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PEGylated 2-(2-(6-(dimethylamino)benzooxazol-2-yl)vinyl)quinolin-8-ol (BQ-mPEG) was synthesized, which exhibited strong fluorescence at 610 nm (φf = 0.11) and a large Stoke's shift (Δλ = 202 nm) in the aqueous solution. The fluorophore displayed a two-photon absorption characteristic and a strong red emission (λem = 625 nm) was observed with NIR (950 nm) irradiation. The feasibility of using BQ-mPEG as a fluorescent imaging reagent suggested that the fluorophore targets mitochondria, and with 950 nm excitation, bright fluorescence images in HeLa live cells were observed. Furthermore, the fluorophore exhibited some advantages of high photostability and pH stability, as well as low cytotoxicity. [ABSTRACT FROM AUTHOR]

Push--pull organic molecules have aroused wide interest in photochemistry and photophysics research communities. In this report, we present the synthesis, characterisation, photophysical and nonlinear optical property studies of a new organic fluorophore (AA2) with a unique push--pull molecular configuration: acceptor--p-bridge--donor--p-bridge--acceptor (A--π--D--π--A) constituted with phenothiazine as the donor moiety. A thorough investigation to validate its structure was undertaken through ¹H, 13C NMR and MALDI-TOF mass spectrometry. A variety of studies were undertaken to unravel its optical properties both experimentally and theoretically. A systematic investigation probing its optical absorption and emission characteristics revealed its strong dependence on solvent polarity, which confirmed the crucial role played by the intra molecular charge transfer (ICT) process emerging from its unique molecular and electronic structure. Such a strong structure--property correlation could be exploited for various optoelectronic applications, which triggered us to explore AA2 for photonics applications driven by nonlinear optical responses. Our nonlinear optical investigations confirmed strong excited state absorption at 532 nm when excited in the nanosecond regime using the Z-scan technique. This opened up yet another avenue of exploring it for optical limiting applications. The estimated optical limiting threshold for an AA2 molecule is about 0.98 J cm-2, which proved its high suitability for such photonics applications while outperforming many other organic fluorophores and benchmarked nanostructures under similar experimental evaluation. This is one of the very first reports on phenothiazine with an A--π--D--π--A configuration accompanied by excellent nonlinear optical properties. [ABSTRACT FROM AUTHOR]

Six-membered-diaza ring of cinnoline has been fused on naphthalimide dye to give a donor-acceptor system called CinNapht. This red shifted fluorophore, that can be synthesised in gram scale, exhibits a large Stoke shift and a fluorescence quantum yield up to 0.33. It is also characterized by a strong solvatochromic effect from green to red emission as well and can be used for bio-imaging., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The hexaarylbenzene (HAB)-based push–pull fluorophore HAB-MeO-TPy with the 2,2′:6′,2″-terpyridine (TPy) unit as an acceptor and the methoxy (MeO) group as a donor was developed. It was observed that HAB-MeO-TPy exhibited an unusual uphill-type emission with increasing solvent polarity from cyclohexane to DMSO. By comparison with a previously reported fluorophore HPB-MeO-DCV, a structure–property relationship regarding this uncommon fluorescence behavior was disclosed. Furthermore, the sensing properties of HAB-MeO-TPy for metal ions were also investigated. In the presence of Fe2+, HAB-MeO-TPy displayed a visual color change from colorless to magenta, indicating that HAB-MeO-TPy can act as a "naked eye" sensor for Fe2+ detection. From absorption titration experiments, the detection limit was determined to be 1.50 × 10−7 M. In addition, HAB-MeO-TPy was successfully applied to detect Fe2+ in real water samples. [ABSTRACT FROM AUTHOR]

Three new fluorescent enantiopure pyridino-18-crown-6 ethers containing a benzothiazole unit were prepared, and the enantiomeric discrimination of these sensor molecules toward the hydrogen perchlorate salts of 1-phenylethylamine, 1-(1-naphthyl)ethylamine, phenylglycine methyl ester and phenylalanine methyl ester was studied in acetonitrile by fluorescence spectroscopy. The ligands revealed appreciable or moderate selectivity toward the enantiomers of hydrogen perchlorate salts of 1-phenylethylamine, 1-(1-naphthyl)ethylamine and phenylglycine methyl ester. Image 1 [ABSTRACT FROM AUTHOR]

