Development of new methodologies for synthesizing polymers with novel structures and unique properties is a fundamentally important area in polymer science. Herein, a novel synthetic strategy to conjugated poly(p-arylene dihalodiene)s (PADs) with high regio- and stereoselectivity was developed. In the presence of PdBr and CuBr, the polymerizations of terminal alkynes proceeded smoothly in air without heating to generate PADs in high yields (up to 95.3%) with high molecular weights (M up to 915 900). Low-cost inorganic CuBr played dual roles as cocatalyst and comonomer. The PADs possessed good solubility and film-forming ability. Their thin films exhibited high refractive indices (1.7149-1.7245) and would be fabricated into well-resolved fluorescent photopatterns by photolithography. Thanks to the vinyl bromine functionality, the PADs could undergo efficient postmodification to afford polymers with more sophisticated structures and applications. ©

Gao Qingqing    Qiu Zijie    Mark robert james Elsegood    Chen Ming    Wang Jianguo    Ryan tsz kin Kwok    林荣业    唐本忠    

Macromolecules

2018

Red emitters are very important for colour displays and white lighting devices. However, efficient red emitters are relatively rare because they often suffer from the problem of aggregation-caused quenching. In this work, a series of robust red molecules consisting of tetraphenylethene, benzo-2,1,3-thiadiazole, phenanthro[9,10-d]imidazole and triphenylamine moieties are synthesized and fully characterized. The photophysical properties, transient fluorescence decay, thermal stability, and electrochemical behaviors and electronic structures are thoroughly investigated. The results show that these molecules have high thermal and electrochemical stabilities. They show aggregation-induced emission (AIE) properties and emit strong red fluorescence in the aggregated state, which can be well modulated by functional groups. Nondoped OLEDs are fabricated using these red molecules as light-emitting layers, offering red electroluminescence at 650 nm (CIE = 0.665, 0.334) and a high luminance and an external quantum efficiency of up to 6277 cd m and 2.17%, respectively. Moreover, a solution-processed red OLED with good performance is also achieved. This work not only presents efficient red emitters for nondoped OLEDs, but also provides useful structure-property relationship insights for further development of efficient red luminescent materials.

Li Yinghao    Wang Weigao    Zhuang Zeyan    Wang Zhiming    Lin Gengwei    Shen Pingchuan    陈书明    Zujin Zhao    唐本忠    

Journal of Materials Chemistry C

2018

The rapid development of healthcare techniques encourages the emergence of new molecular imaging agents and modalities. Fluorescence imaging that enables precise monitoring and detection of biological processes/diseases is extensively investigated as this imaging technique has strengths in terms of high sensitivity, excellent temporal resolution, low cost, and good safety. Aggregation-induced emission luminogens (AIEgens) have recently emerged as a new class of emitters that possess several notable features, such as high brightness, large Stokes shift, marked photostability, good biocompatibility, and so on. So far, AIEgens are widely explored and exhibit superb performance in the area of biomedicine and life sciences. Herein, this review summarizes and discusses the recent investigations of AIEgens for in vivo diagnosis and therapy including long-term tracking, 3D angiography, multimodality imaging, disease theranostics, and activatable sensing. Collectively, these results reveal that AIEgens are of great promise for in vivo biomedical applications. It is hoped that this review will lead to new insights into the development of advanced healthcare materials.

Qi Ji    Chen Chao    Ding Dan    唐本忠    

Advanced Healthcare Materials

2018

The development of polymeric materials with novel structures and unique properties and functionalities is of both academic and industrial significance. In this work, functional poly(dihalopentadiene)s were synthesized by boron trihalide-mediated multicomponent polymerization routes in a stereoselective manner. The polymerizations of tetraphenylethylene-containing diyne, BX (X = Cl, Br) and p-tolualdehyde proceed smoothly in dichloromethane under mild conditions to afford high molecular weight poly(dihalopentadiene)s with a predominant (Z, Z)-configuration in moderate to good yields. The reaction conditions and the boron trihalide used were found to have great effects on the stereochemistry of the resulting polymer structures. The obtained poly(1,5-dihalo-(Z, Z)-1,4-pentadiene)s possess high thermal stability and good film-forming ability. Their thin films show high refractive index of 1.9007-1.6462 in a wide wavelength region of 380-890 nm with low optical dispersion. The polymers are weakly emissive in dilute solutions but become highly emissive upon aggregated, demonstrating a unique phenomenon of aggregation-enhanced emission. Their nanoaggregates in aqueous media can serve as sensitive fluorescent chemosensors for the detection of explosives with a superamplification effect and a low detection limit.

