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In this work, a rhodamine derivative was developed as a colorimetric and ratiometric fluorescent probe for Hg

A novel turn-on fluorescent sensor for Al

Supplemental material, Supplementary_Material for Structure and photochromic properties of a novel diarylethene containing a 9-fluorenone hydrazone Schiff base moiety by Yuexia Zhuge, Chunhong Zheng, Guanming Liao and Shouzhi Pu in Journal of Chemical Research

A new photochromic diarylethene derivative with a 4-methylphenol unit has been designed and synthesized. It displayed distinct photochromism and fluorescent ''turn on'' features to Mg

In this work, a colorimetric and ratiometric fluorescent sensor based on a coumarin-rhodamine B hybrid for the sequential recognition of Cu

The sensing of phosphate anion (PO43−) is an important subject for human health and environmental monitoring. Herein, a unique ratiometric fluorescent nanoprobe based on postsynthetic modification of metal-organic frameworks (MOF) UiO-66-(COOH)2 with Eu3+ and Ce3+ ions toward PO43− was proposed (designated as Eu/Ce/Uio-66-(COOH)2). The Eu/Ce/Uio-66-(COOH)2 nanoprobe exhibits three emission peaks at 377 nm, 509 nm, and 621 nm with the single excitation wavelength at 250 nm, respectively. The strong coordinating interaction between Ce3+ and O atoms in the PO43− group can result in the fluorescence quenching at 377 nm, while the fluorescence of 621 nm almost remains unchanged. Such a useful phenomenon is exploited for the construction of a ratiometric fluorescence platform for the detection of PO43−. The assay exhibited a good linear response in the 0.3–20 μM concentration range with the detection limit of 0.247 μM. In addition, this ratiometric fluorescent sensing method not only can be applied to read out PO43− concentration in real water samples, but also shows higher sensitivity, easier preparation and sensing procedures than other detection strategies.

A series of asymmetric 9, 10-dithiopheneanthrylene derivatives (DTAs) with various substituent groups and large Stokes shifts (>80 nm) have been synthesized and characterized. All of them displayed aggregation-induced emission enhancement (AIEE) behaviors expect for DTA-M, which fluorescence was gradually enhanced in low water fraction (50%), but dramatically quenched with the increase of water fraction to 90% due to the twisted intramolecular charge transfer (TICT) effect. The size of particles in aggregates were studied by using a scanning electron microscope, indicating the formation of morphological diversity nanoparticles due to the various substituents on 2-position of lateral thiophene ring. Furthermore, all of them exhibited reversible mechanofluorochromic and vapochromic luminescence behaviors, especially compound DTA-M, which showed high color contrast mechanofluorochromism between yellow and red color. In addition to the AIEE and mechanofluorochromic properties, HeLa cells fluorescence imaging experiments proved that these DTAs are capable to achieving bioimaging.

A new europium(III) complex Eu(tta)3L1 (1a) (L1 = (2-(3,5-dimethoxyphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline), tta = 2-thenoyltrifluoroacetone) has been prepared and synthesized. The structure of complex was completely determined by several different analytical techniques including single-crystal X-ray diffraction, 1H and 13C NMR. The crystal structure of the complex 1a belonged to monoclinic system with the space group P21/n. Its fluorescent properties were systematically studied in details by adding different metal ions in deionized water. Upon addition of Sn2+, its fluorescence intensity was strengthened and centered at 460 nm. And when Cu2+ was added, its fluorescence emission intensity was quenched quickly. The LODs for Sn2+ and Cu2+ were calculated to be 4.52 × 10−7 mol L−1 and 1.11 × 10−7 mol L−1, respectively. Furthermore, this sensor was successfully employed to monitor Sn2+ and Cu2+ in practical samples.

A diarylethene derivative has been synthesized by attaching a photochromic core to a pyrazine moiety through an aroylhydrazone linker. The compound showed weak excited state intramolecular proton transfer (ESIPT) based fluorescence in a series of polar solvents such as CH3CN, THF, DMSO, CH3CH2OH, CH3OH and their binary mixtures with water. However, when the water fraction in solutions was above 70%, a strong orange ESIPT emission at ~ 580 nm was found, which originated molecules aggregate and ESIPT. The active ESIPT process remains in the solid state, which exhibited orange fluorescence under 365 nm light illumination. The diarylethene derivative has been found to show fluorescence ‘‘turn-on’’ sensing Al3+ in CH3CN with the detection limit of 16.6 nM. Al3+ enhanced the fluorescence with 30 nm blue shifts and the fluorescence can be ON and OFF through interaction with Al3+ and EDTA. Moreover, the Al3+ in several water samples was detected using the sensor with high accuracy.