Abstract The deep blue organic light emitting diodes (OLEDs) are necessary for solid-state lighting (SSL) and flat panel displays. In the practical application of OLEDs, high efficiencies and luminance with simple device structure, are highly desirable. Hence, we have designed and synthesized three blue (Donor-Acceptor) fluorophores with linear, bent and star-shaped molecular geometry by incorporating triphenylamine (TPA) as a hole transporting unit and imidazole as an electron transporting unite with electron withdrawing Ph-CF 3 moiety at the N1 position of imidazole unit. The synthesized fluorophores were structurally characterized by Nuclear Magnetic Resonance Spectroscopy (NMR) and Mass spectroscopy. The linear-shaped fluorophore structurally characterized by single crystal X-ray diffraction. Photophysical, electrochemical and electronic (theoretical) properties of the synthesized fluorophores were systematically investigated. All the fluorophores are showing deep blue emission in DCM solution. The synthesized fluorophores are shown good quantum yield (Φ) in solution and solid phase. The structurally simple OLEDs devices were fabricated by using these fluorophores as emitters. All the fluorophores showed deep blue electroluminescence (EL) emission with good device efficiency. Among all the devices, based on TBIMTPA with a 5 wt % dopant concentration exhibited better performance in the series with a maximum luminance of 994 cd/m2, a current efficiency of 2.6 cd/A, a power efficiency of 1.0 lm/W and an EQE of 3.2% at brightness of 100 cd/m2. These results indicate that the introduction of imidazole-based accepter on the TPA core is a favorable design strategy towards deep blue emitters. Graphical abstract Image 1 Highlights • Donor-Acceptor blue fluorophores were designed and synthesized. • Fluorophores shown good quantum yield (Φ) in solution and solid phase. • HOMO and LUMO separation endows them with good carrier transporting property. • TBIMTPA based OLED showed deep-blue emission with CIE of (0.16, 0.08). • TBIMTPA (5 wt %) based device exhibited good device performance with EQE of 3.2%. [ABSTRACT FROM AUTHOR]

Abstract Among the wide-range of chemical reactions that can be performed on BODIPYs, attack on the boron atom opens the door to the synthesis of numerous more or less complex fluorophores. Moreover, the modifications that occur preserve the unique photo-physical properties of while improving their quantum yield, stability and solubility either in water or in organic solvents. This field has been far less investigated to date than dipyrrin core derivatization has. The aim of this work is to provide a comprehensive review of the different synthetic methodologies reported for the introduction of alkyl or alcohol substituents on the boron of BODIPYs. Highlights • Description of B-O and B-C functionalization strategies for BODIPYs and aza-BODIPYs. • Substitution strategies description of fluorine atoms on BODIPY dyes. • Description of the synthetic methodologies for the introduction of alkyl or alcohol substituents on the boron of BODIPYs. [ABSTRACT FROM AUTHOR]

Three dimesitylborane-containing fluorophores with various π-conjugated systems attached at the 9th position of carbazole, namely, 9-(4′-bromobiphenyl-4-yl)-9 H -carbazole (Cz 9 Ph 2 B), 9-(4-(5-(dimesitylboryl)thiophen-2-yl)phenyl)-9 H -carbazole (Cz 9 ThPhB), and 9-(4-(4-(dimesitylboryl)styryl)phenyl)-9 H -carbazole (Cz 9 SB) were synthesized and their photophysical and electroluminescent properties were investigated for application in nondoped blue OLEDs as well as red phosphorescent OLEDs (PhOLEDs). The electron-accepting dimesitylboryl group and various π-conjugated segments appended to the electron-donating carbazole moiety impart the three fluorophores with bipolar transporting ability, and their energy levels are matched with those of the adjacent carrier-transporting layers. These bulky fluorophores are thermally stable with glass transition temperatures and degradation temperatures reaching up to 105 and 383 °C, respectively. In addition, efficient nondoped Cz 9 PhThB- and Cz 9 SB-based blue OLEDs with maximum currents of 1.51 and 4.03 cd A −1 and external quantum efficiencies (EQE) of 2.30 and 4.72% were achieved, respectively. Notably, the Cz 9 Ph 2 B-based red PhOLEDs exhibits a relatively low turn-on voltage (3.3 V) and high electroluminescence efficiencies (maximum current = 23.12 cd A −1 and EQE = 14.10%). Their performance is superior to that of the corresponding device using conventional 4,4′- N , N ′-dicarbazolbiphenyl as the host material. Moreover, a maximum brightness of 39700 cd m −2 was also achieved. [ABSTRACT FROM AUTHOR]

