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Herein, we realized the quick generation of stable photoinduced radicals in donor–acceptor triarylphosphines with associated color changes of emission and absorption, which was deciphered by the electron paramagnetic resonance (EPR) spectra.

Stable organic radicals are promising materials for information storage, molecular magnetism, electronic devices, and biological probes. Many organic radicals have been prepared, but most are non- ...

Boosting the circularly polarized luminescence of small organic molecules has been a stubborn challenge because of weak structure rigidity and dynamic molecular motions. To investigate and eliminate these factors, here, we carried out the struc-ture-property relationship studies on a newly-developed axial chiral scaffold of bidibenzo[b,d]furan. The molecular rigidity was finely tuned by gradually reducing the alkyl-chain length. The environmental factors were considered in solution, crystal, and polymer matrix at different temperatures. As a result, a significant amplification of the dissymmetry factor glum from 10-4 to 10-1 with a 146-fold magnification was achieved, corresponding to the situation from (R)-4C in solution to (R)-1C in polymer film at room temperature. A synergistic strategy of increasing the intramolecular rigidity and enhancing the inter-molecular interaction to restrict the molecular motions was thus proposed to improve circularly polarized luminescence. The though-out demonstrated relationship will be of great importance for the development of high-performance small organic chiroptical systems in the future.

Cells are responsive to the mechanical environment, but the methods to detect simultaneously how different organelles react in mechanobiological processes remain largely unexplored. We herein report a dual organelle-targeting fluorescent probe, ( E )-1-[3-(diethoxyphosphoryl)propyl]-4-[4-(diethylamino)styryl]pyridin-1-ium bromide (ASP-PE), for mechanical mapping in live cells. ASP-PE is aggregation-induced emission active and is sensitive to the local mechanical environment. It targets the plasma membrane (PM) and intracellular mitochondria in cells by its phosphonate moiety and pyridinium. In this work, through ASP-PE staining, changes of membrane tension in the PM and mitochondria in response to varied osmotic pressure and substrate stiffness are visualized using fluorescence lifetime imaging microscopy. The mechanobiological importance of actin filaments and microtubules in the PM and mitochondria is also investigated using this probe. Computational simulations are applied to study the sensing mechanism of the probe. This study introduces a unique tool for mapping the membrane tension in the PM and mitochondria together, providing us great opportunities to study organelle’s interactions in mechanobiology.

The construction of molecular chirality is crucial for exploring novel luminophores with chiroptical properties. Classic asymmetric synthesis of chiral center or axial is not powerful enough on through-space architecture. Accessible methodologies for breaking molecular symmetry could be promising but remain less investigated. Herein, we report a novel methodology for constructing chiral through-space luminophores via simple chlorination on bridged carbazole motifs. The chlorination breaks the molecular symmetry and thus results in molecular chirality by eliminating the mirror plane or rotating axis. Interestingly, continuous multiple chlorinations can rebuild and break the symmetry of the skeleton in succession. Several chiral and achiral isomeric analogues are synthesized and characterized with impressive chiroptical properties. Results of chiral HPLC, single-crystal X-ray diffraction, kinetic racemization, and chiroptical property investigation demonstrate the effectiveness of our rational design strategy. It provides a feasible methodology for exploring novel chiral luminescent materials based on versatile though-space skeletons.

Herein, we report a simple approach to generate stableluminescent radicals in the presence of gentle UV irradiation. The newly generated radicalspecies are capable of emitting unusual red light with a maximum fluorescence quantumefficiency of 4.6% at ambient conditions in the solid state. Additionally, the luminescentradicals show extraordinary stability with more than one-year life-span at ambient conditions.X-ray diffraction study combined with photophysical and computational analyses reveal thatthe unique molecular symmetry breaking in the crystalline state lead to the unusual formationand stabilization of radical ion pairs via the photo-induced electron transfer (PET) process. Suchresults represent the first time to achieve stable emissive radicals in the solid state at ambientconditions via in-situ PET process.

