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To further explore the candidate materials for latent fingerprints detection, two triphenylamine‐based salicylaldimine compounds containing phenoxazine moiety (TPA‐PXZ) and carbazole unit (TPA‐Cz) were designed and successfully synthesized, respectively. They exhibited intramolecular charge transfer transitions and aggregation‐induced emission properties. Based on quantum chemical calculation results, it was found that compounds TPA‐Cz and TPA‐PXZ had twisted spatial configuration, which were responsible for aggregation‐induced emission. Meanwhile, the morphology of two compounds nano‐aggregates in the THF/water mixtures with 60 % and 80 % water content was tested. To our delight, the developers that prepared by compounds TPA‐Cz and TPA‐PXZ both were used for latent fingerprints detection on the surface of glasses, and they emitted purple fluorescence, as well as the distinct fingerprint imaging could be easily distinguished fingerprint level 1–3 details. We believe that TPA‐Cz and TPA‐PXZ both are the promising candidate for latent fingerprints detection. [ABSTRACT FROM AUTHOR]

Purpose: Fluorescence-guided surgery (FGS) can play a key role in improving radical resection rates by assisting surgeons to gain adequate visualization of malignant tissue intraoperatively. Designed ankyrin repeat proteins (DARPins) possess optimal pharmacokinetic and other properties for in vivo imaging. This study aims to evaluate the preclinical potential of epithelial cell adhesion molecule (EpCAM)-binding DARPins as targeting moieties for near-infrared fluorescence (NIRF) and photoacoustic (PA) imaging of cancer. Methods: EpCAM-binding DARPins Ac2, Ec4.1, and non-binding control DARPin Off7 were conjugated to IRDye 800CW and their binding efficacy was evaluated on EpCAM-positive HT-29 and EpCAM-negative COLO-320 human colon cancer cell lines. Thereafter, NIRF and PA imaging of all three conjugates were performed in HT-29_luc2 tumor-bearing mice. At 24 h post-injection, tumors and organs were resected and tracer biodistributions were analyzed. Results: Ac2-800CW and Ec4.1-800CW specifically bound to HT-29 cells, but not to COLO-320 cells. Next, 6 nmol and 24 h were established as the optimal in vivo dose and imaging time point for both DARPin tracers. At 24 h post-injection, mean tumor-to-background ratios of 2.60 ± 0.3 and 3.1 ± 0.3 were observed for Ac2-800CW and Ec4.1-800CW, respectively, allowing clear tumor delineation using the clinical Artemis NIRF imager. Biodistribution analyses in non-neoplastic tissue solely showed high fluorescence signal in the liver and kidney, which reflects the clearance of the DARPin tracers. Conclusion: Our encouraging results show that EpCAM-binding DARPins are a promising class of targeting moieties for pan-carcinoma targeting, providing clear tumor delineation at 24 h post-injection. The work described provides the preclinical foundation for DARPin-based bimodal NIRF/PA imaging of cancer. [ABSTRACT FROM AUTHOR]

A new thermally stable chromophore exhibiting the intense blue fluorescence with the high quantum yield of 91%, 4-(4-(9H-carbazol-9-yl)phenyl)-2,6-bis-(4-N,N-diphenyl-aminophenyl)pyridine, was synthesized in a high yield via the three-component reaction of 4-(N,N-dimethylamino)acetophenone, 4-(9H-carbazol-9-yl)benzaldehyde, and ammonium acetate. [ABSTRACT FROM AUTHOR]

A novel fluorogenic alkyl diazirine photocrosslinker bearing an o‐hydroxycinnamate moiety has been developed for identification of the targets of bioactive molecules. The o‐hydroxycinnamate moiety can be converted to the corresponding 7‐hydroxycoumarin derivative, which should be created on the interacting site within the photocaptured target protein. The label yield and fluorescence intensity have been immensely improved in comparison with our previous aromatic crosslinkers to facilitate target identification in small quantities. [ABSTRACT FROM AUTHOR]

A water‐soluble hydrazone ligand bearing 2‐nicotinoylhydrazineylidene moiety, sodium 4‐hydroxy‐3‐([2‐nicotinoylhydrazineylidene]methyl) benzenesulfonate (NaH2NH), and its complexes with Co(II), Fe(III), and Mn(II) have been synthesized and characterized. The structure of the ligand and its complexes were analyzed using various spectroscopic techniques such as FT‐IR, 1H‐ and 13C‐NMR, EI‐mass, powder X‐ray diffraction, UV–visible spectra, and magnetic measurements. The infrared spectra indicated that the ligand behaves as a negatively charged bidentate ligand (ON) through the deprotonation of the enolic (OH) group and the azomethine (C=N) group in the [Co (NaHNH)2(H2O)4Cl2].3H2O complex. In the [Fe (NaNH)2(H2O)Cl].2H2O complex, the ligand behaves as bi‐negative tetradentate (O2N2) through the protonation of the enolic oxygen and the nitrogen atom of the azomethine group in two nicotinic hydrazone molecules. Another coordination type was observed for [Mn (NaNH)(H2O)3] complex in which NaH2NH acts as bi‐negative tridentate ONO through the nitrogen atom of the azomethine group, the protonated of enolic and phenolic groups. The fluorescence spectrum of the NaH2NH was found to be quenched upon addition of these Co(II) and Mn(II) ions. The antimicrobial results indicated that the Mn(II) complex exhibited the highest antibacterial potency against all targeted organisms. The results of antioxidants demonstrated that the complexes exhibited higher activity compared to the free ligand, indicating an enhancement of antioxidant activity through complexation. The tested substances established strong nuclease‐like activity at a high concentration of 7.5 mM, leading to the complete degradation of DNA as observed in agarose gel electrophoresis. This suggests that these compounds have the potential to serve as antitumor agents in vivo by inhibiting DNA replication in cancer cells and preventing tumor growth. The interaction of the isolated compounds with 1c14 and 6vj3 targets was discussed using molecular docking. [ABSTRACT FROM AUTHOR]