A novel fluorescence probe PISOH comprising phenanthroimidazole as a fluorophore and thioacetal as recognition unit is designed and synthesized. PISOH displays high selective turn-on fluorescence response toward Hg 2+ with no interference from other metal cations, such as Cu 2+ , Ag + , Fe 3+ , Pb 2+ , etc. PISOH can be converted to the corresponding aldehyde PICHO in the presence of Hg 2+ , based on the Hg 2+ promoted deprotection of thioacetal. Moreover, the fluorescence emission and sensing properties of PISOH can be modulated by surfactants in aqueous solution. PISOH exhibits a detection limit (LOD) of 1.16 nM for Hg 2+ in aqueous Triton X-100 solution, much lower than that in DMF (LOD = 6.83 nM). The response time of PISOH for Hg 2+ is around 1 min, suitable for rapid detection of Hg 2+ . Furthermore, the probe can be used to monitor Hg 2+ effectively in living cells by fluorescence imaging. This work represents a novel and simple strategy for sensing of Hg 2+ in pure water by using commercially available surfactants to solubilize fluorescent probe. [ABSTRACT FROM AUTHOR]

The cascade reaction of ethyl pyrazole-5-carboxylate with α, β-unsaturated ester leading to 4-hydroxy pyrazolo[1,5-a]pyridine derivatives has been developed. A possible mechanism is proposed. The resulting pyrazolo[1,5-a]pyridines present strong fluorescence in solutions. [ABSTRACT FROM AUTHOR]

Annularly fused azaBODIPY-based organic fluorophores (HBPs 2) containing up to 13 aromatic ring fusions were synthesized by a Suzuki coupling reaction with bromoazadipyrromethenes and a subsequent regioselective oxidative ring-fusion reaction. X-ray analysis indicates almost planar dipyrrin cores for all crystals but overall curved or "wave" conformations for those HBP dyes. These molecules exhibit unique structural and physical properties including excellent spectral selectivity (negligible absorption between 300 and 700 nm), sharp near-infrared (NIR) absorption (up to 878 nm) and emission (up to 907 nm), large extinction coefficient (up to 4.5 × 105 M-1 cm-1), and excellent photostabilities. [ABSTRACT FROM AUTHOR]

The successful design and pre-clicked synthesis of a non-toxic and cytosol trackable carboplatin-like near infrared fluorophore conjugate via strain-promoted azide alkyne cycloaddition (SPAAC) is reported. Reaction of cis -[Pt(2-azidopropane-1,3-diamine)(cbdca)] (cbdca = cyclobutane-1,1-dicarboxylato) and a bicyclo[6.1.0]non-4-yne near-infrared (NIR) azadipyrromethene fluorophore gave the corresponding clicked Pt-Fluorophore conjugate. The X-ray crystal structure of cis -[Pt(2-azidopropane-1,3-diamine)(cbdca)] was determined featuring the azide on the bidentate 1,3-diaminopropane ligand. The Pt-fluorophore conjugate is the first example of a Pt conjugate clicked via strain-promoted azide alkyne cycloaddition (SPAAC) where the reactive azide handle is on the amine carrier ligand. The in vitro cytotoxicity and widefield fluorescence imaging of the Pt-Fluorophore conjugate in A2780P and A2780cisR cells are described. [ABSTRACT FROM AUTHOR]

