As one of the high pathogenic influenza viruses, H1N1 virus easily induces to serious diseases, even leading to death. To date, all detection methods for H1N1 virus had shortcomings, including high equipment cost, time consumption, and etc. Therefore, a novel detection method should be established to achieve more convenient, rapid, and low-cost detection. In this work, an isomer of HPBmN-I with aggregation-induced emission characteristic was firstly synthesized on the basis of our previous reported HPBpN-I. The results showed that HPBmN-I only selectively binds to N1 in the presence of H1, while HPBpN-I can exhibit total fluorescence response to H1 and N1 in H1/N1 mixture. The limited of detection (LOD) of HPBmN-I to N1 was estimated to be 20.82 ng/mL in normal saline (NS) according to the IUPAC-based approach. The simulation calculations based on molecular docking revealed that four HPBmN-I molecules combine well with the hydrophobic cavity of N1 and achieve the fluorescence enhancement due to size matching with each other. The combination of HPBpN-I and HPBmN-I as probes was successfully used to quantitatively detect H1 and N1 in real H1N1 virus. Compared to enzyme-linked immunosorbent assay (ELISA) method, the established method not only showed the same detection accuracy but also had the advantages of real-time, ease of preparation, and low-cost, demonstrating potential market prospects.
Influenza A Virus, H1N1 Subtype , Influenza, Human , Humans , Molecular Docking Simulation , Sensitivity and Specificity , Enzyme-Linked Immunosorbent Assay/methods
Chiral aggregation-induced emission (AIE) molecules have drawn attention for their helical self-assembly and special optical properties. The helical self-assembly of AIE-active chiral non-linear main-chain polymers can produce some desired optical features. In this work, a series of V-shaped chiral AIE-active polyamides P1-C3, P1-C6, P1-C12 and linear P2-C3, P2-C6, bearing n-propyl/hexyl/dodecyl side-chains, based on tetraphenylbutadiene (TPB), were prepared. All target main-chain polymers exhibit distinct AIE characteristics. The polymer P1-C6 with moderate length alkyl chains shows better AIE properties. The V-shaped main-chains and the chiral induction of (1R,2R)-(+)-1,2-cyclohexanediamine in each repeating unit promote the polymer chains display helical conformation, and multiple helical polymer chains induce nano-fibers helicity when the polymer chains aggregate and self-assemble in THF/H2 O mixtures. Simultaneously, the helical conformation polymer chains and helical nano-fibers cause P1-C6 produce strong circular dichroism (CD) signals with positive Cotton effect. Moreover, P1-C6 could also occur fluorescence quenching response to Fe3+ selectively with a low detection limit of 3.48â µmol/L.
Molecular recognition towards peptides and proteins with high affinity by synthetic supramolecular hosts is important but challenging. In this work, we investigate the molecular recognition of the synthetic cucurbit[7]uril (CB[7]) to 17 designed N-terminal Leu-containing tripeptides in aqueous medium by molecular dynamics (MD) simulation and screen out tripeptides with high binding affinity. It is found that, compared to LGG, only the third residue is Arg (R), the binding affinity of CB[7] to LGR reaches nanomolar level with binding equilibrium constant (Ka) of 1.1 × 109 M-1. The CB[7] recognition to the N-terminal Leu-containing tripeptides is highly sequence dependent; whether changing the sequence order (from LGR to LRG) or increasing the sequence length (from LGR to LGGR), Ka decreases by about three orders of magnitude. Interestingly, substituting N-terminal Leu for its isomer Ile, the binding of CB[7] to tripeptides weakens significantly with Ka decreasing by 3-8 orders of magnitude. Thus CB[7] can effectively distinguish N-terminal Leu-containing tripeptides from N-terminal Ile-containing tripeptides. Importantly, we predict that when R is as C-terminus, regardless of N-terminal residue being of aromatic type or Leu, the binding strength is always close to the nanomolar level. Therefore, R can be introduced to rationally design novel peptides with high binding affinity to CB[7] in practical applications.