Pd‐catalyzed cyclization of a fluorescent dimer in which two cores of the potent estrogenic estradiol are bridged by the 1,4‐diethynil benzene moiety led to a steroid dimer bearing the 1,4‐di(benzofuran‐2‐yl)benzene. The obtained compound showed an intense blue fluorescence characterized by a broad emission band between 350 and 550 nm, with four maxima at 384, 403, 435, and 456 nm. The benzofuran dimer showed an 18‐fold increased quantum yield compared with that of its synthetic precursor. [ABSTRACT FROM AUTHOR]

An asymmetric aza-BODIPY analogue bearing quinoxaline moiety was synthesized via a titanium tetrachloride-mediated Schiff-base-forming reaction of 6,7-dimethyl-1,4-dihydroquinoxaline-2,3-dione and benzo[d]thiazol-2-amine. This novel aza-BODIPY analogue forms a complementary hydrogen-bonded dimer due to the quinoxaline moiety in the crystal structure. It also shows intense absorption and fluorescence, with fluorescence quantum yields close to unity. The electrochemical measurements and the DFT calculations revealed the presence of the low-lying HOMO, which benefits their potential applications as an electron-transporting material. [ABSTRACT FROM AUTHOR]

A modified 2′‐deoxycytidine triphosphate derivative (dCTOTP) bearing a thiazole orange moiety tethered via an oligoethylene glycol linker was designed and synthesized. The nucleotide was incorporated into DNA by DNA polymerases in vitro as well as in live cells. Upon incorporation of dCTOTP into DNA, the thiazole orange moiety exhibited a fluorescence lifetime that differed significantly from the non‐incorporated (i.e. free and non‐covalently intercalated) forms of dCTOTP. When dCTOTP was delivered into live U‐2 OS cells using a synthetic nucleoside triphosphate transporter, it allowed us to distinguish and monitor cells that were actively synthesizing DNA in real time, from the very first moments after the treatment. We anticipate that this probe could be used to study chromatin organization and dynamics. [ABSTRACT FROM AUTHOR]

Phosphonium‐based compounds gain attention as promising photofunctional materials. As a contribution to the emerging field, we present a series of donor‐acceptor ionic dyes, which were constructed by tailoring phosphonium (A) and extended π‐NR2 (D) fragments to an anthracene framework. The alteration of the π‐spacer of electron‐donating substituents in species with terminal −+PPh2Me groups exhibits a long absorption wavelength up to λabs=527 nm in dichloromethane and shifted the emission to the near‐infrared (NIR) region (λ=805 nm for thienyl aniline donor), although at low quantum yield (Φ<0.01). In turn, the introduction of a P‐heterocyclic acceptor substantially narrowed the optical bandgap and improved the efficiency of fluorescence. In particular, the phospha‐spiro moiety allowed to attain NIR emission (797 nm in dichloromethane) with fluorescence efficiency as high as Φ=0.12. The electron‐accepting property of the phospha‐spiro constituent outperformed that of the monocyclic and terminal phosphonium counterparts, illustrating a promising direction in the design of novel charge‐transfer chromophores. [ABSTRACT FROM AUTHOR]

The application of coumarin probes as chemosensors for the detection of various species has been broadly explored in recent ages because of their exclusive optical photophysical presentation. The present review especially emphasizes the mechanism involved in the recognition of various vital species through coumarin probes and highlights the current developments in the design of such types of coumarin chemosensors. We also draw attention to the application of the concern protocol and shortfalls of reported coumarin‐based fluorescent probes and express our standpoint on future progress in this arena. We are optimistic that the present review can be explored not only as a reference guide for novices but conjointly as a compass of these fields and contribute to cracking more brilliant and meaningful moieties for biological and chemical researchers. [ABSTRACT FROM AUTHOR]

Through McMurry coupling reaction, three meso‐position functionalized pillar[5]arene derivatives (H‐1, H‐2, and H‐3) have been successfully prepared by embedding aggregation‐induced emission luminogens (AIEgens, diphenyldibenzofulvene (DPDBF) and tetraphenylethylene (TPE)) into the skeleton of supramolecular macrocycles. H‐1, bearing [15]paracyclophane ([15]PCP) and DPDBF moiety, exhibits yellow emission and demonstrates obvious AIE effect. In order to further improve the host‐guest properties of this type of structure, H‐2 and H‐3 are prepared by replacing the [15]PCP moiety with pillar[5]arene backbone, both of which show significant AIE effect and excellent host‐guest complexation properties with pyrazine salt guest G‐1 and 1,4‐dicyanobutane G‐2. Our findings indicate that G‐1 can decrease the fluorescence intensity of the AIE macrocycles, while G‐2 can increase their fluorescence intensity in solution. [ABSTRACT FROM AUTHOR]

In this review, recent advances that exploit the intrinsic emission of organic materials for reversibly modulating their intensity with applied potential are surveyed. Key design strategies that have been adopted during the past five years for developing such electrofluorochromic materials are presented, focusing on molecular fluorophores that are coupled with redox-active moieties, intrinsically electroactive molecular fluorophores, and unconjugated emissive organic polymers. The structural effects, main challenges, and strides toward addressing the limitations of emerging fluorescent materials that are electrochemically responsive are surveyed, along with how these can be adapted for their use in electrofluorochromic devices. [ABSTRACT FROM AUTHOR]