Background The current debate over the optimal Enoxaparin prophylactic dosing strategies in obese patients centre around whether it should be based on the actual weight of the patient (i.e. weight-based), or at an artificially fixed amount, as it is the case in Australia (40 mg daily). The vast majority of the evidence available today is laboratory-based, measuring serum Antifactor-X a activities as a marker for physiological response. Aim The aim of the parent study is to compare the clinical outcomes for obese patients who received fixed doses of enoxaparin compared to those who received weight-based doses within the licensed dosage recommendations. This review was conducted to examine whether a gap in knowledge exists in relation to dosing obese patients with enoxaparin as VTE prophylaxis after hospital admission to aid in development of the parent study concept. Method Databases such as Medline, EBSCOhost, ProQuest were interrogated using combinations of words such as “enoxaparin”, AND “dosing strategy”, AND “obese/obesity” AND “prophylaxis”. Only eleven out of 14 primary studies which were considered to be sufficiently similar in methodology and anticipated outcomes were reviewed and analysed. Results Pooled data from the eleven studies suggested that weight-based or higher-than-fixed dosing had a 36.2% higher success rate than fixed dosing, and was more likely to achieve the desired serum Anti-X a activity levels (52.2% and 16% respectively). The rate of failure to achieve this is significantly lower in the weight-based groups (13.3%) than in fixed-dose groups (18.5%). These eleven studies reviewed included 601 patients in total. Conclusion There is insufficient evidence to support or negate the current enoxaparin health outcomes in obese and very obese patients due to the lack of post-discharge follow-up from hospitals. Further research is required to compare long-term outcomes after fixed and weight-based dosing of enoxaparin. The optimal dose of enoxaparin per kilogram of body weight for prophylaxis remains to be determined.

Because of their innate ability to store and then release energy, long persistent luminescence (LPL) materials have garnered strong research interest in a wide range of multidisciplinary fields, such as biomedical sciences, theranostics, and photonic devices. Although many inorganic LPL systems with afterglow durations of up to hours and days have been reported, organic LPL (OLPL) systems have had difficulties reaching similar timescales. We propose in this work a design principle based on the successes of inorganic systems to produce an OLPL system through the use of a strong organic electron trap. The resulting system generated detectable afterglow for up to 7 hours, significantly longer than any other reported OLPL system. The design strategy demonstrates an easy methodology to develop organic long persistent phosphors, opening the door to new OLPL materials.

An antibody–AIEgen conjugate is designed and developed as a “turn-on” fluorescent probe for wash-free specific cancer cell imaging. The cetuximab-conjugated AIEgen shows red fluorescence only when it is internalized and accumulated in cancer cells with overexpressed epidermal growth factor receptor through endocytosis. The probe first lights up the lysosomes. After hydrolysis, its residue is accumulated in mitochondria, making them highly emissive with a long cell retention time. Compared with conventional “always-on” fluorescent probes, the antibody–AIEgen conjugate exhibits a very good image contrast during wash-free cancer cell imaging and less interference from normal cells. To the best of our knowledge, this is the first time “turn-on” antibody–AIEgen conjugates have been reported. This new strategy can be further extended to many proteins and water-soluble AIEgens, and many of their potential applications such as real-time tracking of cell dynamics and cancer theranostics will be explored. The present work is expected to inspire more marvellous research in the fields of AIE and cancer imaging.

Summary Manipulation of the emission properties of pure organic room-temperature phosphors through molecular design is attractive but challenging. Tremendous efforts have been made to modulate their aggregation behaviors to suppress nonradiative decay in order to achieve efficient light emission and long lifetimes. However, success has been limited. To attain such a goal, here we present a rational design principle based on intrinsic molecular-structure engineering. Comprehensive investigations on the molecular orbitals revealed that an excited state with hybrid (n,π*) and (π,π*) configurations in appreciable proportion is desired. Tailoring the aromatic subunits in arylphenones can effectively tune the energy level and the orbital feature of the triplet exciton. Our experimental data reveal that a series of full-color pure organic phosphors with a balanced lifetime (up to 0.23 s) and efficiency (up to 36.0%) can be realized under ambient conditions, demonstrating the validity of our instructive design principle.

