AIE-active Polymers for Explosive Detection

Super-sensitive and ultra-selective detection of explosives plays a crucial role in anti-terrorism operations, homeland security, civilian safety and environment protection. Among the developed fluorescent probes, the polymers with aggregation-induced emission （AIE） characteristics have drawn much attention due to their bright emission in the aggregate and solid states. However, no review has summarized the development of AIE-active polymers for explosive detection. Herein, we reviewed the recent progress on using AIE-active polymers to detect explosives with super-amplification quenching effect. Moreover, the challenges and opportunities in this area were also briefly discussed.

New tetraphenylpyridinium-based luminogens with aggregation-induced emission characteristics

The research on aggregation-induced emission (AIE) has drawn increasing interests in the past decade. With the efforts scientists paid, a variety of AIE systems have been developed, among which the tetraphenylethelene and silole derivatives are the most studied. Development of new AIE systems could further enrich the AIE molecules and promote the development of AIE area. In this communication, we prepared a new AIE system based on 1,2,4,6-tetraphenylpyridinium ions according to the restriction of intramolecular rotation mechanism. These molecules could be facilely synthesized via one-step and one-pot reaction. The ionic AIE-active molecules could find wide application in sensing and optoelectronic areas.

A Silole-Based Efficient Electroluminescent Material with Good Electron-Transporting Potential

A new silole derivative, 2,5-bis（7-（dimesitylboranyl）-9,9-dimethylfluoren-2-yl）- 1 -methyl- 1,3,4-triphenylsilole （（MesBF）2MTPS）, is synthesized and characterized. （MesBF）2MTPS shows a good fluorescence efficiency of 15% in THF solution and a higher efficiency of 86% in solid film, presenting an aggregation-enhanced emission charac- teristic. It is thermally and morphologically stable, with high decomposition and glass-transition temperatures of 257 and 171 ℃, respectively. The LUMO energy level （-2.96 eV） of （MesBF）zMTPS is lower than that of TPBi, revealing its electron-transporting potential. Efficient organic light-emitting diodes （OLEDs） are fabricated using （MesBF）2MTPS as emitter, which radiates yellow light at 554 nm, and affords high maximum luminance, current efficiency, and external quantum efficiency of 48348 cd·m^-2, 12.3 cd·A^-1, and 4.1%, respectively.

Effective enhancement of the emission efficiency of tetraphenylporphyrin in solid state by tetraphenylethene modification

Tetraphenylporphyrin(TPP) is a typical red-emitting luminogen showing evident aggregation caused quenching(ACQ) effect. To enhance its emission efficiency in solid state, four tetraphenylethene(TPE)units were attached to the four meso-positions of TPP core via ester group through a facile and efficient route. The derived compound(4(TPE-COO)-TPP) emits red fluorescence(peak at 655 nm) with a good quantum efficiency(F) of 7.5%, which is much higher than that of TPP(Φ～ 0.1%). In molecular aggregate formed in tetrahydrofuran(THF) and water mixtures, 4(TPE-COO)-TPP has a relative high F of 12%. The evidently subdued ACQ behavior can be ascribed to the propeller shape and bulky size of the TPE units,which prevent the close packing and strong p-p interaction of TPP cores. The loose molecular packing and weak interchromophore interactions were validated by different characterization methods including UV-visible absorption, steady state and transient fluorescence spectroscope, X-ray diffraction and scanning electronic microscope observations. It is noted that 4(TPE-COO)-TPP has an emission efficiency of 14.4% in dilute THF solution. This is due to the conjugation break between the TPP and TPE moieties, the rotational and vibrational motions of the phenyl groups cannot quench the fluorescence of 4(TPE-COO)-TPP.