Ting Han    Zhang Yun    Benzhao He    林荣业    唐本忠    

Polymers

2018

Hypoxanthine is a well-known indicator of intracellular energy status that is associated with many pathological conditions. We report a fluorescent luminogen (TPE-HPro) with aggregation-induced emission (AIE) feature which, along with xanthine oxidase (XO), detects and quantifies hypoxanthine in a “turn-on” manner. The superior detection performance of this fluorometric assay indicates its great potential for biomedical diagnostics.

Zhang Zhiling    Ryan tsz kin Kwok    Yong Yu    唐本忠     Ng Ka Ming   

Journal of Materials Chemistry B

2018

Deliberate design of specific and sensitive molecular probes with distinctive physical/chemical properties for analyte sensing is of great significance. Herein, by taking advantage of the position-dependent substituent effects, an aggregation-induced emission featured iron (III) probe from ortho-substituted pyridinyl-functionalized tetraphenylethylene (TPE-o-Py) is synthesized. It displays high sensitivity and selectivity toward iron (III) detection. The recognition arises from the position isomer of ortho-substitution, and the fact that TPE-o-Py has a low acid dissociation constant (pK ) that is close to that of hydrolyzed Fe. Importantly, TPE-o-Py as a light-up fluorescence probe could be employed for Fe sensing in living cells with a pronounced red-shift in fluorescence emission.

Feng Xing    Li Ying    He Xuewen    Liu Haixiang    Zheng Zhao    Ryan tsz kin Kwok    Mark robert james Elsegood    林荣业    唐本忠    

Advanced Functional Materials

2018

We studied the aggregation-induced emission (AIE) phenomenon in a nanoconfined environment, where the AIE-active molecule, namely, 1,1,2,2-tetrakis(4-methanoylphenyl)ethane (TPE-4ALD), was held in space via four acylhydrazone bonds within the thermosensitive microgel networks. The thermosensitive microgels, namely N-AH-TPE, were synthesized via the copolymerization of N-isopropylacrylamide (NIPAM) and 4-acylhydrazine-(2-hydroxy-3-(methacryloxypropyl)pyridine hydrochloride (AH monomer) with TPE-4ALD as cross-linker via surfactant free emulsion polymerization (SFEP) in aqueous solution at 70 °C. Acylhydrazone-bonded tetraphenylethene (TPE-4AH) moieties were thus constructed and worked as the fluorophore in N-AH-TPE microgels. The aqueous suspensions of N-AH-TPE microgels exhibit strongly bluish-green fluorescence under ultraviolet excitation because the four arms of TPE-4AH moieties were held and their intramolecular motions are strongly restricted. It is estimated that there is one TPE-4AH moiety per about 394 nm for the swollen N-AH-TPE microgels. The fluorescent properties of N-AH-TPE microgels can be modulated via the change of hydrophilic and hydrophobic environments of TPE-4AH moieties exerted by external stimuli, like addition of various good solvents for TPE-based structures, i.e., N,N-dimethylformamide (DMF), methanol, ethanol, tetrahydrofuran (THF), and N,N-dimethyl sulfoxide (DMSO), varying the solution temperature as well as the counteranions of the microgels. An unusual enhancement in the fluorescent intensity is observed when specific amounts of organic solvent are added into the aqueous suspensions of N-AH-TPE microgels, which can be attributed to the cononsolvency of the polyNIPAM network chains. The shrinkage of N-AH-TPE microgels caused by the cononsolvency effect further strengthens the confinement of TPE-4AH moieties and hence enhances the fluorescent emission of the microgels even though the organic solvents added are good solvents for TPE-4AH. Increasing the solution temperature of N-AH-TPE microgels or introducing hydrophobic counteranions into the microgels also significantly enhances the fluorescent emission of the microgels.