A near-infrared probe Ru-1 with a phenothiazine derivative moiety as a responsive unit was designed to sensitively and selectively recognize HOCl in pure PBS solution. Upon addition of HOCl to a PBS solution of Ru-1, S-atom of the phenothiazine unit oxidized to sulfoxide, accompanied with a marked fluorescence enhancement about 60 fold at 635 nm. Probe Ru-1 displayed excellent water-solubility (PBS solution), low detection limit (4.4 nM), long fluorescence lifetime (354.36 ns) and large Stokes shift (175 nm). The experiments of its quantitative detection HOCl in water samples implied the probe Ru-1 possessed potential application in the environment.

Two diarylethenes containing the hybrid structures of benzothiophene and pyrrole backbone were synthesized and their structures and properties including photochromism, fatigue resistance, and fluorescence were systematically investigated. Both of them exhibit good photochromisms and can function as fluorescence switches in both solution and solid state upon the irradiations of UV/vis lights. Compared with that bearing cyano group (1O), the carboxamide group containing diarylethene (2O) exhibits a higher molar absorption coefficient in solution, and its maximum absorption in solid state red-shifts by 30 nm, as compared with that in solution. In addition, the application potentials of 2O in bioimaging are demonstrated with excellent performances under physiological conditions.

A diarylethene derivative with an aroylhydrazone unit was designed and synthesized as a colorimetric and fluorimetric dual responsive sensor for Cu2+ with high selectivity and rapid response. Connecting 7-diethylamino-3-hydrazide-coumarin moiety and 2-pyridyl-containg diarylethene provided an intramolecular charge transfer (ICT) system with affluent binding site (N^N^O), which was developed for the selective and sensitive detection of Cu2+ by dual colorimetric and fluorimetric responses. A clear Cu2+-induced ratiometric colorimetric sensor with color change from light yellow to orange red and on-off fluorescence with fluorescence color change from bright cyan to deep teal was constructed. At the same time, colorimetric and fluorimetric responses to Cu2+ were both achieved at the photostationary state. Based on the obvious color change, the sensor was used for the fabrication of test strips that can be used as the standard cards for detecting Cu2+. This study is expected to facilitate and broaden the application of diarylethene derivative in tracing Cu2+ in future work.

Three fluorene-based tetraphenylethene derivatives with alkyl chains of different lengths were synthesized and characterized. All of these fluorescent dyes showed excellent aggregation-induced emission characteristics. Furthermore, these compounds also displayed tunable solid-state fluorescence involving various colors of blue-green, green and blue. More interestingly, their different mechanoresponsive behaviors could be effectively adjusted by minor alkyl modifications.

A novel diarylethene derivative chemosensor DTP-o connected to Schiff base unit for fluorescent detection of Zn2+ and relay-detection of HSO4−/H2PO4− was designed and synthesized successfully. DTP-o displayed excellent photochromism and fluorometric sensing toward Zn2+ to form DTP-o-Zn2+ complex in acetonitrile with the detection limit of 5.62 × 10−7 M. And the form of DTP-o combined with Zn2+ could further be verified by Job's plot titrations and mass spectrometry analysis. Furthermore, the complex of DTP-o-Zn2+ showed an excellent characteristic of fluorescent relay-response toward HSO4− and H2PO4− with high sensitivity and selectivity. The detection limits for HSO4− and H2PO4− were as low as 3.04 × 10−8 M and 3.41 × 10−8 M, respectively. Moreover, the sensor DTP-o could also be applied to detect Zn2+ on practical samples and test strips with high accuracy.

