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2-(5-Arylpyridine-2-yl)-6-(het)arylquinoline-based "push-pull" fluorophores were synthesized by means of the heterocyclization reaction between the corresponding isonitrosoacetophenone hydrazones and 6-bromoquinoline-2-carboxaldehyde followed by an aza-Diels-Alder/Suzuki cross-coupling reaction sequence. The optical properties of the obtained fluorophores were studied and the non-linear optic behavior for the two most representative ones were confirmed based on the solvatochromic experiments. • 2-(5-Arylpyridin-2-yl)-quinolines were synthesized as "push-pull" fluorophores. • "1,2,4-Triazine methodology" was used for synthesis of the fluorophores. • Photophysical properties were studied. • The UV/Vis absorption and fluorescence spectra were investigated. [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 It is an effective and precise strategy to design the fluorescence probe for Hg2+ based on a new specific reaction. A novel turn-on fluorescent probe, 4-{2-[4-(2-Mercapto-benzoyloxy)-phenyl]-vinyl}-1-methyl-pyridinium[ e ]iodide (MBPVP) for Hg2+ was developed. The mechanism was based on Hg2+-mediated ester hydrolysis to release the fluorophore, 4-[2-(4-Hydroxy-phenyl)-vinyl]-1-methyl-pyridinium[ e ]iodide, which showed outstanding intramolecular charge transfer (ICT) and the yellow-green fluorescence were observed. The turn-on probe showed rapid response time, outstanding selectivity and sensitivity for Hg2+ over other metal ions in 100% PBS buffer (pH = 7.4). The linear range was 2–16 µM and the detection limit was 6.5 nM. Furthermore, MBPVP was used to determine Hg2+ in real samples and in the solid state. Graphical abstract fx1 Highlights • A turn-on fluorescence probe (MBPVP) for Hg2+ based on new specific reaction was developed. • MBPVP showed rapid response time, high selectivity and sensitivity in 100% aqueous solution. • The probe was applied in water samples and in the solid state. [ABSTRACT FROM AUTHOR]

Abstract Low-cost and nontoxic fluorescent reagents are important for on-site analysis performed by non-professionals. In this work, a cheap and widely available food additive, caramel was used as an effective fluorescence reagent for the sensitive detection of 2,4,6-trinitrophenol (TNP), 2,4-dinitrophenol (DNP) and 4-nitrophenol (4-NP). Through a simple dialysis, fluorescent components of a commercial caramel were harvested with a yield as high as 60%. The structural characterization demonstrated that the fluorescent components were dehydrated oligomers of carbohydrates. Their fluorescence can be quenched by these nitrophenols. The quenching mechanism was speculated as inner filter effect. At pH 8, a linear range of 0.2–22 μM and a detection limit of 90 nM could be achieved for TNP. Based on the difference of their quenching efficiency at different pHs, TNP, DNP and 4-NP can be simultaneously determined by solving the linear equations obtained at pH 3, 5 and 8. Successful detection of these nitrophenols in the water and soil samples was performed with relative standard deviations of 1.1–5.9% and recoveries of 95–108% of spiked standards. Graphical abstract fx1 Highlights • Fluorescent components were isolated from caramel through dialysis in high yield. • The fluorescent components are dehydrated oligomers of carbohydrates. • Simultaneous detection of nitrophenols in water and soil samples was achieved. [ABSTRACT FROM AUTHOR]

Abstract A dual-functional fluorescent probe based on coumarin fluorophore for monitoring ClO− and Cu2+ was synthesized and characterized. The identification mechanisms for ClO− and Cu2+ induced different colorimetric and ratiometric changes. ClO− caused a colorimetric change from yellow to colorless and 120 nm blue-shifted emission spectra from red to blue. Besides, Cu2+ induced a remarkable fluorescence quenching behavior and 36 nm blue-shifted absorption spectra accompanied by the color change from yellow to luminous yellow. As expected, Probe 1 displayed excellent selectivity and sensitivity for detecting ClO− and Cu2+ over other competing ions in their respective systems. The limits of detection for ClO− and Cu2+ were 24.62 nM and 0.39 nM, respectively. The recognition mechanisms were proved by 1H NMR, mass spectrum and theoretical calculations. More importantly, the reversibility of Cu2+ could be applicable to rapid quantification for ClO−/Cu2+. Thus, the strategy for sensing ClO−/Cu2+ was carried out, which revealed broad applications of Probe 1 in multiple actual water and biology. Graphical abstract Unlabelled Image Highlights • A novel coumarin-based fluorescent probe for multiple ions was achieved. • The probe can distinguish ClO− and Cu2+ in different mixed solutions by adjusting the cyclic reversibility of Cu2+. • The probe showed rapid responses for ClO− and Cu2+ in multiple real water with high sensitivity and selectivity. • The probe can be used to monitor exogenous ClO− and Cu2+ in organisms. [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]