Abstract: 2‐(1,3‐Benzothiazol‐2‐yl)‐4‐methoxy‐6‐(1,4,5‐triphenyl‐1H‐imidazol‐2‐yl)phenol (BTImP) is an excited‐state intramolecular proton transfer (ESIPT) fluorophore, containing an acid‐stimuli‐responsive intramolecular hydrogen bond (H‐bond) that can switch from the central phenolic proton to the imidazole (Im) or benzothiazole (BT) nitrogen atoms. Here, we demonstrate that BTImP shows full‐color (red, green, blue, and white) emission upon the addition of different concentrations of HClO4 or, with time, after the addition of HBF4. It also shows thermally dependent color changes from pink through white to blue in a narrow temperature range of 25–60 °C. 1H and 15N NMR measurements suggest that, after the green fluorescent BTImP is protonated at its Im nitrogen atom, a conjugate base anion coordinates to the imidazolium (HIm+) proton, forming two types of complexes with different coordination states. One state shows a significantly Stokes‐shifted red emission resulting from ESIPT at the BT side, whereas the other shows a typical Stokes‐shifted blue emission, probably caused by interaction of the anion with the phenolic proton, which breaks the H‐bond on the BT side. BF4− and ClO4− are effective in forming such a blue emitter, whereas Cl− and PF6− are not; this behavior depends on whether the anion can fit into the bidentate binding site consisting of HIm+ and the phenolic hydroxy group. [ABSTRACT FROM AUTHOR]

The Environment-related parameters, including pH, oxygen level and viscosity play pivotal functions in controlling the physical, chemical and biological performance of local molecules. Irregular modification in these features would cause cellular malfunction can indicate the onset of severe diseases or become a hallmark of the incidence of severe diseases. Recently, luminescent molecules have drawn research interest from the field of fluorescent chemosensors, which have been designed to respond to such parameters and to map their variations in vitro/in vivo. In this review, we have screened a numerous literature of various responsive chemosensors related to fluorescent recognition of pH, oxygen level, and viscosity. The fluorescence-based bio-imaging (FBI) techniques play an important role in advancing the knowledge of cellular processes at the molecular level, both in vitro / in vivo and support medical biology and modern medicine. The mono-, dual and multi-stimuli responsive luminescent materials have the ability to detect changes in several clinically important factors like pH, oxygen level, and viscosity. In contrast, we have surveyed and summarized the literature regarding the use of fluorescence-based materials to detect changes in pH, oxygen level and highlight the low-cost green synthetic method of organometallic complexes, properties, and applications of the main group luminescence-based materials in order to get high yield. [ABSTRACT FROM AUTHOR]

Pyoverdines are important siderophores that guarantee iron supply to important pathogenic and non-pathogenic pseudomonads in host habitats. A key characteristic of all pyoverdines is the fluorescent dihydroxyquinoline group that contributes two ligands to the iron complexes. Pyoverdines are derived from the non-ribosomally synthesized peptide ferribactin, and their fluorophore is generated by periplasmic oxidation and cyclization reactions of D-tyrosine and L-diaminobutyric acid. The formation of the fluorophore is known to be driven by the periplasmic tyrosinase PvdP. Here we report that the putative periplasmic oxidoreductase PvdO of Pseudomonas fluorescens A506 is required for the final oxidation of dihydropyoverdine to pyoverdine, which completes the fluorophore. The pvdO deletion mutant accumulates dihydropyoverdine, and this phenotype is fully complemented by recombinant PvdO. The autoxidation of dihydropyoverdine at alkaline pH and the presence of high copper concentrations can mask this phenotype. Mutagenesis of conserved residues with potential catalytic function identified Glu-260 as an essential residue whose mutation abolished function without affecting stability or transport. Glu-260 of PvdO is at the exact position of the active-site cysteine in the structurally related formylglycine-generating enzyme. Evolution thus used the same protein fold for two distinct functionalities. As purified PvdO was inactive, additional factors are required for catalysis. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a series of variously substituted 2,3‐dihydroquinolin‐4‐imines (DQIs) were synthesized from N‐substituted propargylanilines by copper(I)‐catalyzed annulation. The approach adopted in this study under mild, effective conditions exhibited broad substrate tolerance, particularly for functional groups substituted on anilines. Most of the DQI derivatives synthesized under optimal conditions were obtained in good isolated yields of 63–88 %. 2,3‐Dihydroquinolinimine thus obtained was easily converted to important structures like 2,3‐dihydroquinolone and tetrahydrobenzodiazepin‐5‐one, confirming the importance of this strategy in constructing various heterocycles. Surprisingly, 2,3‐dihydroquinolinimines thus obtained exhibited bright fluorescence with quantum yields up to 66 %. The density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations were performed for understanding the excited‐state nature of DQI system. Accordingly, a tailored DQI derivative bearing methoxy group at C‐6 position and acetoxy group at C‐7 position was designed and synthesized to give emission at 559 nm with redshift compared to the 7‐methoxy substituted DQI. A detailed study of DQI structures with their photophysical properties was performed with five control molecules and consequently demonstrated the uniqueness of the chemical structures of DQIs. [ABSTRACT FROM AUTHOR]