The synthesis of a variety of polyazamacrocyclic compounds comprising structural units of tris(3-aminopropyl)amine (TRPN) and oxadiamines, decorated with one or two fluorophore groups (dansyl or quinoline) at different nitrogen atoms, was carried out using Pd(0)-catalyzed amination. The dependence of the yields of the macrocycles on the synthetic path was observed. The spectrophotometric and fluorescent properties of the target compounds were studied, and their coordination with metal cations using UV–vis, fluorescence spectra as well as NMR titration was investigated. The stoichiometry and binding constants of several complexes with Cu(II), Zn(II), Cd(II), Pb(II) and Hg(II) were established. Three of the six studied macrocycles can be judged as prospective detectors of Zn(II) cations due to the substantial enhancement of fluorescence. [ABSTRACT FROM AUTHOR]

(1,6)Pyrenophanes 1 and 2 in which 1,6-positions of pyrene are bridged with respective tri- and tetra-ethylene glycol chains were synthesized. Addition of Ba(ClO4)2 to a 10−5 M CH2Cl2 : CH3CN = 1 : 1 solution of 1 reduced the intramolecular excimer emission with a maximum at 480 nm and increased the monomer emission around 370–400 nm. In contrast, addition of Ba(ClO4)2 to the solution of 2 shifted the intramolecular excimer emission to shorter wavelengths. Addition of n-Bu2NH2+PF6− to the solutions of 1 and 2 both decreased the intramolecular excimer emission and increased the monomer emission. Based on the results of these fluorescence changes, Job's plots, and NMR titration, it is concluded that 1 forms a 1 : 1 sandwich-type complex with Ba2+, 2 forms a 1 : 2 dumbbell-type complex with Ba2+, and both 1 and 2 form pseudorotaxanes with n-Bu2NH2+. It was also found that when the pyrenophanes 1 and 2 were mixed with tetracyanoethylene (TCNE) in CH2Cl2, charge-transfer (CT) complexes were formed, that exhibited absorption maxima at 740 and 744 nm, respectively. [ABSTRACT FROM AUTHOR]

Multistimuli‐responsive chromism was observed for vinylene‐linked bisflavin 1 a with an extended π‐conjugated platform. The yellow emission of a dilute solution of 1 a in CHCl3 (0.2 mM) observed at 298 K under UV excitation was changed to orange or red emission upon (1) an increase of concentration, (2) a decrease of temperature, and (3) variation of the solvent. This is in contrast to the almost non stimuli‐responsive chromism of the N‐methylated bisflavin analogue 1 b and monoflavin 2 a. Mechanistic investigation by 1H NMR analysis under various conditions revealed that the extended π‐conjugation platform and imide moiety of 1 a generate controllability in the formation of lower‐ and higher‐ordered aggregates, which induce variation of the emission color upon change. Bisflavin 1 a also exhibited redox‐induced chromism, where the orange emission of 1 a was quenched by the addition of hydrazine under anaerobic conditions, and changed back to the original emission upon subsequent bubbling of O2 gas. [ABSTRACT FROM AUTHOR]

Synthetic approach to fluorescent polyaza- and polyoxadiazamacrocycles comprising a structural fragment of 6,7-diamino-2,3-diphenylquinoxaline has been elaborated using Pd-catalyzed amination providing target compounds in yields up to 77%. A series of nine novel N- and N,O-containing macrocyclic ligands differing by the number of donor sites and cavity size has been obtained. These compounds possess well-pronounced fluorescent properties with emission maxima in a blue region in aprotic solvents and high quantum yields of fluorescence, while in proton media, fluorescence shifts towards the green region of the spectrum. Using macrocycles 5c and 5e as examples, we have shown that such compounds can serve as dual-channel (colorimetric and fluorimetric) pH indicators in water media, with pH transition point and response being dependent on the macrocycle structure due to different sequences of protonation steps. [ABSTRACT FROM AUTHOR]

Five random copolymers comprising styrene and styrene with pendant fluorophore moieties, namely pyrene, naphthalene, phenanthrene, and triphenylamine, in molar ratios of 10:1, were synthesized and employed as fluorescent sensors. Their photophysical properties were investigated using absorption and emission spectral analyses in dichloromethane solution and in solid state. All copolymers possessed relative quantum yields up to 0.3 in solution and absolute quantum yields up to 0.93 in solid state, depending on their fluorophore components. Fluorescence studies showed that the emission of these copolymers is highly sensitive towards various nitroaromatic compounds, both in solution and in the vapor phase. The detection limits of these fluorophores for nitroaromatic compounds in dichloromethane solution proved to be in the range of 10−6 to 10−7 mol/L. The sensor materials for new hand-made sniffers based on these fluorophores were prepared by electrospinning and applied for the reliable detection of nitrobenzene vapors at 1 ppm in less than 5 min. [ABSTRACT FROM AUTHOR]

Apart from being the unit of proteins, amino acids have diverse roles. Here we have shown that amino acids guide the differential transportation of a dye molecule to the cellular organelles depending upon the property of their intrinsic functionality. We have conjugated the nitrobenzofurazan (NBD) moiety with two amino acids (lysine and histidine derivatives) with a linker. Both derivates are water‐soluble and biocompatible in nature. Surprisingly, we found that lysine‐conjugated NBD (NBD‐Lys) stains lipid droplets whereas histidine‐conjugated NBD (NBD‐His) stains lysosomes. We also measured the spectral properties of these two NBD conjugates. The results depict that both conjugates are extremely stable both in air and under inert atmosphere, and the fluorescence of the derivatives remains almost unaltered at different pH. Further by altering the functionality of the side chain, we established the contribution of each functional group towards this differential organelle targeting. [ABSTRACT FROM AUTHOR]

