Polyhydroamination of alkynes is an important methodology for preparing nitrogen-containing polymers. At present, all of the reported polyhydroamination of alkynes proceed through nucleophilic addition, and no straightforward electrophilic polyhydroamination has been reported. In this paper, a novel copper-catalyzed electrophilic polyhydroamination of alkynes was developed, and soluble and thermally stable poly(enamine)s with high weight-average molecular weights (Mws, up to 12 650) were produced in excellent yields (up to 95%) under mild reaction conditions. Moreover, the regioselectivity of this electrophilic polyhydroamination could be tuned by adjusting one of the substitutions of internal diynes from phenyl to alkyl group. By introducing the tetraphenylethene moiety into polymer backbones, the resultant polymers exhibit unique aggregation-induced emission feature, and their aggregates could be used to sensitively detect explosives. This efficient polymerization will open up enormous opportunities for preparing functional nitrogen-containing acetylenic polymers applicable in diverse areas.

Photoactivatable probes for lipid droplets (LDs)-specific live-cell imaging are powerful tools for investigating their biological functions through precise spatial and temporal control. Ideal photoactivatable probes for LDs imaging require high concentration accumulation of fluorophores in LDs, simple synthetic procedures, and excellent photoactivation efficiency. However, it is difficult to overcome these challenges by conventional fluorophores due to aggregation-caused quenching (ACQ). In this study, a new class of photoactivatable and LDs-specific fluorescent probes was developed based on dihydro-2-azafluorenones, which can easily undergo photooxidative dehydrogenation reaction to afford 2-azafluorenones with aggregation-induced emission (AIE) properties. Dihydro-2-azafluorenones as photoactivatable and LDs-specific probes display significant advantages of excellent photoactivation efficiency and lack of self-quenching in the aggregated state, and are expected to have broad applications in study of biological functions of LDs' through light-controlled spatiotemporal imaging.

Lysosomes are involved in a multitude of cellular processes and their dysfunction is associated with various diseases. They are the most acidic organelles (pH 3.8–6.6, size 0.1–1.2 μm) with the highest viscosity (47–190 cP at 25 °C) in the cell. Because of their acidity, pH dependent non-AIE active fluorescent lysosomal probes have been developed that rely on protonation inhibited photoinduced electron transfer (PET). In this work, an acidic pH independent lysosome targetable piperazine–TPE (PIP–TPE) AIEgen has been designed with unique photophysical properties making it a suitable probe for quantifying viscosity. In a non-aggregated state PIP–TPE shows deep-blue emission as opposed to its yellowish-green emission in the bulk. It possesses high specificity for lysosomes with negligible cytotoxicity and good tracing ability due to its better photostability compared to LysoTracker Red. In contrast to most known lysosome probes that rely solely on PET, restriction of intramolecular motion (RIM) due to the larger viscosity inside the lysosomes is the mechanism responsible for PIP–TPE’s fluorescence. PIP–TPE’s high selectivity is attributed to its unique molecular design that features piperazine fragments providing a perfect balance between lipophilicity and polarity.

The polyhydroXations, such as polyhydrothiolation and polyhydroamination, of alkynes have been well-established. However, the polyhydroalkoxylation is rarely reported. In this paper, the polyhydroalkoxylation of aromatic diynes was successfully developed in the presence of a superbase, phosphazene base (t-BuP4). A series of soluble and regio-regular anti-Markovnikov additive poly(vinyl ether)s with high molecular weights (Mw up to 40 600) were obtained in high yields (up to 99%). All the polymers are thermally and morphologically stable. The tetraphenylethene (TPE)-containing P1a2a, P1a2b and P1a2c showed unique aggregation-enhanced emission (AEE) characteristics, and their aggregates could be used for explosive detection with a superamplification quenching effect. The poly(vinyl ether)s are degradable under acidic conditions. Thus, this work not only established a new polymerization but also generated a series of functional polymeric materials that are potentially applicable in optoelectronic and biomedical fields.

Typical optoelectronic devices are transducers used to realize energy conversion between light and electric current. Optoelectronic devices have a wide variety of applications as diverse as e.g. light-emitting diodes, photovoltaic technology, photoconductive cells, laser diodes, photoemissive camera tubes, optocouplers etc. Their versatile utility necessitates a cost-efficient industrial-scale production. The last decade has witnessed a rapid development and great improvement in the efficiency of optoelectronic devices and revealed their evergrowing need in new organic semiconducting materials that are at the heart of such devices. This review article covers the electronic properties of silole-based organic semiconductors including tetraarylsilole, spirosilole, fused silole molecules and polymers, recently applied in OLEDs and OPVs, and their optoelectronic device performances. And an outlook on the future investigations of silole-based materials is offered.