Understanding the structural properties of random packings of jammed colloids requires an unprecedented high-resolution determination of the contact network providing mechanical stability to the packing. Here, we address the determination of the contact network by a novel strategy based on fluorophore signal exclusion of quantum dot nanoparticles from the contact points. We use fluorescence labeling schemes on particles inspired by biology and biointerface science in conjunction with fluorophore exclusion at the contact region. The method provides high-resolution contact network data that allows us to measure structural properties of the colloidal packing near marginal stability. We determine scaling laws of force distributions, soft modes, correlation functions, coordination number and free volume that define the universality class of jammed colloidal packings and can be compared with theoretical predictions. The contact detection method opens up further experimental testing at the interface of jamming and glass physics. [ABSTRACT FROM AUTHOR]

DNA aptamers are a powerful class of molecules for sensing targets, but have been limited when applied to imaging in living animals because most aptamer probes are fluorescence-based, which limits imaging penetration depth. Photoacoustic (PA) imaging emerged as an alternative to MRI and X-ray tomography in biomedical imaging, due to its ability to afford highresolution images at depths in the cm range. Despite its promise, PA imaging is limited by a lack of strategies to design selective and activatable probes for targets. To overcome this limitation, we report design and demonstration of PA probes based on DNA aptamers that can hybridize to DNA strands conjugated to a near-infrared fluorophore/quencher pair (IRDye 800CW/IRDye QC-1) with efficient contact quenching. Binding of the target triggered a release of the DNA strand with the quencher and thus relief of the contact quenching, resulting in a change of the PA signal ratio at 780/725 nm. Using thrombin as a model, a relationship was established between the thrombin concentrations and the PA ratio, with a dynamic range of 0-1000 nM and a limit of detection of 112 nM. Finally, in vivo PA imaging studies showed that the PA ratio increased significantly 45 min after injection of thrombin but not with injection of PBS as a vehicle control, demonstrating the first aptamer-based activatable PA probe for advanced molecular imaging in living mice. Since in vitro selection can obtain aptamers selective for many targets, the design demonstrated can be applied for PA imaging of a number of targets. [ABSTRACT FROM AUTHOR]

A symmetrical linear D-π-A-π-D hexacatenar compound with 2,1,3-benzothiadiazole as the acceptor core connected at its 4,7 position with phenylthienylethynyl spacers has been designed and synthesized. This compound displays liquid crystalline property with oblique columnar mesophase and forms an organogel in dichloromethane. The investigation of photophysical and electrochemical properties reveals that this compound can exhibit broad and strong absorption band at the range of 300–700 nm with a low energy gap in solid state, meanwhile it exhibits highly red fluorescent emission and large Stokes shifts. [ABSTRACT FROM AUTHOR]

Two series of novel zwitterionic water-soluble pentamethine cyanine dyes with geometrically balanced structures were synthesized and characterized. One series of cyanine dyes is the «zwitterionic» fluorophores, which contain positively charged trimethylammonioalkyl and negatively charged sulfonate groups. The second series of cyanine dyes contains a sulfonate group on one indolenine nucleus and a carboxyl group linked through an N- acylsulfonamide bond on the other indolenine nucleus. Dye-modified deoxyuridine triphosphates were synthesized and evaluated as reagents for nucleic acid labeling using PCR with Taq DNA-polymerase. The efficiency of the incorporation of labeled nucleotides was investigated via real-time PCR and using a «KRAS-Biochip» commercial testing system. [ABSTRACT FROM AUTHOR]