Imidazoles , Macrocyclic Compounds , Imidazoles/chemistry , Macrocyclic Compounds/chemistry , Peptides/chemistry , Proteins , Bridged-Ring Compounds/chemistry
Multicomponent spiropolymerization (MCSP) provides an efficient synthetic tool for the construction of spiropolymers based on nonspiro monomers. In this study, a method of MCSP using diisocyanides 1, diethyl acetylenedicarboxylate 2, and halogenated quinones 3 is developed for the in situ construction of bis-spiropolymers with high molecular weights (Mw up to 29 200) and good yields (up to 87.7%) under mild reaction conditions. The structure of the obtained bis-spiropolymers is confirmed by gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance analysis. Halogenated bis-spiropolymers show good thermal stability, good solubility, and film-forming ability. The photosensitizer rhodamine B is used as a doping agent to induce the photodegradation of the polymer P1a3c into small-molecule segments, which results in the slow release of halogenated spiro-groups under irradiation with simulated sunlight. This finding reveals that P1a3c has the potential to be applied in pesticides. Therefore, this MCSP is a novel method for preparing halogen-containing bis-spiropolymers, which accelerates the development of multifunctional polymer materials.
Alkynes , Quinones , Photolysis , Polymers , Spectroscopy, Fourier Transform Infrared
Polymers containing iminofuran (PIFs) are rarely reported due to the lack of simple and effective synthesis methods. In this work, a novel multicomponent cyclopolymerization (MCCP) of diisocyanides, activated alkynes, and 1,4-dibromo-2,3-butanedione using catalyst-free one-pot reactions under mild conditions to prepare PIFs containing bromomethyl groups is reported. PIFs with good solubility and thermal stability are obtained with high Mw s (up to 19 600) and good yields (up to 89.5%) under optimized polymerization conditions. The structure of the PIFs is characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, and gel permeation chromatography. The photophysical properties indicate that polymers P1a2b3 and P1c2b3 have cluster-triggered emission characteristics. Thin films made from PIFs quickly degrade under UV irradiation. Moreover, the obtained polymers are decorated with bromomethyl and carboxylate groups in the side chain, which can be postfunctionalized to prepare multifunctional materials, such as star branched polymers and biomedical carrier materials. Thus, this work not only enriches the field of polymerization based on isocyanates and activated alkynes but also provides a facile strategy toward functional iminofuran polymers.
Alkynes , Diacetyl , Catalysis , Polymerization , Polymers
AIE-active positional isomers, TTE-o-PhCHO, TTE-m-PhCHO and TTE-p-PhCHO, tetrathienylethene (TTE) derivates with peripherally attached ortho-/meta-/para-formyl phenyl groups, were designed and synthesized. The formyl substitution position can effectively modulate their photophysical properties, mechanochromism and fluorescent response to hydrazine. TTE-o-PhCHO and TTE-m-PhCHO exhibit remarkable AIE characteristics, and TTE-p-PhCHO possesses aggregation-induced emission enhancement performance. They all exhibit high contrast mechanochromism, and TTE-m-PhCHO shows larger red-shift (164â nm) than TTE-o-PhCHO (104â nm) and TTE-p-PhCHO (125â nm) due to the more twisted molecular conformation and much looser molecular packing. Moreover, TTE-o-PhCHO with a higher contrast color change can be used as ink-free rewritable paper. In addition, TTE-p-PhCHO, as a turn-on fluorescent probe, can selectively detect hydrazine with significant color changes that are visible by the naked eye . Therefore, the position dependence of groups would be an effective method to modulate the molecular arrangement, as well as develop AIE compounds for mechano-stimuli responsive materials, ink-free rewritable papers and chemosensors.
Five organic luminophores, 1,2,5-triphenylpyrrole (TPP) derivatives 3 a-e bearing electron-withdrawing or electron-donating groups, have been synthesized by Pd-catalyzed Suzuki coupling of 1-phenyl-2,5-di(4'-bromophenyl)pyrrole and para-substituted phenylboronic acid derivatives. They possess good thermal stabilities with high decomposition temperatures above 310 °C. Investigation of the photophysical properties of the luminogens 3 a-e indicated that they exhibited dual intense photoluminescence in both solution and the solid state due to their twisted conformations, and their fluorescence quantum yields (ΦF ) were determined as 68.7-94.9 % in THF solution and 19.1-52.0 % in solid powder form. Compounds 3 a-c bearing electron-accepting groups exhibited remarkable solvatochromism with large Stokes shifts, attributable to their D-π-A structure and intramolecular charge-transfer effect. In particular, 3 a, bearing aldehyde groups, displayed an obvious red-shift of the emission band from 445 to 564â nm with increasing solvent polarity. However, no obvious solvatochromic behavior was observed for compounds 3 d,e bearing electron-donating groups. The luminophore 3 a exhibited polymorphic luminescence properties and crystallization-induced emission enhancement.
