Renjie Wang

Multi-addressable molecular switches based on a new diarylethene salicylal Schiff base derivative

A novel photochromic diarylethene with a salicylidene Schiff base substituent has been synthesized and characterized. The diarylethene could be used as a multi-addressable fluorescence switch when triggered by light, protons and metal ions. As a result, two logic circuits were constructed with the unimolecular platform by using the fluorescence intensity at different wavelengths as outputs and appropriate combinational stimuli of UV/Vis light, TEA/TFA, and Al(III)/EDTA as inputs. Moreover, the diarylethene derivative was found to be highly selective towards Al(III) with significant color and fluorescence changes for potential applications as colorimetric fluorescent chemosensors.

Recent advances in diarylethene-based multi-responsive molecular switches

In the past decade, extensive functionalization of diarylethene backbones has enabled these molecules to respond not only to light but also to other external stimuli and extended their applications to biological and materials sciences. In this review, the recent progress on diarylethene-based multi-responsive molecular switches is summarized with emphasis on the modulation of their photophysical properties by multiple external stimuli, their structure–property–function relationship, and their underlying operating principles.

Highly emissive carbazole-based gold(I) complex with a long room-temperature phosphorescence lifetime and self-reversible mechanochromism characteristics

We report a highly emissive carbazole-based mononuclear gold(I) complex. Its solid shows a long room-temperature phosphorescence lifetime up to 29.91 ms. Furthermore, the luminogen exhibits self-reversible mechanochromic behavior.

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.

Effects of heteroaryl ring on the photochromism of asymmetrical diarylethenes containing a naphthalene group

Photochromic asymmetrical diarylethene derivatives 1o-4o bearing different benzo-five-membered heterocyclic rings were synthesized and characterized with single-crystal X-ray diffraction microscopy. The effects of heterocyclic ring on their properties including the photochromic behaviors in solution, solid state and crystalline phase were systematically investigated. The diarylethenes bearing benzothiophene or indole ring exhibited high cyclization quantum yields in solution, and evidently enhanced the fluorescent modulation efficiency in solid state, while those containing benzofuran or thiophene ring exhibited the opposite behaviors. In addition, indole ring red-shifted the absorption maximum, and notably enhanced the fatigue resistance of the diarylethene. These results indicate that heteroaryl ring played an important role in the photoisomerization of these diarylethenes, causing the heterocyclic effect.

Photochromism and Optical Recording of a Novel Unsymmetrical Diarylethene Based on Pyrrole Ring

A new unsymmetrical photochromic diarylethene compound, 1-[(2-methyl-5-(4-aldehydephenyl)-3-thienyl)]-2-(5-cyano-1, 5-dimethyl-4-pyrryl) perfluorocyclopentene (1o), was synthesized and its photochromic behavior, kinetics properties optical storage properties were investigated in detail both in solution and PMMA amorphous film. The results showed that this compound had good thermal stability and exhibited pronounced reversible photochromism, changing from colorless to mediumpurple in solution whereas to mediumslateblue in PMMA amorphous film after irradiation with 297 nm UV light, which may be attributed to giving a bathochromic shift in PMMA amorphous film. The colorless open form with fluorescence character could be regenerated by irradiation with visible light. The cyano group and its substituted position can availably modulate the optical and electrochemical behaviours of these diarylethene derivatives. In addition, polarization optical recording using this diarylethene as recording medium was performed successfully.

New Unsymmetrical Photochromic 1,2-Diaryleperfluorocyclopentenes Bearing a Naphthalene and Thiophene Moiety

A new photochromic diarylethene compound [1-(2-methyl-1-naphthyl), 2-(2-methyl-5-1,3-dioxolane-3-thienyl)]perfluorocyclopentene 1o was synthesized and its photochromic properties, kinetic properties and fluorescence switch were investigated in detail. Upon irradiated UV light it changes from colorless to orange and red in solution and PMMA amorphous film, respectively. The kinetic experiment suggested that the cyclization/cycloreversion process belong to zeroth and first order reactions, respectively. Finally, the diarylethene 1o was exhibited remarkable fluorescence switch properties along with the cyclization reactions.

Photochromic, kinetic and application for optical recording of a new diarylthene bearing pyrrole unit

A new photochromic diarylethene bearing thiophene and pyrrole unit 1-(2-cyano-1,5-dimethyl-4-pyrrole)-2-(2-butyl-5-(1,3-dioxolan-2-yl)thiophen-3-yl)perfluorocyclopentene (1o), was synthesized and its photochromic, kinetic and fluorescence properties were investigated in detail. This compound exhibited good photochromism, changing the color from colorless to blue upon irradiation with 297 nm UV light. The kinetic experiments suggested that the cyclization/cycloreversion process of the compound was determined to be the zeroth/first reaction in hexane, and the fluorescence intensity decreased along with the photochromism. Finally, using diarylethene 1c as recording medium, polarization optical recording was carried out successfully.

Synthesis, photochromic properties and application of a new diarylethene bearing a naphthalene and thiophene moiety

A new photochromic diarylethene compound [1-(2-methyl-1-naphthyl), 2-(2-methyl-5-(2-1,3-dioxolanephenyl)-3- thienyl)]perfluorocyclopentene 1o, and its photochromic properties, fluorescence switch and kinetic properties were investigated in detail. Diarylethene 1o changed the color from colorless to red when irraditated with 297 nm UV light, which the absorption maxima were observed at 503 nm in hexane solution. This new photochromic system also showed remarkable fluorescence switching in the solid state. Finally, using this diarylethene as recording medium, polarization optical recording was carried out successfully.

Synthesis, kinetics and application for optical recording of a new asymmetrical photochromic diarylethene

A novel photochromic diarylethene was synthesized and its photochromic, fluorescence and kinetics properties were investigated detail. This compound exhibited remakable photochromism, changing from colorless to blue after irradiation with UV light both in solution and in PMMA amorphous film. In hexane, the kinetic experiments showed that the cyclization /cycloreversion process of the compound was determined to be the zeroth/first reaction, respectively. Finally, The results demonstrated that the diarylethene compound had attractive properties for high density optical storage.