A set of new oxazol-5-one fluorophores incorporating ethylene glycol chains terminated with an aldehyde unit has been synthesized and characterized structurally. Two pairs of compounds can be distinguished according to the substitution on the oxazol-5-one moiety: one pair bears a tolyl unit and the other a nitrophenyl unit. The difference within the pairs is the length of the ethylene glycol chain. The evaluation of absorption and emission properties of the new oxazol-5-one derivatives was carried out in seven different solvents of varying polarity, which showed intense absorption maxima at 384–418 nm and emission maxima at 430–607 nm, respectively. The solvatofluorism study of 3a and 3c revealed that their emission wavelengths are very sensitive to solvent polarity and are red shifted in polar solvents. 3a and 3c fluorophores exhibited high Stokes shift values between 4158 and 7921 cm − 1 . [ABSTRACT FROM AUTHOR]

Triazoliptycene fluorophores have been designed and synthesized, in which a three-dimensional propeller-like iptycene motif is employed to suppress intermolecular π-π stacking in the solid state. Key to the success of this modular synthesis is a stereoelectronic bias imposed by the iptycene scaffold, which assists the desired regioselectivity in the C-N cross-coupling step as the last-stage structure diversification from a common precursor. [ABSTRACT FROM AUTHOR]

A library of 20 styryl-based push–pull dyes derived from 6-amino substituted benzothiazoles were prepared by an efficient and practical synthetic route from low-cost starting materials. The dyes were firstly designed to present an effective anchoring site for subsequent conjugation. A series of aryl scaffolds, from substituted phenyl rings containing electron donating and withdrawing groups to polycyclic aromatic derivatives, were screened. The inductive effect of N-alkyl substituted benzothiazoles was also explored for three different arrangements. The investigation of the structure–photophysics relationship was performed by UV-vis absorption and steady-state fluorescence emission measurements in solution and by TD-DFT calculations. The dyes presented high brightness, absorption bands in the visible range (∼370–453 nm) and large solvatofluorochromism comprising all the visible spectrum, as a consequence of the strong intramolecular charge transfer (ICT) nature of their excited state. [ABSTRACT FROM AUTHOR]

Two novel organic fluorophores, containing bis-naphthylamide and quinoline motifs, have been designed and synthesized. One of the fluorophores contains an isobutylene unit and exhibits a significant aggregation-induced emission (AIE) and a remarkable highly selective ratiometric fluorescence response towards Zn2+ in solution as well as in human liver cancer cells. The AIE behavior of this fluorophore was fully verified by fluorescence and UV/Vis spectroscopy, quantum yield calculations, and single-crystal X-ray diffraction, which revealed an intricate crystal packing system. Conversely, a fluorophore that lacks the isobutylene moiety did not exhibit any significant fluorescent properties as a result of its more flexible molecular structure that presumably allows free intramolecular rotational processes to occur. [ABSTRACT FROM AUTHOR]

Among the various fascinating fluorescent compounds, excited-state intramolecular proton transfer (ESIPT) dyes have been drawing much attention due to their anomalously large Stokes shifts. Furthermore, ESIPT fluorophores are attractive as their fluorescence properties may be fine-tuned through facile chemical modifications of existing dyes. Varying the strength of the electron-donating and electron-withdrawing substituents anchored at different sites of the parent molecules, especially when incorporating these substituents at several different sites simultaneously, is an effective way to achieve targeted fluorescence properties. In the present study, a new family of 2-(2-hydroxyphenyl)benzothiazole (HBT)-based disubstituted derivatives, with substitutions at the 4′- and 5′-positions, were readily synthesized by the Suzuki coupling reaction. It was found that the electronic effects of the 5′-position substituents on the molecular orbital levels were opposite to that of the 4′-position substituents. Theoretical calculations demonstrate that the substituents at the 4′- and 5′-positions dramatically affect the HOMOs and the LUMOs, respectively, which is in conformity with experimental results and can be applied to predict shifts in fluorescence emission. Additionally, these derivatives show highly efficient keto-emission in the aggregated state. The X-ray crystallographic analysis shows that weak intramolecular interactions, which restrict intramolecular rotation, and strong intramolecular hydrogen bonding, which facilitates intramolecular proton transfer, are responsible for the intense keto-emission observed. Our study may provide experimentally and theoretically valuable instructions for designing other high-performance ESIPT fluorophores to meet the demands of specific applications. [ABSTRACT FROM AUTHOR]

