Α-cyanostilbene Derivative Research Articles

Investigation of Charge-Transfer Interaction in Mixed Stack Donor–Acceptor Cocrystals Toward Tunable Solid-State Emission Characteristics

The formation of three mixed binary charge transfer (CT) cocrystals with tunable photoluminescence behavior featuring both CT interaction and directional hydrogen bonding is presented. Our strategy consists of the CT induced cocrystallization of three polycyclic (naphthalene, anthracene, and pyrene) carrying α-cyanostilbene (CS) derivatives, namely, 3-(naphthalene-2-yl)-2-(p-tolyl) acrylonitrile (NPA), 3-(anthracene-9-yl)-2-phenylacrylonitrile (APA), and 2-(4-methoxyphenyl)-3-(pyrene-1-yl) acrylonitrile (MPA) as donors (D) with 1,2,4,5-tetracyanobenzene (TCNB) as an acceptor (A). The as-prepared cocrystals were probed in detail by various analytical techniques, namely, X-ray diffraction data, vibrational spectroscopy, diffuse reflectance absorption spectroscopy, fluorescence properties, and fluorescence quantum yields and lifetimes, affirming the formation of CT complexes. Complex IA features a mixed stack arrangement (D–A–D–A–D), while IIA and IIIA revealed (DAD---DAD) stack arrangement. The CT products ...

Supramolecular Fluorescent Polymers Containing α-Cyanostilbene-Based Stereoisomers: Z/E-Isomerization Induced Multiple Reversible Switching

Photoresponsive materials play an important role in smart sensors and readable optical devices. The α-cyanostilbene moiety gathers Z/E-isomerization, mesogenic, and aggregation-induced enhanced emission (AIEE) properties together and can be considered as a multifunctional building block bearing luminogen, AIEgen, mesogen, and chromphore characteristics. Here, we report isomerization induced a series of notable reversible switching based on α-cyanostilbene containing hydrogen-bonded supramolecular polymers. Z- and E-stereoisomers of dendritic α-cyanostilbene derivatives (Z-CNBP and E-CNBP) were hydrogen-bonded with poly(4-vinylpyridine) (P4VP), giving rise to P4VP(Z-CNBP)x and P4VP(E-CNBP)x. P4VP(Z-CNBP)x exhibit a hexagonal columnar (Φh) phase at 0.4 ≤ x ≤ 1.0, while the lamellar phase could be formed for P4VP(E-CNBP)x at 0.3 ≤ x ≤ 0.7. P4VP(Z-CNBP)0.8 shows photothermal E/Z-isomerization induced reversible switching, including phase structures, surface topographies, birefringence, and fluorescence proper...

Two novel AIEE-active imidazole/ α-cyanostilbene derivatives: photophysical properties, reversible fluorescence switching, and detection of explosives

Novel imidazole derivatives containing the α-cyanostilbene unit can act as reversible acid/base stimulated fluorescence switches in the solid state, as chemosensors for explosives detection in aqueous systems, and as test strip detectors.

A Λ-shaped cyanostilbene derivative: multi-stimuli responsive fluorescence sensors, rewritable information storage and colour converter for w-LEDs

A new Λ-shaped α-cyanostilbene derivative (TSA) containing an active amino group with fluorescence emission both in solution and the solid state was designed, synthesized and characterized. TSA can be used as a fluorescent sensor, a rewritable information storage material and in w-LEDs.

Self-assembly, AIEE and mechanochromic properties of amphiphilic α-cyanostilbene derivatives

A series of amphiphilic α-cyanostilbene derivatives consisting of an α-cyanostilbene rodlike core with lipophilic and flexible alkyl chains at one end and a polar glycerol group at the opposite end have been synthesized and investigated by polarizing microscopy, DSC, X-ray scattering, SEM, UV-vis spectroscopy and photoluminescence measurements. These compounds can self-assemble into liquid crystalline phase sequence of SmA- Colhex/p6mm- CubI/Pm3¯n in the bulk states and multistimuli responsive organogels in organic solvents. They have reversible photoresponsive properties in solution, liquid crystalline state and gel state. They also show aggregation-induced enhanced emission (AIEE) property, meanwhile, they present excellent mechanochromic behavior and have a good reversibility of fluorescence conversion upon grinding-fuming process.