A new iridium(Ⅲ) complex-based near-infrared ‘turn-on’ fluorescent probe Ir-DNBS was synthesized for fast (9 min), highly selective and sensitive (LOD: 62.5 nM) thiophenol detection. Photophysical and spectral characterization (NMR, HRMS) results demonstrated that the recognization mechanism of probe for thiophenol was based on thiolate-mediated nucleophilic elimination reaction (SNAr). Upon addition with thiophenol to PBS/DCM/DMSO solution (pH = 7.4) of probe Ir-DNBS, obvious orange red fluorescence with maximum emission wavelength at 620 nm was observed with a large Stokes shift (200 nm) and long lifetime (135 ns). The practical utility of probe Ir-DNBS was also investigated by thiophenol detection in real water samples and human serum.

A novel photochromic diarylethene derivative containing a diaminomaleonitrile unit (1O) was synthesized and its colorimetric and fluorescent turn-on sensing of Cu2+ in acetonitrile solution was demonstrated. Both of its open- and closed-loop isomers (1O and 1C) were highly selective for Cu2+ with obvious absorption and color transforms. Moreover, the addition of Cu2+ enhanced the fluorescence of 1O up to 174-fold with the concomitant color change from colorless to blue. The limit of detections (LODs) for Cu2+ was determined to be 1.76 × 10−8 mol L−1. The stoichiometry of 1: 1 between the probe 1O and Cu2+ was measured in Job’s plot and ESI-MS. Most remarkably, the probe 1O could be used to detect Cu2+ in test strip.

A novel diarylethene derivative 1O with the unit of N-(2-(hydrazinecarbonyl)phenyl)benzamide was designed and synthesized successfully. The sensor showed excellent photochromism and specific fluorescent detection toward aluminum ion with rarely interfering. The emission intensity could increase nearly by 100 folds with aluminum ion and the color changed from dark to Aqua green. The low limit of detection (LOD) of 1O was determined as 3.26 × 10-8 mol L-1. Additionally, the sensor could be used in logic circuit and aluminum ion detection in untreated water.

Four newly synthesized tetraphenylethene or triphenylethylene-modified fluorescent dyes were reported. All synthesized luminophores displayed typical aggregation-induced emission effects, with bright and varying aggregative-state emission involving multiple fluorescence colors containing yellow, orange, green, and yellow-green. In addition, these luminogens also showed different fluorescence in the solid state. Meanwhile, their solid-state fluorescence could be effectively switched by mechanical grinding and solvent fuming except for luminogen 4. More specifically, luminogen 1 exhibited a weak mechanofluorochromic response with a color change from yellow to yellowish brown, whereas luminogen 4 displayed negligible mechanofluorochromism behavior. In stark contrast to luminogens 1 and 4, luminogens 2 and 3 in the solid state were characterized by reversible high-contrast mechanochromic phenomena involving distinct fluorescent color changes from green to orange and from blue to yellow, respectively. These contrasting fluorescence changes were due to the morphological conversion from stable crystalline state to metastable amorphous state.

An aggregation-induced emission enhancement (AIEE)-active fluorescent sensor has been successfully designed and synthesized, combining the AIE effect of tetraphenylethylene (TPE) with the cyanide acceptor of phenanthro[9,10-d]imidazole. The sensor exhibits not only the property of AIEE in DCM/n-hexane or THF/H2O, but also the phenomenon of mechanofluorochromic (MFC). It displays large Stokes shift (107 nm) due to the intramolecular charge transfer (ICT) process. The cation of CN− boosts the ICT process to make the greater Stokes shift (184 nm) with the fluorescent color vary from blue-green to sodium-yellow and visually turning from light yellow to dark yellow in the naked eyes. The results of Job's plot, ESI-MS and the DFT calculations provide the stoichiometric ratio and electronic properties of the sensor. Furthermore, the sensor could be applied to qualitative and quantitative detection of CN− on test paper strips.

Three carbazole-containing isocyano-bridged mononuclear gold(I) complexes with different substituents are reported. The complexes display an aggregate luminescence change effect involving a color change from blue to yellow-green. In the solid state, luminogens 1–3 exhibit varying room-temperature phosphorescence involving blue, light yellow, and yellow emissions. In contrast, at 77 K, the gold(I) phosphors 1–3 display stronger (blue-green or yellow-green depending on the phosphor) phosphorescence with longer luminescence lifetimes. In addition, the solid-state phosphorescence of 1–3 is adjusted by moderate mechanical stimulus. More specifically, phosphor 1 shows reversible high-contrast mechanoluminochromic behavior involving interconversion between blue and yellow-green luminescence and phosphor 2 shows reversible mechanoluminochromism phenomenon involving luminescent interconversion between light yellow and light green. In contrast, solid-state phosphor 3 displays an irreversible mechanoluminochromism phenomenon—a strong yellow-green luminescence is observed after grinding. Subsequent treatment with dichloromethane vapor results in a blue-emitting sample.