The development of intelligent materials, in particular those showing the highly sensitive mechanoresponsive luminescence (MRL), is desirable but challenging. Here we report a design strategy for constructing high performance On–Off MRL materials by introducing nitrophenyl groups to molecules with aggregation-induced emission (AIE) characteristic. The on–off methodology employed is based on the control of the intersystem crossing (ISC) process. Experimental and theoretical investigations reveal that the nitrophenyl group effectively opens the nonradiative ISC channel to impart the high sensitivity and contrast On–Off behavior. On the other hand, the twisted AIE luminogen core endows enhanced reversibility and reduces the pressure required for the luminescence switching. Thin films can be readily fabricated from the designed materials to allow versatile applications in optical information recording and haptic sensing. The proposed design strategy thus provides a big step to expand the scope of the unique On–Off MRL family., The development of intelligent materials, in particular those showing the highly sensitive mechanoresponsive luminescence (MRL), remains challenging. Here the authors report a strategy for constructing high performance On-Off MRL materials by introducing nitrophenyl groups to molecules with aggregation-induced emission characteristic.

Herein we reported a new facile one-pot multicomponent sequential polymerization approach for the construction of conjugated nitrogen-substituted polymers. Catalyzed by Pd(PPh3)2Cl2/CuI at room temperature, the coupling-hydroamination polymerizations of 1,2-bis(4-ethynylphenyl)-1,2-diphenylethene, terephthaloyl chloride and secondary aliphatic amines proceeded smoothly in a regioregular and stereoselective manner, furnishing poly(arylene enaminone)s (PAEs) with high molecular weights (Mw up to 34 600) in satisfactory yields (up to 91%). A model compound was elaborately designed and synthesized to verify the chemical structures of the corresponding polymeric products. All the PAEs exhibited good solubility in common organic solvents and were thermally stable with degradation temperatures of up to 313 °C under nitrogen. They possessed good film-forming ability and their thin solid films showed high refractive indices (RI = 1.9318–1.6320) in a wide wavelength region of 400–1000 nm, whose value could be further modulated by UV irradiation. Although the model compound and the PAEs possessed a typical aggregation-induced emission luminogen of tetraphenylethene, they were weakly emissive either in solution or in the aggregated state, due to the photoinduced electron transfer (PET) effect. Their strong emission in the aggregated state could be readily recovered by the blockage of the PET effect through protonation of the amino groups. Thus, this work demonstrated a powerful polymerization tool to access conjugated polymeric materials with pH-responsive properties.

Solid-state photochromism was found in bis(diphenylmethylene)dihydrotetracene, caused by photocyclization of the embedded cis-stilbene motifs., Reported herein is a new class of pure polycyclic hydrocarbon molecules, designed through a novel aggregation-induced emission (AIE) strategy, with unexpected photochromic properties. The restriction of intramolecular motion was found as a comprehensive mechanism for the AIE effect. The photochromism mechanism study revealed that the photocyclization reaction of cis-stilbene, the molecular conformation in the single crystal and the tetracene backbone should contribute to the unique photo behavior. In particular, the fast responsive, photo-reversible and thermo-irreversible photochromic effect facilitated in the solid state opens a new field of aggregation-promoted photochromism.

Photosensitizers are generally treated as key components for photodynamic therapy. In contrast, we herein report an aggregation-induced emission luminogen (AIEgen)-based photosensitizer (TPE-Py-FFGYSA) that can serve as a non-toxic adjuvant to amplify the antitumor efficacy of paclitaxel, a well-known anticancer drug, with a synergistic effect of "0 + 1 > 1". Besides the adjuvant function, TPE-Py-FFGYSA can selectively light up EphA2 protein clusters overexpressed in cancer cells in a fluorescence turn-on mode, by taking advantage of the specific YSA peptide (YSAYPDSVPMMS)-EphA2 protein interaction. The simple incorporation of FFG as a self-assembly-aided unit between AIEgen (TPE-Py) and YSA significantly enhances the fluorescent signal output of TPE-Py when imaging EphA2 clusters in live cancer cells. Cytotoxicity and western blot studies reveal that the reactive oxygen species (ROS) generated by TPE-Py-FFGYSA upon exposure to light do not kill cancer cells, but instead provide an intracellular oxidative environment to help paclitaxel have much better efficacy. This study thus not only extends the application scope of photosensitizers, but also offers a unique theranostic system with the combination of diagnostic imaging and adjuvant antitumor therapy.