2,3,4,5-Tetraphenyl-1H-pyrrole (TePP) was synthesized by a simple one-step reaction. The compound showed a balanced emission in both the solution and solid state with the absolute quantum yield of ΦF/THF =65.6 % and ΦF/solid =74.3 %, respectively. Temperature and viscosity variation measurements demonstrated that the phenyl group at the 1-position (N-position) of the pyrrole core can act as a rotor in pyrrole-based molecules, which can consume the excited energy and reduce the molecular emission in solution. TePP without the phenyl group at the 1-position can effectively enhance the emission in solution. Single-crystal analysis showed that the phenyl groups at the 2,5-positions of pyrrole extend the molecular conjugation and lock the conformation. The phenyl groups at the 3,4-positions with a twisted conformation prevent their molecules from close packing and are helpful for aggregated emission. A delicate balance between the twisting conformation and rigid conjugation takes advantage of both ACQ and AIE luminogens. The strategy can tune the AIE, ACQ, or solution and solid dual-state emission properties of pyrrole-based molecules by simply altering the position of phenyl groups, which provides a great opportunity to explore the luminescent mechanism in greater detail and to facilitate practical applications.
Eight donor-π-acceptor (D-π-A) compounds employing triphenylpyrrole isomers (TPP-1,2,5 and TPP-1,3,4) as donors, malononitrile (CN) and 1H-indene-1,3(2H)-dione (CO) as acceptors, pyridone (P) and benzopyran (B) as π-linking groups were synthesized. The compounds exhibited aggregation-induced emission and piezochromic properties. Compared with previously reported donors, triphenylpyrroles induced all the compounds to have more remarkable photophysical properties. The compounds containing TPP-1,2,5 and P moieties displayed stronger fluorescence intensities, shorter emission wavelengths, and more distinct piezochromic properties. However, the same phenomenon was observed in the TPP-1,3,4-containing system if B was as π-linker. Moreover, the CN acceptor endowed the compound to have a relatively strong fluorescent intensity, in which CO induced a relatively long emission wavelength. That is, the photophysical properties of D-π-A compounds can be controlled by adjusting the structure of donor, linker and acceptor.
A novel fluorescent probe, tris (2-(dimethylamino) ethyl)-4,4',4â³-(1H-pyrrole-1,2,5-triyl) tribenzoate (TPP-TMAE), with aggregation-enhanced emission (AEE) feature showed a simple, highly selective, specific, and instant response to trace amount carbon dioxide (CO2). Because of this special characteristic, TPP-TMAE is ideal to be a biomarker for in-situ monitoring of the CO2 generation rate during the metabolism of single living cell. The rates in single living HeLa cell, MCF-7 cell, and MEF cell were 6.40 × 10(-6)±6.0 × 10(-8) µg/h, 5.78 × 10(-6)±6.0 × 10(-8) µg/h, and 4.27 × 10(-7)±4.0 × 10(-9) µg/h, respectively. The distinct responses of TPP-TMAE to CO2 generated from cancer cells and normal cells suggested TPP-TMAE as a useful tool for deeper understanding metabolism process and distinguishing cancer cells from normal cells during the early diagnosis of cancers.
Biomarkers, Tumor/metabolism , Carbon Dioxide/metabolism , Fluorescent Dyes/chemistry , Molecular Imaging/methods , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/pathology , Carbon Dioxide/chemistry , HeLa Cells , Humans , MCF-7 Cells , Metabolic Clearance Rate , Neoplasms, Experimental/chemistry
A dye emitted red fluorescence with aggregation-enhanced emission properties was reported here. It can be utilized to specifically recognize the cell membrane of MCF-7 and 293T cell lines during bio-imaging.
Cell Membrane/metabolism , Fluorescent Dyes/chemistry , Fluorescent Dyes/pharmacology , Pyrroles/chemistry , Pyrroles/pharmacology , HEK293 Cells , Humans , MCF-7 Cells , Microscopy, Confocal
Three tetra-aryl substituted 1,3-butadiene derivatives with aggregation enhanced emission (AEE) and mechanochromic fluorescence behavior have been rationally designed and synthesized. The results suggest an effective design strategy for developing diverse materials with aggregation induced emission (AIE) and significant mechanochromic performance by employing D-π-A structures with large dipole moments.