Luminescent materials without conventional aromatic groups have attracted extensive attention in recent years. However, the luminescence mechanism has been obscure and debatable. In the present study, based on oligo(maleic anhydride)s (OMAhs), alternative polymer of poly[(maleic anhydride)-alt-(2,4,4-trimethyl-1-pentene)] (PMP) and copolymers containing different ratios of OMAhs, we have proposed that the luminescence of OMAhs stems from the cluster. Moreover, a mechanism of clusteroluminescence was studied in detail with the assistance of theoretical simulation, which attributed the phenomenon to the intra- and inter-chain n → π* interaction of carbonyl groups of SAh units in OMAhs. Thus, the proposed study will give insights into designing luminescent materials with nonconventional groups.

Lipid droplets (LDs) as dynamic organelles are associated with many metabolic processes. Ideal fluorescent probes for LD-specific imaging require excellent specificity, superior brightness, fast cell permeability, and easy preparation. However, conventional fluorophores for LD imaging suffer from drawbacks of aggregation-caused quenching (ACQ), poor photostability, and difficulty of preparation. To tackle these challenges, herein, we develop an easily accessible aggregation-induced emission (AIE) fluorescent probe for LD-specific imaging and dynamic movement tracking. This AIE probe has significant advantages in terms of fast cell permeability, low cytotoxicity, strong photostability, and high two-photon absorption cross-sections in the near infra-red (NIR) range. It is thus expected to have broad applications in the study of LDs' biological functions.

Correction for ‘Light up detection of heparin based on aggregation-induced emission and synergistic counter ion displacement’ by Shiwu Li et al., Chem. Commun., 2017, 53, 4795–4798

Heparin is a widely used anticoagulant and the quantification of heparin concentration is pivotal for clinical use. However, previous fluorescent probes for heparin detection are usually based on fluorophores with aggregation-caused quenching (ACQ) properties, which severely restrict their applications for quantitative measurement of heparin in a wide range. Herein, we develop an aggregation-induced emission (AIE) probe HPQ-TBP-I for light up detection of heparin based on the electrostatic interaction-triggered formation of the HPQ-TBP/heparin complex and simultaneous displacement of the fluorescence quencher iodide ion. A linear relationship from 0 to 14 μM of heparin accompanied with a low detection limit of 22 nM was achieved, which fully covers the whole clinical dose range (1.7–10 μM). It is anticipated that this easily accessible and sensitive AIE probe is promising for clinical applications.

Tetraphenylfuran (TPF) and its control molecule tetraphenylthiophene (TPT), which are structurally similar to the aggregation-induced emission (AIE) active 2,3,4,5-tetraphenylsilole, were synthesized. Surprisingly, investigation of its photo-physical properties showed that TPF exhibits the aggregation-caused quenching effect instead of AIE characteristics, whereas TPT exhibits a quite weak AIE effect. Combining experimental results and theoretical calculations, this phenomenon was concluded to be co-caused by the restriction of intramolecular rotation (RIR), the mechanism of AIE, and the conjugation effect. Thus, this work provides an insight into RIR, which will greatly promote the development of AIE.

The transition-metal catalyzed and metal-free click polymerizations have been developed as powerful tools for the construction of functional polymers with linear and hyperbranched structures. The latter provides a thorough solution for the completely removing metallic residues from the products encountered in the former. Compared to the activated alkyne–azide metal-free click polymerization, the activated azide–alkyne one is rarely studied. In this Communication, a perfluorophenyl-activated azide of hexane-1,6-diyl-bis(4-azido-2,3,5,6-tetrafluorobenzoate) is rationally designed and facilely prepared. Through systematical optimization of the reaction conditions, an efficient metal-free perfluorophenylazide–alkyne polycycloaddition is established, and polytriazoles with high molecular weights (up to 166 000) and excellent solubility are obtained in excellent yields (up to 93%) under mild reaction conditions. Interestingly, the regioselectivity of the reaction could be fine-tuned by the solvents and diyne monomers. Therefore, this work provides not only a powerful tool for the preparation of functional polytriazoles, but also an attractive method for fine-tuning their regioregularity.

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.