A red-emitting cyclometalated Ir(III) complex-based phosphorescent probe 1 was designed and synthesized to selectively and sensitively detect thiophenol in 90% DMSO/PBS (0.01 M, pH = 7.4) solution with a low detection limited (LOD = 8.68 × 10−7 mol L−1). For probe 1, cyclometalated [Ir(ppy)2Phen]+ moiety acted as phosphor, 2,4-dinitrobenzenesulfonyl (DNBS) group was regarded as recognition site and phosphorescent quencher, and polyether (1-ethoxy-2-(2-methoxyethoxy)ethane) units in the C^N ligands was introduced to improve the water solubility of complex. Due to strong electro-withdrawing DNBS moiety, probe 1 exhibited very week phosphorescence at 600 nm. Upon addition with thiophenol to probe 1 and DNBS moiety left due to the cleavage of sulfonamide bond though nucleophilic elimination reaction, an obvious phosphorescence at 600 nm belong to complex 2 could be observed and the solution displayed red phosphorescent color. Meanwhile, the probe possessed a large Stokes shift (180 nm) and a relatively larger phosphorescence lifetime (τ = 5.265 μs). At the same time, the probe could be used for quantitative detection of thiophenol in actual water samples with high recovery, and detect thiophenol in human serum (100-fold dilution by PBS).

A diarylethene bearing a triazole-linked rhodamine B unit was synthesized. Its fluorescent emission was significantly enhanced in the presence of protons or Cu2+ due to transformation from the pirocyclic form to open-ring form. The fluorescence was quenched sequentially upon irradiation with 297 nm light based on the intramolecular fluorescence resonance energy transfer mechanism. In an acetonitrile: water binary solvent (1: 1 v/v), the compound showed significant fluorescent enhancement for Cu2+ compared with a wide range of tested metal ions with a fast response and a limit of detection of 2.86 × 10-8 mol L-1 . Using Cu2+ and UV light as the chemical inputs, and fluorescence intensity at 597 nm as the output, a logic gate was developed at the molecular level. Moreover, the compound can be used with a high accuracy to detect Cu2+ in a natural water sample.

A new diarylethene derivative containing a quinoline–benzimidazole conjugated system had been designed, synthesized, and utilized as a fluorescent probe. The probe could effectively respond to the stimulation of light and metal ions. It exhibited high selectivity and sensitivity toward Cd2+ and Zn2+ with different binding modes, approved by the Job’s plot, 1H NMR, and HRMS experiments. A combinational logic circuit was constructed by using the UV light, visible light, and metal ions (Cd2+/Zn2+) as three inputs and fluorescence intensity as output.

A novel Br-substituted diarylethene was synthesized, and its structure has been determined by single-crystal X-ray diffraction analysis. Its photochemical property in solution, a PMMA film, and single crystalline phase was studied. In solution, the absorption maximum of its closed-ring isomer shifted dramatically to shorter wavelengths with notable color change from violet to yellow upon the stimulation of trifluoroacetic acid. Moreover, the acidichromism showed obviously solvent-dependence. With enhancement of solvent polarity, the protonation-induced absorption maxima (Δλ max ) and the response time became longer.

A novel diarylethene derivative 1O with fluorescein-quinoline unit was designed and synthesized successfully. Under the stimulation of light and chemical, the diarylethene molecule exhibited multi-responsive photoswitchable properties. Moreover, the compound was a potential ‘naked eye’ chemosensor with significant color and fluorescence changes in the recognition of Cd 2+ in tetrahydrofuran (THF). When the fluorescein spirolactam ring-opened form was triggered with Cd 2+ , an obvious red shift from 459 nm to 560 nm (101 nm) was observed in complex 1O ′, and the emission intensity was enhanced by 8 fold with a concomitant fluorescence color change from dark to bright yellow. Significantly fluorescent quenching was observed in ring-closed isomer 1C ′ due to the FRET (fluorescence resonance energy transfer) processes between fluorescein moiety and the ring-closed diarylethene moiety. The interference from other effective metal ions, particularly Zn 2+ , had not been observed. Finally, a molecular logic circuit was constructed with both light and chemical stimuli as inputs and fluorescence intensity at 560 nm as output.