Reversible piezochromic luminescence and aggregation induced emission properties of 4,4'-((Z,Z)-1,4-diphenylbuta-1,3-diene-1,4-diyl)dibenzoic acid are reported. The photoluminescent color of it changes from blue to yellow-green upon grinding, which can be restored upon exposure to a solvent. Intermolecular hydrogen bonding plays a key role in the altered emission.
Fully conjugated metallosupramolecular self-assembled multilayer films were controllably fabricated based on bibenzonitril-phthalocyaninato ruthenium(II) (BBPR) and 4,4'-bipyridine (BP) via axially coordination interaction between ruthenium ions and the pyridine groups on the modified substrates. The substrates were first functionalized by 4-(pyridine-4-ylethynyl)benzenic diazonium salt (PBD) through photodecomposition of diazonium group under UV irradiation. As a result, the pyridine-containing functional groups were vertically and covalently anchored onto the surface of substrate and got a stable monolayer. Soluble ruthenium phthalocyanine, axially coordinated by labile benzonitrile groups, was used to fabricate the layer-by-layer self-assembled films with BP through ligand-exchanging reaction between benzonitrile and pyridine in each self-assembled cycle. The UV-vis analysis results demonstrated the successful fabrication of bi(4,4'-bipyridine)phthalocyaninato ruthenium(II) (BPPR) metallosupramolecular ultrathin films with definite structures on PBD-modified substrate. Under illumination, the BPPR self-assembled multilayer films displayed a quick response to light. The maximum current density reached 120 nA/cm(2) at six bilayers. The Eg, HOMO, and LUMO of the six-bilayer were quantitatively measured to be 1.68, -5.29, and -3.61 eV, respectively. This strategy supplies a facile method to get full-conjugated metallosupramolecules and a platform for developing higher performance solar cell from the point of adjusting dye aggregate state structure.
A water-soluble, 'turn-on' fluorescent chemosensor based on aggregation-induced emission (AIE) has been developed. It exhibits rapid response, excellent selectivity, and sensitivity to Al(3+).
Aluminum/analysis , Fluorescent Dyes/chemistry , Spectrometry, Fluorescence , Ions/chemistry , Water/chemistry
The relationship between the structures and light emission properties of five aryl-substituted pyrrole derivatives was studied during aggregation in THF-water mixtures. Only pentaphenylpyrrole clearly shows, however, an aggregation-induced emission enhancement (AIEE) phenomenon. On comparison of the optical properties and single-crystal structures of these pyrrole derivatives, it is suggested that the more twisted configuration which prevented parallel orientation of conjugated chromophores combined with the restricted intramolecular rotation (RIR) effect was the main cause of the AIEE phenomenon.
4-(2-(4-pyridinyl)Ethynyl)benzenic diazonium salt (PBD) was used to modify multiwalled carbon nanotubes (MWCNTs) by the self-assembly technique. After the decomposition of the diazonium group in PBD under UV irradiation, the PBD monolayer film covalently anchored on multiwalled carbon nanotubes is very stable. The obtained pyridine-modified MWCNTs (Py(Ar)-MWCNTs) have good solubility in common organic solvents. Furthermore, the layer-by-layer (LBL) self-assembled fully conjugated films of Py(Ar)-MWCNTs and (phthalocyaninato)ruthenium(II) (RuPc) were fabricated on the PBD-modified substrates, and characterized using UV-vis absorption spectroscopy, scanning electron microscopy (SEM), and electrochemistry. The UV-vis analysis results indicate that the LBL RuPc/Py(Ar)-MWCNTs self-assembled multilayer films with axial ligands between the ruthenium atom and pyridine group were successfully fabricated, and the progressive assembly runs regularly with almost equal amounts of deposition in each cycle. A top view SEM image shows a random and homogeneous distribution of Py(Ar)-MWCNTs over the PBD-modified silicon substrate, which indicates well independence between all Py(Ar)-MWCNTs. Moreover, the opto-electronic conversion was also studied by assembling RuPc/Py(Ar)-MWCNTs multilayer films on PBD-modified ITO substrate. Under illumination, the LBL self-assembled films on ITO showed an effective photoinduced charge transfer because of their conjugated structure and the ITO current density changed with the number of bilayer. As the number of bilayers was increased, the photocurrent increases and reaches its maximum value (â¼300 nA/cm(2)) at nine bilayers. These results allow us to design novel materials for applications in optoelectronic devices by using LBL self-assembly techniques.