Abstract N -Ethoxycarbonylpyrene- and perylene thioamides were used as building blocks in the synthesis of a variety of fluorescent dyes bearing thioimidate, 4-hydroxythiazolyl, 4-methoxythiazolyl and thiazole-4-one moieties, and an ester function. The synthesized compounds in DMSO solutions display fluorescence in the range of 412–672 nm with quantum yields 0.1–0.88. 2-(Pyrene-1-yl)-5-ethoxycarbonyl-4-hydroxythiazole and 2-(perylene-3-yl)-5-ethoxycarbonyl-4-hydroxythiazole show dual fluorescence resulting from the excitation of the neutral fluorophore and the corresponding enolate anion formed via excited state proton transfer (ESPT). As a result of ESPT the former fluorophore emits white light (CIE coordinates: 0.33, 0.36). The pyrenyl and perylenyl substituted 5-ethoxycarbonyl-5-methyl-(5H)-thiazole-4-ones displayed the highest emission efficiency (Φ F ∼0.9) and emission maxima at 503 nm and 626 nm, respectively. The observed solvatochromism suggests that in this case emission originates from intramolecular charge transfer (ICT) excited states. Highlights • Thioimidates, 4-hydroxythiazoles, their salts and thiazol-4-ones bearing pyrenyl and perylenyl groups at C-2 were synthesized. • The synthesized compounds emit fluorescence covering practically the entire visible region. • The synthesized 4-hydroxythiazoles in DMSO display dual fluorescence resulting from excited state proton transfer (ESPT). • As a result of ESPT pyrenyl-substituted 4-hydroxythiazole emits white light (CIE chromaticity coordinates: 0.33; 0.36). • The synthesized thiazol-4-ones proved very efficient emitters (Φ F ∼0.9 in DMSO) with λ max at 503 nm and 626 nm, respectively. [ABSTRACT FROM AUTHOR]

Abstract We present a lysosome-targetable and ratiometric fluorescent probe, TJ2 , for visually monitoring exogenous and endogenous HOCl in living cells by using a built-in S atom within the π-extended rhodamine fluorophore as a pH-independent recognition site. Based on the oxidation-promoted intramolecular charge transfer processes, TJ2 demonstrates fast ratiometric fluorescence response, excellent selectivity, and high sensitivity (2.3 nM) toward HOCl. Furthermore, TJ2 is highly lysosome-targetable, which could be used for ratiometric monitoring of the levels of HOCl in lysosomes. Graphical abstract A ratiometric lysosome-targetable fluorescent probe has been designed and synthesized for the sensitive and selective detection of HOCl. Image 1 Highlights • A ratiometric probe TJ2 has been synthesized for lysosomal HOCl imaging. • The probe showed fast fluorescence response, excellent selectivity, and high sensitivity (2.3 nM) toward HOCl. • The probe could be used for ratiometric monitoring of the level of lysosomal HOCl in living cells in real time. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The synthesis of 3-imino-3 H -xanthene-6-amine dye (pyronin) was revisited. • The orange-red emitting silicon analog (Si-pyronin) was prepared for the first time. • Both compounds exhibit outstanding fluorescence properties in aqueous solution. • Aqueous stability of fluorogenic Si-pyronin dye only at pH < 5. • Novel fluorogenic (Si-)pyronin substrates for detection of penicillin G acylase. Abstract To expand the range of primary aniline fluorophores available and suitable for the design of fluorogenic protease probes, the synthesis of 3-imino-3 H -xanthen-6-amine (known as pyronin) and its silicon analog (Si-pyronin) was explored and presented here. A comprehensive photophysical study of these two fluorescent anilines, confirms the effectiveness of the heteroatom-substitution approach (O → SiMe 2) to yield dramatic red-shifts in absorption and fluorescence maxima of the xanthene scaffold (+85 nm). However, it also revealed its adverse effect on the hydrolytic stability of the Si-pyronin, especially at physiological pH. The pro-fluorescent character and utility of these two fluorogenic (hetero)xanthene dyes are also proved by the preparation and in vitro validation of activatable fluorescence "turn-on" probes for penicillin G acylase (PGA). [ABSTRACT FROM AUTHOR]

