeric diarylethenes bearing a pyrrole unit

Four unsymmetrical diarylethenes bearing a pyrrole moiety were synthesized, and the structures of two isomeric compounds were determined by single-crystal X-ray diffraction analysis. The properties of these compounds, including photochromism, fluorescence and electrochemical properties of these diarylethenes were also investigated systematically. Each of the four diarylethene derivatives exhibited good photochromism and functioned as an effective fluorescent photoswitch both in solution and in PMMA films. The absorption maxima, the quantum yields of cyclization and cycloreversion, and the fluorescence quantum yields of the open-ring isomers increased whereas the emission peaks decreased evidently when the methoxy group was attached at any of the three positions on the terminal benzene ring. Compared with the analogous diarylethenes bearing a pyrazole moiety, the introduction of the pyrrole moiety could increase the absorption maxima and decrease the cycloreversion quantum yields significantly. Cyclic voltammograms testified that methoxy group and its substituted position could effectively modulate the electrochemical behaviours of these diarylethene derivatives.

The photochromism of unsymmetrical diarylethene isomers with an electron-withdrawing cyano substituent

Three unsymmetrical isomeric diarylethenes bearing an electron-withdrawing cyano group were synthesized and their structures determined using single-crystal X-ray diffraction analysis. Each of the compounds displayed excellent photochromism in solution, in PMMA film, as well as in the crystalline phase. The isomeric compounds also functioned as a fluorescence switch in PMMA films. The cyclization quantum yield and the absorption maxima of both the ring-opened and ring-closed isomers increased in the order: ortho- < meta- < para-substitution of the cyano group. Compared with the unsubstituted parent compound, the cycloreversion quantum yield decreased whereas the molar absorption coefficient of the ring-opened and the ring-closed isomers increased significantly when the cyano group was attached at any of the three positions on the terminal benzene ring. Cyclic voltammetry studies indicated that the position of cyano substitution had a marked effect on the electrochemical behaviours of these isomeric diarylethenes.

Photochromism of new unsymmetrical isomeric diarylethenes bearing a methoxyl group

Three new unsymmetrical isomeric diarylethenes having a methoxyl substituent at ortho-, meta-, and para-position of the terminal benzene ring, namely 1-(2,5-dimethyl-3-thienyl)-2-[2-methyl-5-(2-methoxylphenyl)-3-thienyl]perfluorocyclopentene (1o), 1-(2,5-dimethyl-3-thienyl)-2-[2-methyl-5-(3-methoxylphenyl)-3-thienyl]perfluorocyclopentene (2o), and 1-(2,5-dimethyl-3- thienyl)-2-[2-methyl-5-(4-methoxylphenyl)-3-thienyl]perfluorocyclopentene (3o), have been synthesized. The substituent position effect of methoxyl group on their properties, including photochromism and fluorescence both in hexane solution and in PMMA film, and their electrochemical properties, were investigated in detail. These diarylethenes showed good photochromism both in solution and in PMMA film. For the same photochromic diarylethene backbone, the electron- donating methoxyl substituent can effectively depress the cyclization quantum yields and increase the cycloreversion quantum yields compared to those of diarylethenes bearing chlorine atoms reported previously. Diarylethenes 1o–3o showed clear fluorescent switches by photoirradiation both in hexane and in PMMA film. In addition, cyclic voltammetry tests showed that the electron-donating methoxyl group at different position on the terminal benzene ring had a significant effect on the electrochemical properties of these isomeric diarylethenes. Copyright © 2009 John Wiley & Sons, Ltd.