1,2,5-triphenylpyrrole (TPP) was firstly prepared by the Schulte-Reisch reaction of 1,4-diphenylbuta-1,3-diyne with aniline catalyzed by copper chloride. Compared to solution reaction in DMF as solvent, the bulk reaction modified in this paper not only increased the yield and reduced the reaction temperature, but also shortend the reaction time. The pi-pi stacking interaction and the restriction of intramolecular rotation are were involved at the same time when TPP was aggregated in the THF-water mixtures. When the water volume fraction was under 60%, the PL intensity of TPP was independent on the water fraction in THF-water mixture. When the water fraction was added to 70%, which induced the non-tight aggregation of TPP, the strong pi-pi stacking interaction toned the nonradiative deactivation process and led to quenching the fluorescence of TPP; if the water fraction was further increased to 80%, which induced the tight aggregation of TPP, the restriction of intramolecular rotation was, however, preponderant over pi-pi stacking interaction. Thus the nonradiative channel was blocked and the photoluminescence intensity of TPP was enhanced. The compact degree of aggregation was influenced by acetonitrile solvent due to the charge transfer interaction between TPP and acetonitrile. The aggregation-induced emission enhancement of TPP in THF-water mixture disappeared in acetonitrile-water mixture.
4-(2-(4-pyridinyl)ethynyl)benzenic diazonium salt (PBD) was synthesized and used to modify the substrate by self-assembly (SA) technique. Following decomposition of the diazonium group in PBD under UV irradiation, the ionic bonds between the diazonium salt and substrate are converted to covalent bonds. The PBD monolayer film anchored on substrates is very stable. Furthermore, the layer-by-layer (LBL) self-assembled films of bis(4,4'-bipyridine)(phthalocyaninato)ruthenium(II) (RuPc(bipy)2, BPR) and triruthenium dodecacarbonyl (Ru3(CO)12, TRDC) were fabricated on the PBD-modified substrates and characterized using UV-vis absorption spectroscopy, atomic force microscopy (AFM), and electrochemistry. The UV-vis analysis results indicate that the LBL TRDC-BPR self-assembled multilayer films with axial ligands between ruthenium atoms and pyridine groups were successfully fabricated and the progressive assembly runs regularly with almost equal amounts of deposition in each cycle. The AFM images of the seven-bilayer TRDC-BPR film on silicon wafer showed round-shaped small domains with sizes of 30-40 nm. The values of the energy band gap (Eg), the highest occupied molecular orbital (HOMO), and the lowest unoccupied molecular orbital (LUMO) of six-bilayer TRDC-BPR on indium-tin-oxide (ITO) glass slides were measured using the UV-vis absorption spectrum and a cyclic voltammogram with values of 1.8, -5.0, and -3.2 eV, respectively. Under illumination, the self-assembled film on ITO showed effective photoinduced charge transfer and changed the current density. As the number of bilayers was increased, the photocurrent increased and reached its maximum value (approximately 150 nA/cm2) at six bilayers. A further increase in the number of bilayers led to a decrease in current due to the increase in cell resistance. The results allow us to design new materials with higher performance for optoelectronic applications.
Whereas aggregation often quenches luminescence, the emission of a heterocyclic luminogen, 10-[2,5-bis(4-pentyloxyphenylcarbonyloxy)phenyl]-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (3), is greatly enhanced by aggregate formation. Crystallization further boosts the emission of 3, turning it from a weak emitter in the solution state to a strong emitter in the crystalline state. The emission of 3 is changed in response to the exposure to vapors of volatile organic compounds (VOCs). The morphology of the thin film of 3 is reversibly and repeatedly modulated between amorphous and crystalline phases by simple fuming-heating and heating-cooling cycles, leading to an emission switching between bright and dark states. The novel attributes of the crystallization-induced emission enhancement, the VOC-responsive emission change, and the morphology-tunable emission switching of 3 could enable it to find applications in an array of technological areas, including chemosensing, optical display, and rewritable information storage.