A novel diarylethene derivative with two rhodamine B units has been synthesized successfully. The diarylethene could be effectively controlled by the stimulation of light, proton, and metal ions. The fluorescence intensity of the diarylethene was enhanced upon addition of TFA, Al 3+ , Cr 3+ , and Fe 3+ , which was assigned to the blocked FRET process by the protonation of the rhodamine or complexation with Al 3+ , Cr 3+ , and Fe 3+ . The results indicated that the diarylethene could act as a multi-addressable fluorescence switch with the light, proton, and metal ions stimulus. Moreover, two logic circuits were constructed with the fluorescence intensity as the output signal responding to the light and chemical species as the inputs.

In this work, two-color pump-probe measurements, were performed to study the effect of the structural configuration on the excited state decay dynamics of dithienylethene photochromism systems under ring-closure state. Obvious different transient absorption dynamics were observed under parallel and perpendicular polarization configurations. The rising part of the perpendicular component probed at wavelength of 800 nm was clearly delayed compared with the parallel component, indicating some overlap between pure excited state decay dynamic and some processes of other mechanism.

A new photochromic diarylethene with an acetohydrazino-linked 8-methoxyquinoline unit was synthesized and its structure was determined by single crystal X-ray diffraction analysis. The diarylethene exhibited favorable photochromism and fluorescent switching properties by photoirradiation. Especially, it can sever as a highly selective fluorescent sensor for recognition of Zn2+ and F− ions, respectively. When triggered by Zn2+, its fluorescence intensity was enhanced evidently and its emission peak was red-shifted from 418 nm to 469 nm with a concomitant color change from dark to bright blue. On the other hand, F− can induce its emission peak to redshift by 129 nm with an emission intensity of 13-fold at the plateau under the same conditions.

A new diarylethene derivative with a coumarin unit was synthesized. Its multi-functional fluorescent switching behaviors were investigated by the stimulation of UV/vis light, Zn 2+ /EDTA, and F − . The diarylethene was highly selective toward Zn 2+ and F − with different fluorescence colors and binding modes. Upon addition of Zn 2+ , its emission peak was blue-shifted by 32 nm and emission intensity was enhanced by 57 fold, due to the formation of a 1:1 metal/ligand complex, accompanied by a fluorescence color change from dull red to green. Moreover, the diarylethene was also selectivity to F − with the fluorescence color change from dull red to yellow. The dramatic fluorescence color change made the naked eye detection of Zn 2+ and F − possible.

A new diarylethene containing a pyridinepiperazine-linked hydroxyquinoline group was synthesized. Its multi-controllable switching behaviors induced by light and chemical stimuli were investigated. The diarylethene could be used as a fluorescent probe for the detection of Cd2+ with high selectivity. When triggered by Cd2+, enhanced fluorescence intensity accompanied with color change from light blue to bright blue was observed. In addition, the diarylethene exhibited notable fluorescence enhancement upon the addition of TFA into the solution. Moreover, its fluorescence behaviors in response to light and Cd2+ were applied for the construction of a molecular logic circuit with four inputs and one output.

A new diarylethene with an antipyrine unit was synthesized and its multi-controllable photochromic and fluorescent behaviors induced by stimulation of light, acid/base, and metal ions were investigated in detail. The diarylethene showed favorable photochromism by photoirradiation, but its photochromism was entirely inhibited by the stimulation of tetrabutylammonium hydroxide. Its fluorescence showed sequence-dependent responses through efficient interaction of salicylaldehyde-linked antipyrine unit with light, base, and specific metal ions. Its fluorescence intensity was enhanced sharply with a notable color change from bright orange to bright yellow as a naked-eye fluorescent chemosensor for recognition of Al 3+ with high selectivity. Finally, two logic circuits were constructed on the basis of the multi-responsive photochromic and fluorescent behaviors of the unimolecular platform.