Terpyridine functionalized α-cyanostilbene derivative as excellent fluorescence and naked eyes Fe2+ probe in aqueous environment

A novel carbazole derivative (L) functionalized by terpyridine was designed and synthesized. Its structure was fully characterized by FT-IR, HR-MS, 1H NMR spectra. L formed J-aggregates and possessed aggregation-induced emission enhancement property in aqueous environment. In addition, compound L showed specific response to Fe2+ in UV–vis spectra at 557 nm in EtOH–H2O mixed solvent, owing to metal-to-ligand-charge-transfer (MLCT). The emission quenched much more sharply than other metal ions when adding Fe2+. The interaction between compound L and Fe2+ was analyzed by UV–vis and fluorescence spectrum titration. The limit of detection was calculated to be 1.63 μM. The stoichiometric of L and Fe2+ was 2:1 confirmed by Job’s plots. Competition experiment indicated that other metal ions caused little interference. In this way, L could be a fluorescent and “naked eyes” probe for Fe2+ detection. This dual mode Fe2+ sensor can be considered to have potential value in practical applications.

Quantitative and highly selective sensing of sodium houttuyfonate via long-aliphatic chains hydrophobic assembly and aggregation-induced emission

An α-cyanostilbene derivative was synthesized for the selective detection of sodium houttuyfonate via AIEE with an obvious fluorescence enhancement.

Complex-formation-enhanced fluorescence quenching effect for efficient detection of picric acid.

Amine-functionalized α-cyanostilbene derivatives (Z)-2-(4-aminophenyl)-3-(4-butoxyphenyl)acrylonitrile (ABA) and (Z)-3-(4-butoxyphenyl)-2-[4-(butylamino)phenyl]acrylonitrile (BBA) were designed for specific recognition of picric acid (PA), an environmental and biological pollutant. The 1:1 host-guest complexes formed between the chemosensors and PA enhanced fluorescence quenching, thus leading to sensitive and selective detection in aqueous media and the solid phase.

Schiff base modified α-cyanostilbene derivative with aggregation-induced emission enhancement characteristics for Hg2+ detection

A Schiff base functionalized α-cyanostilbene derivative (TS) has been synthesized via a simple and straightforward method and characterized by FT-IR, 1H NMR, 13C NMR and mass spectra. TS possessed excellent AIEE properties and exhibited “turn-on” fluorescent responses to Hg2+. The results of UV–vis and fluorescence titration experiments revealed that TS was selective and sensitive to Hg2+ in pure THF and aqueous environment. The coordination of TS and Hg2+ ions generated TS–Hg complex locked the “dancing molecule” because of the flexible chain in the middle of the molecule and the complex was lower soluble induced formation of large aggregates that further limited the non-radiative relaxation channel enhanced emission after adding Hg2+ ions in aqueous solution, which had been confirmed by 1H NMR and dynamic light scattering (DLS).

Concurrent supramolecular gelation and fluorescence turn-on triggered by coordination of silver ion

By adding silver ion to the non-fluorescent solution of a pyridine functionalized α-cyanostilbene derivative, an immediate gelation accompanying a high-contrast fluorescence turn-on was effectively generated. The silver ion-coordinated highly fluorescent gel underwent reverse gel-to-sol transition restoring the non-fluorescent sol state upon reaction with tetrabutylammonium fluoride. Silver nanoparticles embedded in the fluorescent gel film were fabricated by in situ UV-light irradiation, which induced the surface plasmon effect on the fluorescence emission.

Media Effect upon the Fluorescence Ability of Differently Substituted α-Cyanostilbenes

Abstract The steady state and dynamic photophysical characteristics of α-cyanostilbene derivatives have been investigated in solution and in Polyvinylchloride (PVC) film at 300 K as well as in a frozen matrix at 77 K. While no emission is observed in solution, a significant fluorescence ability is registered both in PVC and frozen media. This fact is attributed to the matrix effect, which lessens the possible intramolecular motions around the central double bond. No phosphorescence at 77 K is observed. The fluorescence lifetimes at 77 K are compared with literature data for similar chemically fixed structures.