Congbin Fan

A highly sensitive fluorescent sensor for Al3+ and Zn2+ based on a diarylethene salicylhydrazide Schiff base derivative and its bioimaging in live cells

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.

A diarylethene-based fluorescent chemosensor for the sequential recognition of Fe3+ and cysteine

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 highly selective fluorescent chemosensor for Fe3+ based on a new diarylethene with a rhodamine 6G unit

Herein, a new diarylethene derivative bearing rhodamine 6G (1O) was synthesized via Schiff base condensation. It exhibited a sensitive response to Fe3+ with the solution changing from colorless (no fluorescence) to distinct pink (strong fluorescence) due to the transformation of the spirolactam ring to the open ring of rhodamine 6G. The diarylethene derivative bound to Fe3+ in the binding stoichiometry of 1u2006:u20061, and the limit of detection (LOD) of the 1O chemosensor for Fe3+ detection was found to be 65 nM. In addition, 1O exhibited an obvious acidichromism to TFA and could function as a reversible fluorescence photoswitch in response to UV/vis light irradiation. Based on these observations, a logic circuit was constructed with the combinational stimuli of UV/vis light and Fe3+/EDTA as inputs and the fluorescent emission intensity at 585 nm as the output.

Cyanobenzene-containing tetraphenylethene derivatives with aggregation-induced emission and self-recovering mechanofluorochromic characteristics

We report two constitutional isomers based on tetraphenylethene and cyanobenzene units via typical Suzuki coupling reaction. These target luminogens show obvious aggregation-induced emission (AIE) and self-reversible mechanofluorochromic characteristics.

A highly selective and sensitive fluorescent chemosensor for Zn2+ based on a diarylethene derivative

A promising photochromic fluorescent chemosensor 1o linked with Schiff base unit was synthesized. It displayed outstanding photochromism and a superb fluorescence turn-on response toward Zn2+. Upon the addition of Zn2+ to 1o, the fluorescent color of the solution obviously changed from blue to bright green with a 27-fold fluorescent intensity increase. The combination of 1o–Zn2+ with 1u2006:u20061 stoichiometry was verified by Jobs plot and MS analysis. The detection limit for 1o toward Zn2+ was measured to be 8.10 × 10−8 M. Furthermore, logic gate research was established with Zn2+, UV and visible light as input signals and the emission intensity as the output signal.

A diarylethene-based “on–off–on” fluorescence sensor for the sequential recognition of mercury and cysteine

A novel photochromic diarylethene with a quinoline unit was synthesized with multi-controllable fluorescence switching properties, which could be induced by light, mercury (Hg2+) and cysteine (Cys). Because the diarylethene displayed obvious fluorescence quenching with Hg2+ and the fluorescence was recovered to its original state evidently with Cys, it could sequentially recognize Hg2+ and Cys. Additionally, a logic circuit was constructed with the fluorescence intensity at 468 nm as output, and the combined stimuli of light and chemicals as inputs.

A fluorescent chemosensor for Sn2+ and Cu2+ based on a carbazole-containing diarylethene

A novel diarylethene with a carbazole moiety was developed for the highly selective and sensitive detection of Sn2+ and Cu2+ in methanol. Its fluorescence was enhanced with a 76 nm blue shift and selective fluorescence quenching occurred upon the addition of Sn2+ and Cu2+, respectively, over a wide range of tested cations. The compound formed complexes with Sn2+ and Cu2+ in a 1u2006:u20061 stoichiometry and has the detection limits of 1.9 μM and 1.2 μM, respectively. Moreover, the compound can be applied to detect Sn2+ and Cu2+ in natural water samples with high accuracy.

A highly selective fluorescent chemosensor for Cu2+: synthesis and properties of a rhodamine B‐containing diarylethene

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 297xa0nm light based on the intramolecular fluorescence resonance energy transfer mechanism. In an acetonitrile: water binary solvent (1: 1xa0v/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 2.86xa0×xa010-8 xa0molxa0L-1 . Using Cu2+ and UV light as the chemical inputs, and fluorescence intensity at 597xa0nm 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.

Synthesis and Fluorescence Switching of a New Photochromic Diarylethene

A new photochromic diarylethene compound, 1-[2-methyl-5-(4-pyridine) -3-thienyl]-2-[2-methyl-5-(4-methoxylphenyl)-3-thienyl]perfluorocyclopentene(1a) was synthesized. its photochromism was investigated. It showed good photochromism both in solution and PMMA amorphous film upon photoirradiation. Its fluorescence properties in the solution also were reaearched.

A highly selective fluorescent probe for detection of Cd2+ and HSO3− based on photochromic diarylethene with a triazole-bridged coumarin-quinoline group

A novel photochromic diarylethene containing a quinoline-linked 3-aminocoumarin Schiff base unit (1O) was synthesized and used for the selective detection of Cd2+ and HSO3−. The synthesized probe exhibited a straightforward response for the selective detection of Cd2+. Its fluorescence emission red-shifted ∼126 nm and was enhanced 24.9 fold in the presence of Cd2+. Meanwhile, the fluorescence color of 1O changed from dark cyan to golden yellow. The binding stoichiometry between 1O and Cd2+ was determined to be 1u2006:u20061. A molecular logic circuit with three inputs and one output was successfully constructed with its light and metal-responsive behaviors. In addition, 1O was able to selectively recognize HSO3− with a 135-fold enhanced fluorescence emission and a notable fluorescence color change from dark cyan to bright cyan. The 1H NMR and mass spectrometry analyses suggest that the HSO3− sensing of 1O is based on the hydrolysis of the Schiff base group of 1O.