The reaction of fluorescein-substituted 2-hydroxybenzaldehyde with 3H-indolium perchlorate has led to the formation of 1,3-dihydrospiro[indole-2,2′-chromene] bearing a fluorescein fragment at position 8 of chromene. In a solution, the obtained compound has existed in the cyclic form and has exhibited photochromic properties. Adding transition metal perchlorates to the spiropyran solution has led to intense coloration due to the complex formation. Zinc and cadmium complexes of the spiropyran have exhibited red fluorescence and negative photochromism. [ABSTRACT FROM AUTHOR]

We report a series of (Z)-5-(4-hydroxybenzylidene)-2-thioxothiazolidin-4-ones containing halogens at different positions of the benzylidene moiety. The new compounds exhibit fluorogenic properties and form fluorescent complexes with FAST. We showed that 3-halogen-4-hydroxybenzyliden-rhodanines can be used as ligands for the fluorogen-activating protein FAST in fluorescence microscopy. [ABSTRACT FROM AUTHOR]

Herein, two poly(3-aminocarbazole) derivatives containing imidazole N -type acceptor were synthesized and reported, which are named PCPI and PCBI respectively. The fluorescence spectrum shows that PCPI (Em = 498 nm) and PCBI (Em = 398 nm) both have a strong fluorescence emission. It is worth noting that PCPI has a larger stokes shift of 153 nm, which is beneficial for improving the sensitivity of the sensor and enhancing its anti-interference ability. As expected, our experimental results indicate that both PCPI and PCBI can cause a specific response of "fluorescence OFF" to Hg2+ compared with other ions. And PCPI and PCBI both have excellent detection capabilities for Hg2+, with detection limits of 69.8 nM and 11.4 nM respectively. Moreover, PCBI exhibits excellent absorption of Hg2+ with a maximum absorption capacity of 477.8 mg/g at 20 °C. It indicates that PCBI can be used as a functional material for the detection and removal of Hg2+ in water. The mechanism models of PCPI and PCBI directly interact with Hg2+.Hg2+ shows excellent quenching effects on the fluorescence of poly(3-aminocarbazole) derivatives (PCPI and PCBI) captaining N -type acceptor moieties imidazole. This graph vividly describes the process of fluorescence changing after adding Hg2+ according to the binding ratio calculated by the Job's plot curves. The adsorption process of Hg2+ by PCBI is also described. [Display omitted] • Two new types of Poly(3-aminocarbazole) derivatives containing N -type acceptor moieties were synthesized. • PCPI has excellent fluorescence performance with a large stokes shift of 153 nm. • PCPI and PCBI both show specific fluorescence quenching response to Hg2+. • PCBI also exhibits excellent adsorption ability of Hg2+ in water. [ABSTRACT FROM AUTHOR]

A method for the preparation of di- and trifluoromethyl derivatives of pyridines containing a tricyanobutadiene fragment has been suggested. Di- and trifluoromethyl-substituted [3-cyanopyridin-2(1H)-ylidene]malononitriles have been synthesized via reaction of malononitrile dimer with fluorinated acetylacetone derivatives. Optical properties of the obtained compounds in solution and in the solid state have been studied. [ABSTRACT FROM AUTHOR]

Boron-based blue light-emitting materials, 3,11-bis(10-phenylanthracen-9-yl)-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene [PA-DOBNA] was prepared with the composition of DOBNA core moiety and 9-phenylanthracene (PA) moiety as side group. The synthesized material showed excellent thermal stability with a high Td of > 400 °C. The doped device using dopant exhibited current efficiency (CE) of 2.90 cd/A and EQE of 4.40% at a current density of 10 mA/cm2. Commission Internationale de L'Eclairage (CIE) coordinates for non-doped and doped devices are (0.16, 0.18) and (0.15, 0.06) corresponding to the EL peaks at 457 and 446 nm, respectively. In addition, the doped device data showed a deep-blue emission of CIE (x = 1.15, y = 0.06) suitable for UHD-TV. [ABSTRACT FROM AUTHOR]

The development of stimuli‐responsive fluorescent materials in water based on organic molecule has drawn significant interest. Herein, we designed and synthesized an amphiphilic molecule M containing a fixed tetraphenylethylene moiety (FTPE) as hydrophobic part and tri(ethylene glycol) (TEG) chains as hydrophilic part. Notably, the FTPE moiety is aggregation‐induced emission (AIE) active, while the TEG chains are thermo‐responsive. M can self‐assemble into fluorescent nanoparticles (NPs) in water, which showed lower critical solution temperature (LCST) behavior. Moreover, its clouding point can be reversibly tuned upon the concentration variation. Interestingly, the NPs can be acted as a fluorescence thermometer in aqueous media owing to their unique AIE and LCST behaviors. Our work herein not only provides an integration strategy to construct stimuli‐responsive fluorescent materials but also shows great potential in biological applications including bioimaging and biosensors. [ABSTRACT FROM AUTHOR]