Xue Jinqiao    Bai Wei    Duan Han-Yi    Nie Jingjing    Binyang Du    Jingzhi Sun    唐本忠    

Macromolecules

2018

Far red/near-infrared (NIR) fluorescent materials possessing the characteristics of strong two-photon absorption and aggregation-induced emission (AIE) as well as specific targeting capability are much sought after for bioimaging and therapeutic applications for their deeper penetration depth and higher resolution. Herein, a series of dipolar far red/NIR AIE luminogens with strong push-pull effect are designed and synthesized. The obtained fluorophores display bright far red/NIR solid-state fluorescence with high quantum yield of up to 30%, large Stokes shifts of up to 244 nm and large two-photon absorption cross-section of up to 887 GM. Three neutral AIEgens show specific lipid droplets (LDs)-targeting capability, while the one with cationic and lipophilic characters tends to target the mitochondria specifically. All the molecules demonstrate good biocompatibility, high brightness and superior photostability. They also serve as efficient two-photon fluorescence imaging agents for clear visualization of LDs or mitochondria in living cells and tissues with deep-tissue penetration (up to 150 μm) and high contrast. These AIEgens can efficiently generate singlet oxygen upon light irradiation for photodynamic ablation of cancer cells. All these intriguing results prove that these far red/NIR AIEgens are excellent candidates for two-photon fluorescence imaging of LDs or mitochondria and organelle-targeting photodynamic cancer therapy.

Zheng Zheng    Zhang Tianfu    Liu Haixiang    Yuncong Chen    Ryan tsz kin Kwok    Ma Chao    Zhang Pengfei    Herman ho yung Sung    Ian Williams    林荣业    Kam sing Wong    唐本忠    

ACS Nano

2018

A pair of chiral R/S-TPE-BINOL derivatives with dark resonance energy transfer was facilely synthesized by coupling of a tetraphenylethylene (TPE) derivative, BODIPY dye and R/S-1,1′-bi-2-binaphthol (BINOL), where TPE not only was selected as a dark energy donor, but also can endow the target molecules with aggregation-induced emission (AIE) characteristics; BODIPY served as an energy acceptor; BINOL, one of the most popular axially chiral compounds, was employed as a chiral source. Due to the chiral feature of R/S-TPE-BINOL, obvious CD and CPL signals were observed in the solution and aggregated states. Generally, for organic dyes, high dissymmetric factor (g) values are often accompanied by low emission efficiencies. To improve emission efficiency, an effective strategy of dark through-bond energy transfer was adopted. This method makes it possible to avoid fluorescence leakage originating from donor emission. The energy of TPE can be completely transferred to the BODIPY unit before non-radiative relaxation with an energy transfer efficiency of up to 99% and a high quantum yield of 91%. Remarkably, these enantiomers could self-assemble into bowl-like hollow microspheres in a mixed solvent of THF/water to give a stable fluorescent suspension with tunable emission from the green to yellow region. Moreover, TPE-BOD was selected as the fluorescent probe for specific staining of lipid droplets in living cells.

Feng Hai-Tao    Xinggui Gu    林荣业    Yansong Zheng    唐本忠    

Journal of Materials Chemistry C

2018

Differentiating between live and dead cells is a critical step for biological researchers, clinical doctors and pharmaceutical engineers when evaluating cell viability, for determining compound cytotoxicity and in the development of effective treatments for many diseases. Usually, careful selection and combination of two different dyes are required to differentiate and image both live and dead cells. In this work, we present a new method that can differentiate, quantify and image both live and dead cells concurrently through the use of a single, cell-permeable, biochromic fluorescent dye. Two silole-based hemicyanine dyes, Silo-Cy and Silo-2Cy are designed and synthesized. These dyes exhibit green fluorescence in both live and dead cells but much stronger green and red fluorescence only from dead cells. By collecting signals from the two distinct channels, we are able to image and discriminate between live and dead cells through fluorescence microscopy and quantify the cell viability via flow cytometry.

Sijie Chen    Jianzhao Liu    Zhang Shouxiang    Engui Zhao    Yu Chris Y. Y.    Hushiarian Roozbeh    Yuning Hong    唐本忠    

Materials Horizons

2018