A new asymmetrical photochromic diarylethene with a 2-(2′-hydroxyphenyl)benzothiazole unit has been synthesized. It underwent reversible cyclization and cycloreversion reactions upon alternating irradiation with lower energy UV (297 nm, 25 μW/cm2) and visible light, while it could induce intramolecular proton transfer reaction upon irradiation with higher energy UV light (254 nm, 92 μW/cm2) with distinct color change. The absorption maximum of the closed-ring isomer was redshifted from 539 nm to 660 nm and the color changed from purple to cyan when the diarylethene was stimulated with base. Furthermore, addition of acid enhanced its fluorescence intensity by 5.5 fold and the emission peak was blueshifted from 596 nm to 570 nm with a concomitant color change from light orange to bright green, while base could efficiently quench its fluorescence intensity. Finally, the diarylethene was highly selective towards Cu2+ with significant absorption and fluorescence changes, which makes the ‘naked-eye’ detection of Cu2+ possible.

A novel diarylethene derivative with a Rhodamine B unit was synthesized successfully. It displayed favorable photochromism upon irradiation with UV/vis light. Upon addition of Hg(2+), distinct changes were observed in the absorption and fluorescent spectra due to the formation of a 1:1 ligand/metal complex. As a result, the diarylethene can serve as a fluorescence / colorimetric dual-channel sensor for highly selective and sensitive recognition of Hg(2+) in acetonitrile. Moreover, a complicated logic circuit was constructed with the combinational stimuli of UV/vis, Hg(2+)/ EDTA as input signals and the fluorescence intensity at 605 nm as output signal.

An asymmetrical diarylethene (1O) with a bi-8-carboxamidoquinoline unit was synthesized. Its photochromic and fluorescence performances on stimulation with both light and metal ions showed that the diarylethene could serve as a highly selective ratiometric fluorescent chemosensor to detect Zn2+ ions based on internal charge transfer and chelation-enhanced fluorescence processes. The diarylethene could selectively discriminate Zn2+ from Cd2+ in acetonitrile. Furthermore, Job's plots based on fluorescence titration and electrospray ionization mass spectrometry analysis showed 1 : 1 binding stoichiometry between 1O and Zn2+ . The binding constant of 1O with Zn2+ , estimated using the Benesi-Hildebrand method, and the limit of detection were 3.37 × 105 M-1 and 4.6 × 10-8 mol/L, respectively. Additionally, the light and metal-responsive fluorescence behavior of 1O was used successfully to construct a molecular logic circuit with four inputs and one output. Copyright © 2016 John Wiley & Sons, Ltd.

A novel photochromic diarylethene has been synthesized using dithieno-benzo-imidazole as a functional group and perfluorodiarylethene as photon-controlled unit via a benzene linkage. The diarylethene could be used as a multi-addressable fluorescence switch upon triggering by acid/base, light, and Al 3+ in acetonitrile. When stimulated by base, the absorption maximum of its closed-ring isomer was red-shifted from 560 nm to 594 nm with an evident color change from purple to blue. When induced by acid, the emission intensity of its open-ring isomer was enhanced by 109 fold with a notable fluorescence color change from dark to bright cyan. Moreover, its fluorescence intensity was dramatically increased when triggered by Al 3+ and its emission peak was red-shifted from 460 nm to 476 nm due to the formation of a 1:2 metal/ligand complex. In addition, its light and metal-responsive fluorescence behavior was applied to the construction of a molecular logic circuit with three inputs and one output.

Two novel perfluorodiarylethenes which contains a 2-methylbenzo[b]furane and a modified pyridine moiety were synthesized. Such structure may induce F⋯N or S⋯N heteroatom contact which was newly observed. Experiments results showed that the photocyclization quantum yield exhibited a strong correlation with the two weak intramolecular interactions, which behaved solvent independency. Moreover, both novel pyridine-perfluorodiarylethenes exhibited an obvious acidichromism, and the absorption maxima of their closed-ring isomers showed a prominent bathochromic shift to the near-infrared region.