Aggregation-induced emission (AIE) is a unique photo-physical phenomenon and has become an emerging and hot research area. With the enthusiastic efforts paid by researchers, hundreds of AIE-active luminogens (AIEgens) have been generated but heterocyclic AIEgens are rarely reported. Recently, we enriched the family of AIEgens and reported a pyrazine-based AIEgen of tetraphenylpyrazine (TPP), which could be facilely functionalized by a post-synthetic strategy. In this work, we further expanded the TPP-based AIE system by covalently attaching one, two or four electron-donating triphenylamine moieties to the TPP core via Suzuki coupling, and TPP–TPA, TPP–2TPA and TPP–4TPA were produced, respectively. Thanks to their donor-π-acceptor structures, these luminogens exhibit multi-functional properties, such as excellent thermal stability (up to 504 °C), large molar absorptivity, bright emission in the solid state (quantum yields up to 35.2%), solvatochromism, and high two-photon absorption cross-sections (up to 480 GM). Furthermore, using TPP–TPA as the emitting layer, a triple-layer device was fabricated and a turn-on voltage, maximum luminance, current efficiency, power efficiency, and external quantum efficiency of 3.7 V, 17459 cd m−2, 5.49 cd A−1, 3.18 lm W−1 and 2.88% were realized, respectively. These results indicate a huge potential to develop high-tech applications based on these TPP-based AIEgens.

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.

Amines play vital roles in agricultural, pharmaceutical, and food industries, but volatile amine vapors are serious threats to human health. Previously reported fluorescent sensors for amine vapor detection usually suffer from aggregation-caused quenching (ACQ) effect and need to be dispersed in solution or matrix materials. Herein, based on the fluorogen of 2-(2-hydroxyphenyl)quinazolin-4(3H)-one (HPQ) with aggregation-induced emission (AIE) properties, we have developed a fluorescent sensor HPQ-Ac for light-up detection of amine vapors through aminolysis reaction. The portable HPQ-Ac sensor can be easily prepared by directly depositing on filter paper, and it can only light up via exposure to amine vapors among various volatile organic compounds. Taking advantage of its portability and high sensitivity for amine vapors, HPQ-Ac sensor can also be used for food spoilage detection and fluorescent invisible ink.Keywords: aggregation-induced emission; amine vapors; fluorescent sensor; light-up detection

Aromatic alkynes and azides were successfully polymerized under metal-free conditions using tetramethylammonium hydroxide (NMe4OH) as an organocatalyst at room temperature and soluble 1,5-regioregular polytriazoles P3a–P3e with high molecular weights (Mw up to 56000) were readily produced in high yields (up to 96%).

Multifunctional hyperbranched polymers have found wide applications in diverse areas. However, the preparation of these polymers is generally under harsh polymerization conditions with limited reactions. In this work, we prepared multifunctional hyperbranched poly(vinylene sulfide)s (hb-PVSs) by our established efficient and spontaneous thiol–yne click polymerization for the first time. A series of hb-PVSs with high molecular weights (Mw up to 63100) were obtained in high yields (up to 86%) from the polymerizations of monomers 1 and 2 with equivalent molar ratio in THF at 20 °C for 2 h. All the hb-PVSs are regioregular, soluble, and thermally stable. Thanks to the unreacted ethynyl groups on their peripheries, the hb-PVSs could be facilely functionalized by consecutive thiol–yne click reactions. Moreover, the solid films of hb-PVSs exhibit higher refractive index (RI) values (n > 1.64) than those of traditional optical plastics. The TPE-containing hb-PVS shows unique aggregation-enhanced emission characteristic and its aggregates could be used to detect explosives with superamplification effect. Therefore, this work not only proves the universality of our developed spontaneous thiol–yne click polymerization but also provides a powerful and versatile platform for the preparation of multifunctional sulfur-containing polymers.

Tetraphenylfuran (TPF) and its control molecule tetraphenylthiophene (TPT), which are structurally similar to the aggregation-induced emission (AIE) active 2,3,4,5-tetraphenylsilole, were synthesized. Surprisingly, investigation of its photo-physical properties showed that TPF exhibits the aggregation-caused quenching effect instead of AIE characteristics, whereas TPT exhibits a quite weak AIE effect. Combining experimental results and theoretical calculations, this phenomenon was concluded to be co-caused by the restriction of intramolecular rotation (RIR), the mechanism of AIE, and the conjugation effect. Thus, this work provides an insight into RIR, which will greatly promote the development of AIE.

