Fluorescent conjugated microporous polymers containing pyrazine moieties for adsorbing and fluorescent sensing of iodine

Two kinds of fluorescent conjugated microporous polymers containing pyrazine moieties were prepared by the polymerization reaction of 2,5-di-triphenylamine-yl-pyrazine (DTPAPz) and N,N,N',N'-tetrapheny-2,5-(diazyl) pyrazine (TDPz) with 2,4,6-trichloro-1,3,5-triazine (TCT) through Friedel-Crafts reaction using the methanesulfonic acid as a catalysts. Both CMPs have high thermal stability and decomposition temperature reaches above 596 and 248 °C under nitrogen atmosphere, respectively. By right of porous morphology and electron-donating nitrogen, as well as electron-rich π-conjugated structures, the adsorption performance for iodine vapor on the CMPs is very excellent, which can reach 441% and 312%. In addition, fluorescence studies showed that the two CMPs exhibited high fluorescence sensitivity to electron-deficient iodine, o-nitrophenol (o-NP), and picric acid (PA) via fluorescence quenching.

Synthesis of 1,6-disubstituted pyrene-based conjugated microporous polymers for reversible adsorption and fluorescence sensing of iodine

Four 1,6-disubstituted pyrene-based fluorescent conjugated microporous polymers were synthesized by Sonogashira–Hagihara reaction, trimerization reaction of –CN, and Friedel–Crafts reaction, respectively, which can efficient capture and sense I₂.

Excited State Intramolecular Proton Transfer Plus Aggregation-Induced Emission-Based Diketopyrrolopyrrole Luminogen: Photophysical Properties and Simultaneously Discriminative Detection of Trace Water in Three Organic Solvents

Developing solid state near-IR (NIR) emitters and simultaneously discriminative detection of trace water in organic solvents has long been a significant challenge. In this work, a novel diketopyrrolopyrrole-based luminogen (DPP1) with excited state intramolecular proton transfer (ESIPT) and aggregation-induced emission (AIE) characteristics has been designed and synthesized. Its amorphous and crystal solids show red and NIR-emissive fluorescence at 625 and 675 nm, respectively. When DPP1 reacts with fluoride anion, the resulting system (DPP1·F) can discriminatively detect the water content in aprotic solvents with colorimetric and fluorescent dual modes. Distinct fluorescent responses of "turn-on", "ratiometric turn-off", and "ratiometric turn-on" and low limits of detection of 0.0064, 0.042, and 0. The water-induced sensitive and fast change in THF was applied to the determination of water in foodstuffs in practical solid state indicator paper strips.

Fluorescent conjugated microporous polymer based on perylene tetraanhydride bisimide for sensing o-nitrophenol

A novel conjugated microporous polymer based on perylene tetraanhydride bisimide (DP₂A₂) has been synthesized through Sonogashira-Hagihara cross-coupling polymerization of tetrabromo-substituted perylene tetraanhydride bisimide derivative (DPBr₂ABr₂) with 1,4-diethynylbenzene, whose Brunauer-Emmett-Teller (BET) specific surface area is about 378 m² g^-1. The fluorescence quenching behaviors of the DP₂A₂ were investigated. It is found that the DP₂A₂ shows high sensitivity and selectivity to tracing o-nitrophenol (o-NP) in THF with Ks_V constant of 2.00 × 10⁴ L mol^-1. The detection limit (LOD) is 1.50 × 10^-9 mol L^-1. The possible sensing mechanism for the luminescent quenching of DP₂A₂ towards o-NP exciting at 365 nm was considered the donor-acceptor electron transfer mechanism, which is a combined result from both dynamic (collisional) and static quenching. Moreover, the static quenching process is dominant for DP₂A₂.

A covalent triazine-based framework from tetraphenylthiophene and 2,4,6-trichloro-1,3,5-triazine motifs for sensing o-nitrophenol and effective I2 uptake

A covalent triazine-based framework with a tetraphenylthiophene (TTPT) backbone was prepared by the AlCl₃ catalyzed Friedel–Crafts reaction of commercially available material 2,4,6-trichloro-1,3,5-triazine with tetraphenylthiophene in dichloromethane.

Synthesis and structural analysis of dimethylaminophenyl-end-capped diketopyrrolopyrrole for highly stable electronic devices with polymeric gate dielectric

The synthesis and structural analysis of DPP(PhNMe₂)₂, a stable diketopyrrolopyrrole derivative end-capped with a strongly electron-donating dimethylaminophenyl moiety is reported and the origin of ambient stability is analyzed in detail.