A highly selective and sensitive ratiometric fluorescent sensor for Zn2+ was constructed by using a new diarylethene with a benzyl-linked 8-aminoquinoline-2-aminomethylpyridine unit. Its fluorescence could be reversibly modulated by photoirradiation and metal ions. Stimulated by Zn2+, its emission peak was red-shifted from 421 nm to 515 nm and the emission intensity was enhanced by 7-fold with a concomitant fluorescence color change from dark to bright green. Especially, the diarylethene can effectively avoid interference of Cd2+. Consequently, the diarylethene could serve as a naked-eye fluorescence chemosensor for detection of Zn2+ with high selectivity. The binding stoichiometry between the diarylethene and Zn2+ was 1:1 and the detection limit was 6.6 × 10−8 mol L−1. In addition, a logic circuit was designed on the basis of the unimolecular platform by using the fluorescence intensity at 515 nm as an output and the combinational stimuli of UV/vis and Zn2+/EDTA as inputs.

A new fluorescent chemosensor for recognition of Cd 2+ has been constructed by attaching methylquinoline to a photochromic diarylethene skeleton as photoswitching trigger via a pyridyl linkage. Its multifunctional fluorescent switching characteristics induced by light, Cd 2+ , and proton were systematically investigated. The diarylethene could serve as a fluorescence chemosensor for recognition of Cd 2+ with high selectivity, avoiding the interference of Zn 2+ . In addition, the fluorescence of the diarylethene could be effectively modulated by light and proton. Consequently, two logic circuits were constructed by using the fluorescence intensity as output signals with the combinational stimuli of light and chemical species as inputs.

A new photochromic diarylethene with a triazole-linked fluorescein unit has been synthesized by click chemistry and its multi-controllable fluorescence characteristics have been systematically investigated by the stimulation of light, base/acid, and metal ions. The absorption and fluorescence behaviors of the diarylethene displayed sequence-dependent responses via efficient interactions of the fluorescein unit with triethylamine/trifluoroacetic acid and UV/Vis light. As a result, a logic gate was constructed by using combinational stimuli of UV, Vis, and base as three inputs and the fluorescence intensity at 541 nm as the output. Furthermore, the diarylethene could serve as a highly selective ‘turn-on’ fluorescence chemosensor for the recognition of Cu 2+ . When the diarylethene was treated with Cu 2+ and AscH − , the fluorescence intensity at 541 nm was dramatically enhanced by ten fold with remarkable fluorescence change from dark to bright green due to Fenton reaction-assisted fluorescence signal amplification.

A new fluorescent chemosensor for the sequential recognition of Fe3+ and cysteine has been constructed based on photochromic diarylethene. It exhibits sequential recognition of Fe3+ and cysteine via an “on–off–on” molecular switch. The title compound can selectively and sensitively recognize Fe3+ in methanol, causing quenching of the fluorescence. Then, the formed complex was found to be a fluorescent chemosensor for cysteine with an increase in the fluorescence intensity. A detection limit as low as 4.09 × 10−8 mol L−1 for Fe3+ and 2.89 × 10−8 mol L−1 for cysteine was obtained. Moreover, a two input INHIBIT logic gate was fabricated by using Fe3+ and cysteine as inputs and taking I439 as the output.

A novel diarylethene derivative with a 3-hydroxy-2-naphthohydrazide unit was successfully synthesized. It displayed favorable photochromism upon irradiation with UV/vis lights. The deprotonated derivative of the diarylethene, due to the addition of triethylamine into its solution, also showed excellent photochromism with a distinguishable color change. The deprotonated example could recover its original state using trifluoroacetic acid. Furthermore, the diarylethene was highly selective toward Al3+ with an obvious fluorescent color change from dark to green in acetonitrile. Finally, two logic circuits were constructed on the basis of the unimolecular platform with multi-responsive photochromism and fluorescent switching properties.

A new photochromic diarylethene bearing an 8-aminoquinoline unit was designed and synthesized. Its multi-addressable behaviors induced by light and chemical stimuli were investigated. It is highly sensitive towards Mg2+ and Ca2+ with fluorescence emission and color changes. Moreover, a combinational logic circuit was constructed with four inputs of the combinational stimuli of light and chemical species, and one output of fluorescence intensity.