Abstract: Reagents to visualize and localize neuraminidase activity would be valuable probes to study the role of neuraminidases in normal cellular processes as well as during viral infections or cancer development. Herein, a new class of neuraminidase‐imaging probes that function as proximity ligation reagents by releasing a highly reactive fluorophore that tags nearby cellular material is described. It is further demonstrated that it is possible to create an influenza virus‐specific reagent, which can specifically detect influenza virus infections in mammalian cells. These reagents have potential use as specific histological probes independent of viral antigenicity and, therefore, offer some advantages over commonly used anti‐neuraminidase antibodies. [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]

Objective: It is difficult to identify the gold nanoparticles (AuNPs) intracellularly due to their non-fluorescent nature. Although gold can quench the fluorescence of any fluorophore, hence it is also difficult to combine gold with a fluorophore such as a semiconductor quantum dots (QDs). The aim of this study was to prepare a single fluorescent stable AuNPs combined with QDs (QDs-Au-NPs) which can be easily detected intracellularly. Methods: QDs-Au-NPs were prepared via a simple one-step process through controlling the spacing between them using polyethylene glycol (PEG) as space linker in the form of PEGylated QDs. Furthermore, the applicability of this system was evaluated after coating the particles with somatostatin citrate, SST, to active target somatostatin receptors (SSTRs), and identification of the internalized particles via confocal laser scanning spectroscopy. Results: The results showed that the produced Au shell has a thickness of 2.0 ± 0.2nm and QDs-Au-NPs showed the same fluorescence intensity compared to the unmodified QDs. Additionally, a stable monodisperse QDs-Au-NPs coated with SST were prepared after coating with 11-Mercaptoundecanoic acid. Moreover, cellular uptake study in Human Caucasian breast adenocarcinoma cell lines showed that QDs- Au-SST-NPs could be detected easily using the confocal microscope. In addition, they showed a significant (p≤.05) internalization per cell compared to untreated QDs-Au-NPs as detected by flow cytometry. Conclusion: It could be concluded that the produced QDs-Au-NPs has a strong fluorescence property like QDs which enable them to be easily detected after cells internalization. [ABSTRACT FROM AUTHOR]

Surgical methods guided by exogenous fluorescent markers have the potential to define tissue types in real time. Small molecule dyes with efficient and selective renal clearance could enable visualization of the ureter during surgical procedures involving the abdomen and pelvis. These studies report the design and synthesis of a water soluble, net neutral C4′- O -alkyl heptamethine cyanine, Ureter-Label (UL)-766, with excellent properties for ureter visualization. This compound is accessed through a concise synthetic sequence involving an N - to O -transposition reaction that provides other inaccessible C4′- O -alkyl heptamethine cyanines. Unlike molecules containing a C4′- O- aryl substituent, which have also been used for ureter visualization, UL-766 is not reactive towards glutathione and the cellular proteome. In addition, rat models of abdominal surgery reveal that UL-766 undergoes efficient and nearly exclusive renal clearance in vivo . In total, this molecule represents a promising candidate for visualizing the ureter during a variety of surgical interventions. [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]

In this study, we report on the syntheses of novel angular fused azaacenes. For this purpose, the synthesis of the bis-diamine 2 (TABEF) could be shortened and optimized. The condensation reaction of 2 with different types of 1,2-diketones yielded new azaacene derivatives of types 10, 11 and 12. Analogously, 2 was cyclized with thionyl chloride to give the piazthiol derivative 13. The optical and electrochemical properties of all new compounds were investigated by UV/Vis absorption, fluorescence emission spectroscopy and cyclovoltammetric measurements. [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]

New scaffolds of sulfonamido-chromone derivatives recently synthesized were found to be effective fluorescent sensors for fluoride anion. This new class of fluorophore showed a blue shift in the emission spectra upon addition of various equivalents of fluoride. These compounds also exhibit excellent selectivity for the fluoride anion via a deprotonation process. They were also shown to have a detection limit of F − down to 0.5 ppm. [ABSTRACT FROM AUTHOR]

Pericentromeric heterochromatin plays important roles in controlling gene expression and cellular differentiation. Fluorescent pyrrole-imidazole polyamides targeting murine pericentromeric DNA (major satellites) can be used for the visualization of pericentromeric heterochromatin foci in live mouse cells. New derivatives targeting human repeated DNA sequences (α-satellites) were synthesized and their interaction with target DNA was characterized. The possibility to use major satellite and α -satellite binding polyamides as tools for staining pericentromeric heterochromatin was further investigated in fixed and living mouse and human cells. The staining that was previously observed using the mouse model was further characterized and optimized, but remained limited regarding the fluorophores that can be used. The promising results regarding the staining in the mouse model could not be extended to the human model. Experiments performed in human cells showed chromosomal DNA staining without selectivity. Factors limiting the use of fluorescent polyamides, in particular probe aggregation in the cytoplasm, were investigated. Results are discussed with regards to structure and affinity of probes, density of target sites and chromatin accessibility in both models. [ABSTRACT FROM AUTHOR]