Two kinds of planarized phenyldithienylboranes, which contain (CH3)2C‐ or CH2‐bridging moieties, were synthesized. The difference of the bridging moieties affects their packing structures and photophysical properties. In particular, the (CH3)2C‐bridged derivative exhibits a large Stokes shift, unusual for such planarized compounds, that results from a large structural relaxation in the excited state. A series of π‐extended derivatives was synthesized, among which a p‐(diphenylamino)phenyl‐substituted derivative shows large solvatochromism in the fluorescence spectra, while maintaining high quantum yields even in polar solvents. The Lewis acidity of the phenyldithienylborane derivatives was also assessed by titration with pyridine. The Lewis acidity of the boron center is affected not only by the difference in the steric bulk of the bridging moieties, but also by the electronic effect of the substituents introduced at remote positions relative to the boron atom. These results demonstrate the characteristic features of planarized phenyldithienylboranes as building blocks for boron‐based π‐electron materials. [ABSTRACT FROM AUTHOR]

Featured Application: Birefringent film, photoalignment layer, polarized light-emitting film. Thermally stimulated photoinduced reorientation of liquid crystalline (LC) polymethacrylate composed of a phenyl benzoate mesogen connected with N-benzylideneaniline (NBA2) end moiety exhibits a significant molecular reorientation (D > 0.7) when the film is exposed to linearly polarized 313 nm light and subsequently annealed in the LC temperature range of the material. Hydrolysis of the NBA2 end moieties yields an oriented mesogen with phenylamine moieties without distorting the oriented structure. In situ condensation of 2-hydroxybenzaldehyde derivatives and phenylamine moieties yields oriented N-salicylideneaniline side groups. The resultant film displays a polarized fluorescence with a polarization ratio up to 3.4. [ABSTRACT FROM AUTHOR]

A fluorescence 'turn-on' probe for the detection of thiols was prepared in three steps. A diaminoterephthalate chromophore (λabs = 472 nm) was equipped with a maleimide moiety as reactive group. Upon conjugate addition of the thiol, the fluorescence intensity is increased by a factor of about twenty (λem = 567 nm, quantum yield Φ = 1% → 14%). The probe is used to establish a quantitative assay for glutathione. [ABSTRACT FROM AUTHOR]

Herein, an aggregation-induced emission (AIE)-based sensor, 4-(1,2,2-triphenylvinyl)benzoxime (TPE-phos), has been rationally designed for phosgene detection. The sensor has a tetraphenylethylene unit combined with an oxime moiety. TPE-phos undergoes nitrile formation after the oxime group reacts with phosgene, which will give a significant "light-up" fluorescence due to the AIE effect within seconds. [ABSTRACT FROM AUTHOR]

Most biological molecular complexes consist of multiple functional domains, yet rationally constructing such multifunctional complexes is challenging. Aptamers, the nucleic acid-based functional molecules, can perform multiple tasks including target recognition, conformational changes, and enzymatic activities, while being chemically synthesizable and tunable, and thus provide a basis for engineering enhanced functionalities through combination of multiple units. However, the conventional approach of simply combining aptamer units in a serial manner is susceptible to undesired crosstalk or interference between the aptamer units and to false interactions with non-target molecules; besides, the approach would require additional mechanisms to separate the units if they are desired to function independently. It is clearly a challenge to develop multi-aptamer complexes that preserve independent functions of each unit while avoiding undesired interference and non-specific interactions. By directly in vitro selecting a 'trans' aptamer complex, we demonstrate that one aptamer unit ('utility module') can remain hidden or 'inactive' until a target analyte triggers the other unit ('sensing module') and separates the two aptamers. Since the operation of the utility module occurs free from the sensing module, unnecessary crosstalk between the two units can be avoided. Because the utility module is kept inactive until separated from the complex, non-specific interactions of the hidden module with noncognate targets can be naturally prevented. In our demonstration, the sensing module was selected to detect serotonin, a clinically important neurotransmitter, and the target-binding-induced structure-switching of the sensing module reveals and activates the utility module that turns on a fluorescence signal. The aptamer complex exhibited a moderately high affinity and an excellent specificity for serotonin with ∼16-fold discrimination against common neurotransmitter molecules, and displayed strong robustness to perturbations in the design, disallowing nonspecific reactions against various challenges. This work represents the first example of a trans aptamer complex that was in vitro selected de novo. The trans aptamer complex selected by our strategy does not require chemical modifications or immediate optimization processes to function, because the complex is directly selected to perform desired functions. This strategy should be applicable to a wide range of functional nucleic acid moieties, which will open up diverse applications in biosensing and molecular therapeutics. [Display omitted] • In vitro selection strategy for trans aptamer complex is reported. • Utility module can remain inactive until target triggers the sensing module. • Structure-switching causes the complex to separate and activate fluorescence signal. • Undesired crosstalk, interference and non-specific binding can be avoided. • Complex shows strong target specificity with 16x higher signal than from non-target. [ABSTRACT FROM AUTHOR]

A series of D‐A‐D and D‐A‐A conjugated compounds composed of a benzoxadiazole core and corresponding amino moiety were synthesized. Their photoluminescent properties in different states were investigated as well. In the solution state, some compounds were observed to possess the usual anti‐Kasha's emission in toluene and the solvatofluorochromic phenomenon. Meanwhile, compound 1 a could be utilized as fluorescent chemosensor for the environmental acidity, and 2 c could be developed for detecting fluoride anion. Moreover, they were emissive in powders and films, and 2 d could be applied to the emissive layer in red OLEDs. [ABSTRACT FROM AUTHOR]