A highly efficient designing and synthesis of an aryl-substituted carbazole-based fluorescent material ( MeOCbzBP) has been carried out via tandem carbon-carbon (C-C)/carbon-nitrogen (C-N) bond formation by multiple Suzuki couplings and Cadogan cyclization followed by C-N cross-couplings. Various organic solvents have been used to investigate photophysical, solvatofluorochromism, and photoluminescence characteristics of MeOCbzBP. The MeOCbzBP showed a reasonable redshifted absorption in UV region and photoluminescence enhancements in tetrahydrofuran/water mixtures. Furthermore, we also employed various theoretical functions to optimize the molecule both in the ground and excited states. A well-known density functional theory was employed in a solvent phase with B3LYP/6- 31G(d) level of theories. We believe that the MeOCbzBP will provide a better platform to investigate the novel applications in the field of medicinal chemistry and chemical biology. [ABSTRACT FROM AUTHOR]

Novel 6 H -cyclohepta[ c ]furan derivatives possessing aryl groups on 1,3-position were synthesized, and their photophysical behavior were investigated. 1,3-Diphenyl-5,7-difomyl derivative showed solvatochromism. As the electron donating ability at 1,3-positions and the electron withdrawing ability at 5,7-positions increased, the absorption and emission wavelengths were bathochromically shifted. Theoretical calculations revealed that their photophysical behaviors are reproduced. [ABSTRACT FROM AUTHOR]

This paper reports on the effect of a semifluorinated alkyl side chain for achieving a self-organized nanostructure to facilitate the efficient charge carrier transport. So far, semifluorinated alkyl side chains have rarely been introduced into semiconducting polymers, despite their interesting properties such as hydrophobicity, thermal stability, and solvent resistance, as well as self-organization. Herein, this study synthesizes the semifluorinated alkyl chain introduced poly(3-dodecylthiophene), SFA-P3DT, and demonstrates that self-organization of SFA-P3DT is intensely induced in nonfluorous solvent by the so-called fluorophobic effect, resulting in the formation of nanofibrillar structure. In presence of the semifluorinated alkyl side chain, organic thin film transistor (OTFT) devices exhibit the improved charge carrier mobility than that of poly(3-dodecylthiophene) with hydrocarbon alkyl chain. Moreover, higher charge carrier mobility can be obtained from the nonfluorous solvent, in comparison to the fluorous solvent, confirming the crucial role of fluorophobic effect. These observations suggest that the introduction of semifluorinated alkyl chains into a conjugated polymer may enhance the performance of OTFTs through the development of a well-ordered nanostructure via self-organization by fluorophobic effect, which, in turn, facilitates the efficient charge carrier transport. [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization two coumarin-based fluorescence probes, N′-{[7-(diethylamino)-2-oxo-2H-chromen-3-yl]carbonyl}pyridine-3-carbohydrazide ( 3) and N′-benzoyl-7-(diethylamino)-2-oxo-2H-chromene-3-carbohydrazide ( 4), proposed as a novel fluorescent chemosensor. The two probes designed showed an instant turn-off fluorescence response to Cu over other metal ions in ethanol-water mixture based on intramolecular charge transfer (ICT). It was found that pyridine-analogue coumarin is highly selective and sensitive sensor for Cu. The 3 sensor coordinates Cu in 1:1 stoichiometry with a binding constant, K = 5.22 M and the detection limit was calculated 1.97 × 10 M. [ABSTRACT FROM AUTHOR]

Biothiol compounds, commonly involving cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) are of wide range in mammalian cells for maintaining the stability of their internal environments. Due to their special significance in physiology and pathology for human, development of fluorescence probes for selective and sensitive detection of thiols under physiological conditions has attracted great interest. Compared to conventional fluorescent probes, near-infrared (NIR) fluorescent probes possess unique advantages for tracing molecular processes in vitro and in vivo. In this report, we designed and synthesized a novel NIR fluorescent probe DCM-NBD , which employed dicyanomethylene-4 H -pyran (DCM) derivatives as the NIR fluorophore and nitrobenzoxadiazole (NBD) as the response group via ether linkage. It exhibited satisfactory selectivity and sensitivity to differentiate between Cys/Hcy and GSH by dual fluorescence signals. Moreover, the probe DCM-NBD showed admirable imaging capability in living cells and animals with low cytotoxicity. [ABSTRACT FROM AUTHOR]