A novel dark through-bond energy transfer (DTBET) strategy is proposed and applied as the design strategy to develop ratiometric Hg2+ sensors with high performance. Tetraphenylethene (TPE) derivatives with aggregation-induced emission (AIE) characteristics are selected as dark donors to eliminate emission leakage from the donors. The TBET mechanism has been adopted since it experiences less influence from spectral overlapping than Forster resonance energy transfer (FRET), making it more flexible for developing cassettes with large pseudo-Stokes shifts. In this work, energy transfer from the TPE derivatives (dark donor) to a rhodamine moiety (acceptor) was illustrated through photophysical spectroscopic studies and the energy transfer efficiency (ETE) was found to be up to 99%. In the solution state, no emission from the donors was observed and large pseudo-Stokes shifts were achieved (>280 nm), which are beneficial for biological imaging. Theoretical calculations were performed to gain a deeper mechanistic insight into the DTBET process and the structure-property relationship of the DTBET cassettes. Ratiometric Hg2+ sensors were rationally constructed based on the DTBET mechanism by taking advantage of the intense emission of TPE aggregates. The Hg2+ sensors exhibited well resolved emission peaks. >6000-fold ratiometric fluorescent enhancement is also achieved and the detection limit was found to be as low as 0.3 ppb. This newly proposed DTBET mechanism could be used to develop novel ratiometric sensors for various analytes and AIEgens with DTBET characteristics will have great potential in various areas including light harvesting materials, environmental science, chemical sensing, biological imaging and diagnostics.

A novel dark through-bond energy transfer (DTBET) strategy is proposed and applied as the design strategy to develop ratiometric Hg2+ sensors with high performance., A novel dark through-bond energy transfer (DTBET) strategy is proposed and applied as the design strategy to develop ratiometric Hg2+ sensors with high performance. Tetraphenylethene (TPE) derivatives with aggregation-induced emission (AIE) characteristics are selected as dark donors to eliminate emission leakage from the donors. The TBET mechanism has been adopted since it experiences less influence from spectral overlapping than Förster resonance energy transfer (FRET), making it more flexible for developing cassettes with large pseudo-Stokes shifts. In this work, energy transfer from the TPE derivatives (dark donor) to a rhodamine moiety (acceptor) was illustrated through photophysical spectroscopic studies and the energy transfer efficiency (ETE) was found to be up to 99%. In the solution state, no emission from the donors was observed and large pseudo-Stokes shifts were achieved (>280 nm), which are beneficial for biological imaging. Theoretical calculations were performed to gain a deeper mechanistic insight into the DTBET process and the structure–property relationship of the DTBET cassettes. Ratiometric Hg2+ sensors were rationally constructed based on the DTBET mechanism by taking advantage of the intense emission of TPE aggregates. The Hg2+ sensors exhibited well resolved emission peaks. >6000-fold ratiometric fluorescent enhancement is also achieved and the detection limit was found to be as low as 0.3 ppb. This newly proposed DTBET mechanism could be used to develop novel ratiometric sensors for various analytes and AIEgens with DTBET characteristics will have great potential in various areas including light harvesting materials, environmental science, chemical sensing, biological imaging and diagnostics.

Herein, two novel N-phenylated N-heteroacenes (1 and 2) are reported, along with details of their synthesis, structures, and properties. Compound 1 is a N-hetero analogue of rubrene, but differs from rubrene by having a bent backbone and behaving as an insulator in the solid state owing to the lack of π-π interactions. Compound 2 is a N-hetero analogue of 6,13-diphenylpentacene (DPP) with essentially the same molecular geometry and crystal packing as DPP, but exhibiting a field effect mobility higher than that of DPP by two orders of magnitude.

Conjugated macrocycles can be equipped with interesting functions by having polycyclic aromatic hydrocarbon (PAH) building blocks that are larger than benzene. The building block explored herein is phenanthrene, which is connected with varied linkers leading to new trimeric conjugated macrocycles (1–4). The coronal macrocycle 1, whose π-backbone is a new segment of [6,6]-carbon nanotube, is synthesized from the flat macrocycle 2 by Lewis acid-catalyzed [4 + 2] benzannulation. This suggests a new strategy to synthesize π-extended nanorings from conjugated macrocycles that are more easily accessed. As found from a comparative study with focus on self-assembly and organic semiconductor behavior, flat or nearly flat conjugated macrocycles 2–4 function as p-type organic semiconductors in solution-processed thin film transistors. Their field effect mobility as measured from as-cast films is dependent on their ability of self-aggregation in solution.