A fluorescent probe for protease sensing and based on the “covalent-assembly” principle is reported. The basic rational for this unusual class of chemodosimeters proposed by the Anslyn and Yang groups entails the synthesis of non-fluorophore caged precursors full-stable and reactive towards the targeted analyte. Unlike the first generation of protease-sensitive “covalent-assembly” type probes recently published by ourselves ( Org. Biomol. Chem. 2017 , 15 , 2575–2584), the availability of dicyanomethylidenyl and enzyme-labile phenylacetamide moieties within the core structure of mixed bis-aryl ether 2 enables its rapid conversion into a fluorescent pyronin dye at physiological pH and upon activation with penicillin G acylase (PGA). This is real progress towards the practical implementation of this ingenious activation mechanism to the detection of enzymes in their native environment ( in cellulo or in vivo ). [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]

New fluorescent thiophenyl group containing oxazol-5-one fluorophores of 3a (4-(3-thiophenylmethylene)-2-phenyloxazol-5-one), 3b (4-(3-thiophenylmethylene)-2-(4-tolyl)oxazol-5-one) and 3c (4-(3-thiophenylmethylene)-2-(4-nitrophenyl)oxazol-5-one) were synthesized and characterized. The newly synthesized oxazol-5-ones absorption and fluorescence characteristics were studied in some solvents of varying polarities. The heterocyclic chromophores were fluorescent, with two of them, 3a and 3b, emitting blue light, whilst the other one, 3c, emitting green light. The emission maxima of the derivatives varied between 415 and 572 nm according as the extent of conjugation and solvent polarity. As solvent polarity increased, 3c derivatives emission spectra displayed a large bathochromic shift, which revealed the considerable change of the dipole moment of the fluorescent structure because of an intramolecular charge transfer interaction. Furthermore, oxazolones polymerization ability via the thiophenyl group linked to the oxazol-5-one heterocycle showed that copolymerization of 3a was achieved, but homopolymerization was not observed. [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]

A near-infrared fluorescent probe ( NRL ) for lysosomal pH was presented by integrating 4-(2-aminoethyl)morpholine moiety, a lysosome-targetable group, into the rhodamine derivative. The addition of H + led to significant fluorescence intensity increase at 739 nm, thus enabling it to monitor pH changes at weakly acidic pH. NRL showed negligible response to common species and short response time. Furthermore, the probe was successfully applied in living cells, and the results indicated that the probe could target lysosomes and detect lysosomal pH. We believe that NRL had great potential as a practical tool for lysosomal pH biology. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis and photophysical investigation of a novel 1,8-naphthalimide fluorophore containing 2-amino-1,3,4-thiadiazole fragment at C-4 position. Absorption and fluorescence characteristics of the dye as a function of pH were investigated in water/ethanol (1:1, v/v) solution. It was found that the synthesized 1,8-naphthalimide did not show significant changes in the emission properties in a wide pH range. Furthermore the ability of the synthesized compound to detect cations was evaluated by the changes in its fluorescence intensity in the presence of metal ions (Co2+, Cu2+, Fe3+, Ni2+, Pb2+, Cd2+, Zn2+ and Hg2+). Only Hg2+, among the tested metal ions, was efficiently detected due to the aggregation caused quenching process. The results obtained indicate the potential of the novel compound acting as a fluorescent "onoff" switch for selective determination of Hg2+ in a wide pH window. [ABSTRACT FROM AUTHOR]

New bifluorophore based on 2-aminodimethylterephthalate as a donor and 3-aminobenzanthrone as an acceptor of excitation energy was synthesized and characterized. The s-triazinyl ring as the spacer between two parts was used. A new monofluorophore 2-aminodimethylterephthalate derivative was synthesized as a reference compound and investigated as well. Absorption, emission spectra and fluorescence quantum yields of synthesized compounds were measured. Due to the efficient donor-acceptor energy transfer (89 %) the acceptor fluorescence of the system, excited in the maximal absorption of the donor fluorophore, was enhanced more than 5 times with respect to the fluorescence intensity of the reference 3-aminobenzanthrone. The sensor activity of mono and bifluorophore toward protons as cations and hydroxide as anions in DMF/water was studied by monitoring the changes of the fluorescence intensity. Due to internal charge transfer (ICT) at monofluorophore and the energy transfer (ET) at bifluorophore, the designed compounds were able to act as a pH-probe via an "off-on" fluorescence sensing mechanism. [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]