Sugar chain immobilized polymer particles having both magnetic and fluorescent properties can be expected to be useful in a wide variety of biomedical applications such as the detection, separation, and purification of proteins, viruses, or bacteria, because sugar chains specifically adsorb them. Since high magnetic responsiveness is required for such applications, we attempted to fabricate core-shell particles consisting of a submicron-sized magnetic core and a thin polymer shell (nano- to dozens of nanometers thick) that incorporates a fluorescent dye, with sugar molecules immobilized on the surface. Soap-free emulsion polymerization using methyl methacrylate (MMA) monomer and potassium persulfate (KPS) initiator in the presence of aminopropyltrimethoxysilane-treated Ni particles, octyl-β-D-glucopyranoside (octyl-glc), and rhodamine B (RhB) produced a glucose-immobilized fluorescent PMMA thin shell on a Ni particle (Ni/PMMA/RhB/octyl-glc). Electrostatic interaction was used both to incorporate RhB into the PMMA shell and to coat the Ni core with the PMMA-RhB shell. Glucose was immobilized on the PMMA shell by embedding a hydrophobic octyl group derived from octyl-glc in the PMMA matrix, and the resulting sugar-immobilized PMMA shell was able to adsorb protein (concanavalin A; a protein that specifically adsorbs glucose). The resulting Ni/PMMA/RhB/octyl-glc particles were well-dispersed in water, detected by highly sensitive fluorescence techniques, and could be collected by a magnet within 10 sec. They are expected to be applied to detect biological substances such as various proteins and viruses by changing the glucose moiety of the particle surface to other functional glycans. [ABSTRACT FROM AUTHOR]

A novel pyrene-pyridyl conjugated oligomer (OPP-OMe) was conveniently prepared by one-pot Sonogashira coupling. Intriguingly, it was found that introducing only one methoxy moiety at the 4-pyridyl position can be sufficient for creating an oligomer-based ultrafine reactive fluorescent nanoprobe, i.e., OPP-OMe NPs (ca. 2.5 nm in diameter). Spectral analyses and elucidation of the intermediate structure revealed that the methoxy triggered-oxidation, together with nanoaggregation of OPP-OMe NPs, results in rapid, specific and supersensitive sensing of hypochlorite (LOD, 0.3 nM, S/N = 3). [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Smart fluorescent patterns enable dynamic color variation under external stimuli, showing a much higher security level in the field of anti‐counterfeiting. However, there is still lacking of a simple and convenient way to achieve dynamic fluorescence changes. Herein, a fluorescent organohydrogel made up of a poly(N,N‐dimethylacrylamide‐co‐isopropylacrylamide) (p(DMA‐NIPAM)) hydrogel network and a poly(lauryl methacrylate) (PLMA) organogel network was fabricated via a two‐step interpenetrating technique. The former network bears naphthalimide moieties (DEAN, green fluorescent monomer) and the later contains 6‐acrylamidopicolinic acid (6APA, fluorescent ligand), leading to emitting green fluorescence. When Eu3+ was introduced and coordinated with 6APA, the organohydrogel displays red fluorescence, which can further emit yellow after applying thermal stimulus. Furthermore, by adjusting the proportion of comonomers, various organohydrogels can be obtained, which can be programmed and act as an effective platform for the encryption and decryption of secret information. [ABSTRACT FROM AUTHOR]

New D-π-A-type chromophores that simultaneously incorporate N,N-dimethylaminophenyl moiety as the terminal electron-donating group and either (5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile (DCM-1) or (6-methyl-4H-pyran-4-ylidene)malononitrile (DCM-2) unit as the terminal electron-withdrawing group were synthesized. Vinylene moiety and azo group served as the π-spacer. A comparative analysis of optical and electrochemical properties of the synthesized chromophores revealed that the replacement of the DCM-1 unit with the DCM-2 moiety led to chromophore band gap broadening and a decrease in the molar extinction coefficient value; while the replacement of the DCM-1 unit with the DCM-2 one in the chromophores bearing the vinylene π-spacers led to a sharp increase in the fluorescence quantum yield. [ABSTRACT FROM AUTHOR]

A fluorogenic probe for the specific detection of IMP-1 β-lactamase activity has been developed. This imaging reagent features a unique trans-acetylamino cephalosporin as an enzymatic recognition moiety, exhibiting excellent selectivity to IMP-1 β-lactamase over other β-lactamases, including serine- and metallo-β-lactamases. The selective activation of the probe by IMP-1 β-lactamase leads to over 30-fold enhancement in the fluorescence intensity, which allows enzyme activity to be reported with high sensitivity. [ABSTRACT FROM AUTHOR]

Herein, we show the synergistic combination of aggregation-caused quenching (ACQ) and aggregation-induced emission (AIE) units into two hexagonal metallacycles. The resultant metallacycles displayed emergent photophysical properties including tunable fluorescence using the polarity and solubility of the solvents as well as enhanced emissive efficacy. Our work demonstrates the synergistic enhancement of these two orthogonal effects via coordination-driven self-assembly. [ABSTRACT FROM AUTHOR]

Background: New amino derivatives of NBD type are of high interest due to their strong fluorescence, while compounds containing a disulphide moiety are of high interest in nano-chemistry due to their easiness of attaching to noble nanoparticles. Therefore, in this work a new fluorescent derivative of NBD and cystamine was obtained. Methods: The reaction between cystamine and NBD-chloride occurs straightforwardly, and the isolated new compound was characterized by IR, UV-Vis, fluorescence, 1H- and 13C-NMR, MS, etc. Results: Structural analysis confirmed the proposed structure and highlighted the fluorescence behavior. Conclusions: A new fluorescent derivative of cystamine was obtained and characterized by different means. [ABSTRACT FROM AUTHOR]