Fluorescence fiber-optic turn-on detection of trace hydrazine vapor with dicyanovinyl-functionalized triazatruxene-based hyperbranched conjugated polymer nanoparticles

A solution-processed triazatruxene-based hyperbranched conjugated polymer nanoparticle was applied for fluorescence fiber-optic detection of hydrazine vapor with a limit of detection down to 1.1 mg m⁻³ in 5 minutes.

Hyperbranched conjugated polymers containing 1,3-butadiene units: metal-free catalyzed synthesis and selective chemosensors for Fe3+ ions

Hyperbranched polymers containing 1,3-butadiene units in main chain were synthesized by transition-metal-free catalysis and investigated as chemosensors for Fe³⁺ ions.

Highly Efficient Thermally Activated Delayed Fluorescence in Dinuclear Ag(I) Complexes with a Bis-Bidentate Tetraphosphane Bridging Ligand

A series of highly emissive neutral dinuclear silver complexes [Ag(PPh₃)(X)]₂(tpbz) (tpbz = 1,2,4,5-tetrakis(diphenylphosphanyl)benzene; X = Cl (1), Br (2), I (3)) was synthesized and structurally characterized. In the complexes, the silver atoms with tetradedral geometry are bridged by the tpbz ligand, and the ends of the molecules are coordinated by a halogen anion and a terminal triphenylphosphine ligand for each silver atom. These complexes exhibit intense white-blue (λ_max = 475 nm (1) and 471 nm (2)) and green (λ_max = 495 nm (3)) photoluminescence in the solid state with quantum yields of up to 98% (1) and emissive decay rates of up to 3.3 × 10⁵ s^-1 (1) at 298 K. With temperature decreasing from 298 to 77 K, a red shift of the emission maximum by 9 nm for all these complexes is observed. The temperature dependence of the luminescence for complex 1 in solid state indicates that the emission originates from two thermally equilibrated charge transfer (CT) excited states and exhibits highly efficient thermally activated delayed fluorescence (TADF) at ambient temperature. At 77 K, the decay time is 638 μs, indicating that the emission is mainly from a triplet state (T₁ state). With temperature increasing from 77 to 298 K, a significant decrease of the emissive decay time by a factor of almost 210 is observed, and at 298 K, the decay time is 3.0 μs. The remarkable decrease of the decay time indicates that thermal population of a short-lived singlet state (S₁ state) increases as the temperature increases. The charge transfer character of the excited states and TADF behavior of the complexes are interrogated by DFT and TDDFT calculations. The computational results demonstrate that the origin of TADF can be ascribed to ^1,3(ILCT + XLCT+ MLCT) states in complexes 1 and 2 and ^1,3(XLCT) states mixed with minor contributions of MLCT and ILCT in complex 3.

Structurally defined nanographene-containing conjugated polymers for high quality dispersions and optoelectronic applications

A new conjugated polymer with nanographenes shows excellent dispersibility in N-cyclohexyl-2-pyrrolidone and remarkable emission from exfoliated nanographenes.

Amphiphilic gels of solvatochromic fluorescent poly(2-oxazoline)s containing D–π–A pyrenes

We report amphiphilic, fluorescent, solvatochromic poly(2-methyl-2-oxazoline) (POZO-py) and poly(2-ethyl-2-oxazoline) (PEtOZO-py), which contain D–π–A pyrene dye units in their side chains.

Conjugated Polymer Nanoparticle-Triplet Emitter Hybrids in Aqueous Dispersion: Fabrication and Fluorescence Quenching Behavior

Conjugated polymer nanoparticles based on poly[9,9-bis(2-ethylhexyl)fluorene] and poly[N-(2,4,6-trimethylphenyl)-N,N-diphenylamine)-4,4'-diyl] are fabricated using anionic surfactant sodium dodecylsulphate in water by miniemulsion technique. Average diameters of polyfluorene and polytriarylamine nanoparticles range from 70 to 100 and 100 to 140 nm, respectively. The surface of the nanoparticles is decorated with triplet emitting dye, tris(2,2'-bipyridyl)ruthenium(II) chloride. Intriguing photophysics of aqueous dispersions of these hybrid nanoparticles is investigated. Nearly 50% quenching of fluorescence is observed in the case of dye-coated polyfluorene nanoparticles; excitation energy transfer is found to be the dominant quenching mechanism. On the other hand, nearly complete quenching of emission is noticed in polytriarylamine nanoparticle-dye hybrids. It is proposed that the excited state electron transfer from the electron-rich polytriarylamine donor polymer to Ru complex leads to the complete quenching of emission of polytriarylamine nanoparticles. The current study offers promising avenues for developing aqueous solution processed-electroluminescent devices involving a conjugated polymer nanoparticle host and Ru or Ir-based triplet emitting dye as the guest.