The recognition and sensing of ions have attracted growing attention because of the important role played by ions in biological, industrial and environmental processes. However, many sensors can only detect a single ion. We report here a rhodamine-based sensor with functions of dual ion detection. It displays a quick colorimetric and fluorometric sensing ability on 1 : 1 binding to Hg2+, with a change of color of solution (colorless to pink) and fluorescence color (dark to orange) due to Hg2+-induced opening of the spirolactam ring in the rhodamine structure. The detection limits were found to be 32 nM and 44 nM by absorption and fluorescence methods, respectively. More importantly, the resulting complex 1–Hg2+ can be used as a reversible fluorescence sensor for I−. With the addition of I−, the fluorescence intensity was quenched because Hg2+ in the complex was grabbed by I− attributed to the stronger binding force between Hg2+ and I−. Based on the “OFF–ON–OFF” behavior, a molecular device with “INHIBIT” logic gate function was constructed.

A novel photochromic diarylethene with a naphthalofuran group was designed and synthesized, and its structure was determined by single-crystal X-ray diffraction analysis. Its multi-addressable properties were investigated using light stimulation and chemical agents. The diarylethene was highly sensitive to Al3+ with obvious emission intensity and fluorescent color changes, indicating that it could act as a naked-eye fluorescent sensor for Al3+. Furthermore, a combinational logic circuit was constructed with the unimolecular platform using four input signals (In1: UV light; In2: visible light; In3: Al3+; In4: DETA) and one output signal (fluorescence intensity at 536 nm).

A new photochromic diarylethene based sensor with a salicylhydrazide Schiff base unit has been synthesized and its photochromic and fluorescent behaviors have been systematically investigated by the stimulation of light and metal ions in methanol. It displayed a dual-mode with a “turn on” fluorescence response and color changes upon addition of Al3+ or Zn2+. The LODs for Al3+ and Zn2+ were determined to be 8.31 × 10−8 mol L−1 and 3.33 × 10−7 mol L−1, respectively. A logic circuit was designed by using the fluorescence intensity as an output and the combinational stimuli of UV/vis and Al3+/EDTA as inputs. Furthermore, the living cell imaging results demonstrated its value of practical applications in biological systems.

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.

A novel cyclometalated iridium(III) complex-based luminescent probe Ir-1 for HCO3− and CO32− detection has been synthesized and characterized. The probe displayed no fluorescence around 600 nm, while a more than 10-fold enhancement in fluorescence emission intensity was observed after the addition of HCO3− or CO32−, owing to the carbonate or bicarbonate combination with the hydroxyl group on the probe Ir-1 to form a hydrogen bond. Such luminescent probe worked excellently in tetrahydrofuran with a quick response time (

A novel bifunctional chemosensor 1O constructed with diarylethene and pyridazine unit has been designed and synthesized with excellent photochromic properties upon UV/Vis radiation. The chemosensor 1O shows prominent selectivity and high sensitivity for Cd2+ and Zn2+ by obvious fluorescent enhancement with a low detection limit in water-acetonitrile solution (v(water):v(acetonitrile) = 1:9). The chemosensor 1O could be utilized as a fluorescent sensor for Cd2+ with a limit of detection (LOD) of 2.3 × 10−6 M. With the presence of Zn2+, the fluorescence of the generated zinc complex enhances remarkably and the limit of detection (LOD) for Zn2+ is calculated to be 1.1 × 10−5 M by Job’s plot titrations. A logic circuit of this chemosensor 1O has been constructed with the input signals of UV and visible light, Cd2+ (or Zn2+) and EDTA and the output signal of the emission intensity. In addition, the concentrations of Cd2+ or Zn2+ in real water are detected quickly and conveniently by this chemosensor.

A chemical sensor composed of pyridoxal hydrochloride schiff base based on diarylethene (1O) was synthesized. Its photochemical properties and selectivity to ions were further studied. The chemosensor could detect cyanide effectively and is almost undisturbed by other ions. When titrating CN−, the reaction aroused a distinct change in the absorption spectrum with the color change from transparent to yellow, and the fluorescence intensity centered at 562 nm was increased 68 folds. It also exhibited a good fluorescence sensing of Mg2+ with high selectivity and sensitivity. Upon addition of Mg2+, its emission intensity enhanced 110 folds, with the color change from dark to bright blue. Its good spectral response could be applied to molecular logic circuit. Moreover, the chemosensor could be made into test paper strips for the qualitative and quantitative detection of CN− and Mg2+.