Heparin is a widely used anticoagulant and the quantification of heparin concentration is pivotal for clinical use. However, previous fluorescent probes for heparin detection are usually based on fluorophores with aggregation-caused quenching (ACQ) properties, which severely restrict their applications for quantitative measurement of heparin in a wide range. Herein, we develop an aggregation-induced emission (AIE) probe HPQ-TBP-I for light up detection of heparin based on the electrostatic interaction-triggered formation of the HPQ-TBP/heparin complex and simultaneous displacement of the fluorescence quencher iodide ion. A linear relationship from 0 to 14 μM of heparin accompanied with a low detection limit of 22 nM was achieved, which fully covers the whole clinical dose range (1.7–10 μM). It is anticipated that this easily accessible and sensitive AIE probe is promising for clinical applications.

Aggregation-induced emission (AIE) is a unique photo-physical phenomenon and has become an emerging and hot research area. With the enthusiastic efforts paid by researchers, hundreds of AIE-active luminogens (AIEgens) have been generated but heterocyclic AIEgens are rarely reported. Recently, we enriched the family of AIEgens and reported a pyrazine-based AIEgen of tetraphenylpyrazine (TPP), which could be facilely functionalized by a post-synthetic strategy. In this work, we further expanded the TPP-based AIE system by covalently attaching one, two or four electron-donating triphenylamine moieties to the TPP core via Suzuki coupling, and TPP–TPA, TPP–2TPA and TPP–4TPA were produced, respectively. Thanks to their donor-π-acceptor structures, these luminogens exhibit multi-functional properties, such as excellent thermal stability (up to 504 °C), large molar absorptivity, bright emission in the solid state (quantum yields up to 35.2%), solvatochromism, and high two-photon absorption cross-sections (up to 480 GM). Furthermore, using TPP–TPA as the emitting layer, a triple-layer device was fabricated and a turn-on voltage, maximum luminance, current efficiency, power efficiency, and external quantum efficiency of 3.7 V, 17459 cd m−2, 5.49 cd A−1, 3.18 lm W−1 and 2.88% were realized, respectively. These results indicate a huge potential to develop high-tech applications based on these TPP-based AIEgens.

Correction for ‘Light up detection of heparin based on aggregation-induced emission and synergistic counter ion displacement’ by Shiwu Li et al., Chem. Commun., 2017, 53, 4795–4798

Lipid droplets (LDs) as dynamic organelles are associated with many metabolic processes. Ideal fluorescent probes for LD-specific imaging require excellent specificity, superior brightness, fast cell permeability, and easy preparation. However, conventional fluorophores for LD imaging suffer from drawbacks of aggregation-caused quenching (ACQ), poor photostability, and difficulty of preparation. To tackle these challenges, herein, we develop an easily accessible aggregation-induced emission (AIE) fluorescent probe for LD-specific imaging and dynamic movement tracking. This AIE probe has significant advantages in terms of fast cell permeability, low cytotoxicity, strong photostability, and high two-photon absorption cross-sections in the near infra-red (NIR) range. It is thus expected to have broad applications in the study of LDs' biological functions.

Luminescent materials without conventional aromatic groups have attracted extensive attention in recent years. However, the luminescence mechanism has been obscure and debatable. In the present study, based on oligo(maleic anhydride)s (OMAhs), alternative polymer of poly[(maleic anhydride)-alt-(2,4,4-trimethyl-1-pentene)] (PMP) and copolymers containing different ratios of OMAhs, we have proposed that the luminescence of OMAhs stems from the cluster. Moreover, a mechanism of clusteroluminescence was studied in detail with the assistance of theoretical simulation, which attributed the phenomenon to the intra- and inter-chain n → π* interaction of carbonyl groups of SAh units in OMAhs. Thus, the proposed study will give insights into designing luminescent materials with nonconventional groups.

Photoactivatable probes for lipid droplets (LDs)-specific live-cell imaging are powerful tools for investigating their biological functions through precise spatial and temporal control. Ideal photoactivatable probes for LDs imaging require high concentration accumulation of fluorophores in LDs, simple synthetic procedures, and excellent photoactivation efficiency. However, it is difficult to overcome these challenges by conventional fluorophores due to aggregation-caused quenching (ACQ). In this study, a new class of photoactivatable and LDs-specific fluorescent probes was developed based on dihydro-2-azafluorenones, which can easily undergo photooxidative dehydrogenation reaction to afford 2-azafluorenones with aggregation-induced emission (AIE) properties. Dihydro-2-azafluorenones as photoactivatable and LDs-specific probes display significant advantages of excellent photoactivation efficiency and lack of self-quenching in the aggregated state, and are expected to have broad applications in study of biological functions of LDs' through light-controlled spatiotemporal imaging.