Electron‐deficient heteroacenes that contain two tricoordinate boron atoms in their acene skeletons and planarized phenyl ether moieties at their periphery were synthesized via the borylation of silicon‐bridged precursors. X‐ray crystallographic analysis revealed quinoidal structures, which give rise to two‐step reversible redox processes for both the reduction and oxidation. These compounds exhibit intense absorption and sharp fluorescence bands with vibronic structures in the near‐infrared (NIR) region. These properties originate from the push–pull effect along the long axis of the molecule derived from the electron‐donating ether moieties and the electron‐accepting boron moieties. Of particular note is the NIR emission of the thienothiophene‐centered heteroacene, which has a maximum at 952 nm with a narrow band width of 309 cm−1 in cyclohexane. A Franck–Condon analysis revealed the crucial role of the sterically less‐hindered thienothiophene spacer in achieving this sharp emission band. [ABSTRACT FROM AUTHOR]

Biodegradable nanostructures displaying aggregation‐induced emission (AIE) are desirable from a biomedical point of view, due to the advantageous features of loading capacity, emission brightness, and fluorescence stability. Herein, biodegradable polymers comprising poly (ethylene glycol)‐block‐poly(caprolactone‐gradient‐trimethylene carbonate) (PEG‐P(CLgTMC)), with tetraphenylethylene pyridinium‐TMC (PAIE) side chains have been developed, which self‐assembled into well‐defined polymersomes. The resultant AIEgenic polymersomes are intrinsically fluorescent delivery vehicles. The presence of the pyridinium moiety endows the polymersomes with mitochondrial targeting ability, which improves the efficiency of co‐encapsulated photosensitizers and improves therapeutic index against cancer cells both in vitro and in vivo. This contribution showcases the ability to engineer AIEgenic polymersomes with structure inherent fluorescence and targeting capacity for enhanced photodynamic therapy. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: It is of great significance to develop rapid crosslinking strategies to enrich the functions of hydrogels and simplify the preparation process of hydrogels. Herein, we applied the ternary condensation reaction of o‐phthalaldehyde (OPA) with thiol and amino moieties to construct hydrogel networks with fast gelation rate, excellent mechanical strength, and favorable stability. The obtained hydrogels exhibited rapid gelation transition even at a low solid content. The ternary condensation was traced in the gelation process and demonstrated as a pseudo‐first‐order reaction irrespective of the gelation threshold. Interestingly, the crosslinking sites of these hydrogels were constructed with isoindole rings, endowing the materials with fluorescent functions without an extra chemical grafting process. The OPA ternary condensation reaction was a simple and universal strategy towards fabrication of natural or synthetic polymer gels from polysaccharides, proteins, and synthetic polymers, which is expected to have potential biomedical applications. [ABSTRACT FROM AUTHOR]

Unlike amyloid aggregates, amorphous protein aggregates with no defined structures have been challenging to target and detect in a complex cellular milieu. In this study, we rationally designed sensors of amorphous protein aggregation from aggregation‐induced‐emission probes (AIEgens). Utilizing dicyanoisophorone as a model AIEgen scaffold, we first sensitized the fluorescence of AIEgens to a nonpolar and viscous environment mimicking the interior of amorphous aggregated proteins. We identified a generally applicable moiety (dimethylaminophenylene) for selective binding and fluorescence enhancement. Regulation of the electron‐withdrawing groups tuned the emission wavelength while retaining selective detection. Finally, we utilized the optimized probe to systematically image aggregated proteome upon proteostasis network regulation. Overall, we present a rational approach to develop amorphous protein aggregation sensors from AIEgens with controllable sensitivity, spectral coverage, and cellular performance. [ABSTRACT FROM AUTHOR]

We have developed an unprecedented transition metal–free approach for the direct fluorescence turn-on labeling of natural oligonucleotides through selective N6-arylation of adenosine moieties. This method allows the simple and direct fluorescence labeling of natural unmodified DNA and RNA, but is dependent on the secondary structure, favoring single-stranded structures. [ABSTRACT FROM AUTHOR]

A novel two-dimensional Zn(II) coordination polymer [Zn(II) CP], [{Zn(L)Zn(OAc–)(µ-OAc–)}4]n· 2nCH3CH2OH has been self-assembled from Zn(OAc)2·2H2O. It contains pyridine-terminal salamo-type ligand H2L. Structure of the product has been determined. The Zn(II)CP contains two kinds of Zn(II) ions of different coordination modes. The Zn1 center is characterized by five-coordinated triangular biconical geometry. The Zn2 center is a six-coordinated octahedral center. Using these as junction points and the fully deprotonated ligand (L)2– moieties containing pyridine-terminal as a linker, the 2-D coordination polymer with two kinds of different pores [27.47 × 11.77(23) Å2; 11.97 × 4.51(17) Å2] has been obtained. The Zn(II) CP can fluoresce green and be used in fluorescent materials. Short-range interactions on Zn(II) CP surface have been studied by Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

A gold‐catalyzed tandem cycloisomerization/ring expansion of alkynyl spiro‐epoxyoxindoles was developed, affording furo[2,3‐c]quinolinones in good to excellent yields with broad substrates scope. This methodology provides an efficient approach to construct furo[2,3‐c]quinolinone moieties. Moreover, the fluorescence properties of furo[2,3‐c]quinolinones are also investigated. [ABSTRACT FROM AUTHOR]

There is increasing interest in the development and applications of synthetic receptors that recognize target biomolecules in aqueous media. We have developed a new tweezer‐type synthetic receptor that gives a significant fluorescence response upon complexation with heme in aqueous solution at pH 7.4. The synthetic receptor consists of a tweezer‐type heme recognition site and sulfo‐Cy5 as a hydrophilic fluorophore. The receptor–heme complex exhibits a supramolecular amphiphilic character that facilitates the formation of self‐assembled aggregates, and both the tweezer moiety and the sulfo‐Cy5 moiety are important for this property. The synthetic receptor also exhibits significant fluorescence responses to biliverdin and bilirubin, but shows very weak fluorescence responses to flavin mononucleotide, folic acid, and nicotinamide adenine dinucleotide, which contain smaller π‐scaffolds. [ABSTRACT FROM AUTHOR]