Self-healing hyperbranched polytriazoles prepared by metal-free click polymerization of propiolate and azide monomers

The last decade has witnessed the quick develop of self-healing materials. As a newborn strategy, the alternative of irreversible covalent bond formation is, however, to be further developed. In this paper, self-healing hyperbranched poly(aroxycarbonyltriazole)based on such mechanism were prepared by our developed metal-free click polymerization of simplified dipropiolate and triazide. Thanks to their excellent processability and film-forming ability, high quality homogeneous films free from defects were obtained by casting. The cut films could be healed by stacking or pressing the halves together at room temperature and elevated temperature. Thus, this design concept for self-healing materials should be generally applicable to other hyperbranched polymers with reactive groups on their peripheries.

3,4,5-Triphenyl-1,2,4-triazole-based multifunctional n-type AIEgen

The luminogens with aggregation-induced emission(AIEgens) characteristics have been widely applied in diverse areas. However,the n-type AIEgens are to be further developed. In this paper, we designed and synthesized an n-type multifunctional AIEgen of tetraphenylethene-substituted 3,4,5-triphenyl-4H-1,2,4-triazole(BTPE-TAZ). This AIEgen can serve as both light-emitting and electron-transporting layers in organic light-emitting devices. Moreover, it also exhibits the interesting optical waveguide and reversible mechanochromic luminescence properties, which are of great potential for practical applications.

AIEgen based light-up probes for live cell imaging

Fluorescent light-up probes comprising a tetraphenylethene unit with aggregation-induced emission(AIE)characteristics and a water-soluble peptide have been designed and synthesized which provide cell membrane and nuclear permeability to live cells.This strategy has offered new opportunities for the development of probes with light-up ability and good signal-to-noise ratio.The selectivity or targeting specificity is determined by the peptide sequence,i.e.a nuclear localization signal that leads to nucleus imaging and a cell biomarker targeting peptide that offers specific light-up imaging of HT-29 cells.

New tetraphenylpyridinium-based luminogens with aggregation-induced emission characteristics

The research on aggregation-induced emission(AIE)has drawn increasing interests in the past decade.With the efforts scientists paid,a variety of AIE systems have been developed,among which the tetraphenylethelene and silole derivatives are the most studied.Development of new AIE systems could further enrich the AIE molecules and promote the development of AIE area.In this communication,we prepared a new AIE system based on1,2,4,6-tetraphenylpyridinium ions according to the restriction of intramolecular rotation mechanism.These molecules could be facilely synthesized via one-step and one-pot reaction.The ionic AIE-active molecules could find wide application in sensing and optoelectronic areas.

An air-stable supported Cu(?) catalyst for azide-alkyne click polymerization

An air-stable supported Cu(I) catalyst, Cu I@PS-Phen, was designed and synthesized. Cu I@PS-Phen can efficiently catalyze the click polymerization of diynes a and diazides b to produce soluble and thermally stable polytriazoles with high molecular weights(Mw up to 30800), and low copper residue content(down to 190 ppm) in high yields(up to 94.2%) under mild reaction conditions without the exclusion of oxygen.

Blue fluorophores comprised of tetraphenylethene and imidazole： aggregation-induced emission and electroluminescence

By melting tetraphenylethene （TPE） and 1,2,4,5-tetraphenyl-lH-imidazole （TPI） units together through different linking positions, three new fluorophores are synthesized, and their optical, electronic and electro- luminescence （EL） properties are fully studied. Owing to the presence of TPE unit（s）, these fluorophores are weak emitters in solutions, but are induced to emit strongly in the aggregated state, presenting typical aggregation-induced emission characteristics. The experimental and computational results reveal that different connection patterns between TPE and TPI could impact the molecular conjugation greatly, leading to varied emission wavelength, fluorescence quantum yield and EL performance in organic light emitting diodes （OLEDs）. The fluorophore built by attaching TPE unit to the 1-position of imidazole ring shows bluest fluorescence, and its EL device emits at deep blue region （445 nm; CIE= （0.16, 0.15））. And the device based on the fluorophore by linking TPE to the 2- position of imidazole ring shows EL at 467 nm （CIE= （0.17, 0.22）） with good efficiencies of 3.17 cd.A ^-1, and 1.77%.