[Display omitted] The "clip-cycle" synthesis of 2-pyridazinones containing enaminonitriles from thioesters with dicyanohydrazones is achieved through a AgOAc-promoted acylation-cyclization-tautomerization cascade reaction. Moreover, the obtained 2-pyridazinones are further transformed into biologically significant bicyclic-fused pyridazinones exhibiting intriguing fluorescence emission properties. Additionally, quantum chemical calculations were performed to provide a rational explanation for the observed photophysical characteristics. [ABSTRACT FROM AUTHOR]

A series of novel fluorescence carbazole-functionalized building blocks with increased π-conjugated systems have been synthesized and investigated as potential candidates for carrying out complex formation reactions with metal salts. The combination of data obtained from elemental analysis, IR and NMR spectroscopy, mass-spectrometry and GPC allows us to confirm the suggested linear and bulky dendron's structures. The chemical modification of dendrons with functional groups affects the thermal stability phase behavior and fluorescent properties. Dendrons showed the positive solvatochromism effect, which was confirmed by the red shift when the polarity of the solvents was increased. The fluorescence lifetime for dendrons of the first and second generation decreases with decreasing solvent polarity. The study of the spectral properties of compounds in the solid state showed that the synthesized molecules exhibit bluish-white fluorescence. [Display omitted] • A series of novel fluorescence carbazole-functionalized building blocks with increased π-conjugated systems. • The chemical modification of dendrons with functional groups affects the thermal stability and phase behavior. • The lifetime of fluorescence at long wavelength emission is on the nanosecond scale. [ABSTRACT FROM AUTHOR]

Heterometallic binuclear Ru–Pt and trinuclear Zn–Pt complexes were prepared via self-assembly by attaching PtII-tpy (tpy = 2,2′:6′,2′′-terpyridine) onto the RuII-tpy and ZnII-bis(tpy) moiety. The visible absorption bands for Ru–Pt complexes are primarily due to RuII → tpy MLCT transitions with some overlap from PtII → tpy MLCT, while no MLCT transition is observed for the Zn–Pt complex. The emission intensity of the Ru–Pt complexes was improved relative to the mononuclear RuII precursor; however, the emission of Zn–Pt was decreased when compared with strongly emissive ZnII-bis(tpy). Z-scan results revealed relatively high two-photon absorption (TPA) cross sections σ2, with maximal values of 962 GM for Ru–Pt and 200 GM for Zn–Pt. All the heterometallic complexes were proved to localize preferably into lysosomes by confocal fluorescence imaging results, which also showed improved cell-free 1O2 quantum yield compared to their mononuclear precursor. [ABSTRACT FROM AUTHOR]

Spectral, luminescent, and photochemical properties of 3-styrylbenzo[f]quinoline derivatives with a methoxy group in the 2-position (2MSBQ) and a methoxymethylene group in the 4-position (4MMSBQ) of the styryl moiety have been investigated. Both compounds luminesce in the range of 380–480 nm and undergo reversible photoisomerization with quantum yields of 0.2–0.5. The side reaction of photocyclization of the cis-isomer is observed for 2MSBQ in addition to photoisomerization. Upon protonation, photocyclization is blocked and both compounds undergo only photoisomerization, with the quantum yields of photoisomerization increasing and those of fluorescence decreasing. The absorption and fluorescence spectra shift bathochromically. Geometry and electronic structure of the compounds were calculated with the use of DFT by a B3LYP/6-31G* method. By calculation using the TD-B3LYP/6-31G* method and the analysis of the transitions between molecular orbitals, the observed differences in the absorption spectra of 2MSBQ and 4MMSBQ have been explained. The comparison of the obtained results with the SBQ derivatives studied earlier shows several interesting substituent effects, which are explained in terms of the diabatic mechanism of photoisomerization. [ABSTRACT FROM AUTHOR]

Rationally designed mutations on recombinant arginine deiminase (ADI) could act as a 'turn-off' L-arginine (L-Arg) fluorescent biosensor and provide an alternative method for rapid determination of L-Arg. Double mutations were introduced on the Cys251➔Ser251 and Thr265➔Cys265 of recombinant ADI, rendering a single cysteine present on the protein surface for the site-specific attachment of a fluorophore, fluorescein-5-maleimide. The double mutations on ADI (265C) and its fluorescein-labelled form (265Cf) conserved the catalytic efficiency of wild-type ADI. Upon binding to L-Arg, 265Cf induced structural conformational changes and rendered the fluorescein moiety to move closer to Trp264, resulting in fluorescence quenching. The duration of fluorescence quenching was dependant on the L-Arg concentration. A linear relationship between the time at the maximum rate of fluorescence change and L-Arg concentrations, which ranged from 2.5 to 100 μM, was found with R2 = 0.9988. The measurement time was within 0.15–4 min. Determination of L-Arg concentration in fetal bovine serum could be achieved by the standard addition method and without sample pre-treatment. The result showed a good agreement with the one determined by mass spectrometry, suggesting our biosensor as a promising tool for the detection of L-Arg in biological samples. • L-arginine was rapidly detected by fluorescent biosensor with one-enzyme system. • L-arginine level detected by the biosensor was comparable with mass spectrometry. • Determination of L-arginine level in complexed-matrix samples could be performed. [ABSTRACT FROM AUTHOR]