Prostate-specific membrane antigen (PSMA) is an important biological target for therapy and diagnosis of prostate cancer. In this study, novel multivalent PSMA inhibitors with glutamate-urea-lysine structures were designed to improve inhibition characteristics. Precursors of the novel inhibitors were prepared from glutamic acid with di- tert -butyl ester. A near-infrared molecular dye, sulfo-Cy5.5, was introduced into the precursors to generate the final PSMA fluorescent inhibitors, compounds 12 – 14 , to visualize prostate cancer. Biological behaviors of the inhibitors were evaluated using in vitro inhibition assays, in vivo fluorescent imaging, and ex vivo biodistribution assays. K i values from inhibition studies indicated that dimeric inhibitor 13 with a glutamine linker showed approximately 3-fold more inhibitory activity than monomeric inhibitor 12 . According to other biological studies using a mouse model of prostate cancer, dimeric inhibitor compounds 13 and 14 had higher tumor accumulation than the monomer. However, glutamine-based dimeric inhibitor 13 showed lower liver uptake than dimeric inhibitor 14 , which had a benzene structure. Thus, these studies suggest that glutamine-based dimeric inhibitor 13 can be a promising optical inhibitor of prostate cancer. [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]

A practical synthesis of a variety of λ5-phosphinines, which show distinct fluorescence both in solution and solid state, is described. Both C4-selective electrophilic substitutions and the following conversions realized an easy preparation of a wide range of derivatives having several substituents for electronic modification, which provides the potential for fine-tuning of the photophysical properties. [ABSTRACT FROM AUTHOR]

Citrate is an important intermediate in the citric acid cycle, a vital metabolic pathway for animals, plants and bacteria. It is of great significance to detect its levels in human beings because several diseases may cause the abnormal of citrate. In this paper, a new turn-on fluorescent sensor (TPE-Py) using the classic tetraphenylethylene (TPE) as the aggregation-induced emission (AIE) fluorophore and bipyridinium-based amides as the recognition receptor has been synthesized for the detection of citrate. The probe exhibits good selectivity and sensitivity to citrate with a relatively low detection limit (1.0 × 10 −7 M). The enhancement of the fluorescence is relevant with the AIE property based on the complexation of TPE-Py with citrate caused by the hydrogen bonding and electrostatic interactions between the bipyridinium diamides and citrate, which has been proved by 1 H NMR and mass spectra titration, scanning electronic microscope and dynamic light scattering analyses. More importantly, the quantification of citrate in artificial urine may develop TPE-Py fluorometric probe for the citrate detection in real biosystems. [ABSTRACT FROM AUTHOR]

Two novel fluorescent probes ( C1, C2), comprising a coumarin moiety as fluorophore and a pair of dithiocarbamates as recognition sites, were designed and synthesized as fluorescent probes for Ag. The probes exhibited high selectivity for Ag with fluorescence enhancement (FE) in CHCN/4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (1:9, v/v, pH 7.38); the selectivity was not affected by other metal ions. The binding ratio of C2-Ag complex was determined to be 1:1 according to the Job plot and mass spectroscopy (MS) data. The association constant K of Ag with C2 was 1.6 × 10 M. These probes could be applied for monitoring of Ag in aqueous solution in the pH range of 5.0-8.0, with calculated detection limit of 0.27 μM. [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]

The synthesis of phospholyl(borane) amino acids was stereoselectively achieved by reaction of phospholide anion with iodo α-amino ester derived from L-aspartic acid or L-serine, followed by in situ complexation with borane. Phospholyl(borane) amino acids are easy to store and can be subjected to direct transformation into the corresponding free phospholyl, gold complex, oxide or sulfur derivatives as well as phospholinium salts, thus offering a variety of side chains. After selective deprotection of carboxylic function or amine, C- or N-peptide coupling with an alanine moiety proved the possible incorporation into peptides. Such phospholyl amino acid and peptide derivatives exhibit fluorescent properties with a large Stokes shift (160 nm) and fluorescence up to 535 nm, depending on the phosphole aromaticity and the chemical environment. These phospholyl(borane) amino acids constitute a new class of unnatural amino acids useful for structure-activities relationship studies and appear to be promising fluorophores for the development of labeled peptides. [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]

Controlling the traffic of molecules and ions across membranes is a critical feature in a number of biologically relevant processes and highly desirable for the development of technologies based on membrane materials. In this paper, ion transport behavior of hybrid lipid/polymer membranes was studied in the absence and presence of ion transfer agents. A pH-sensitive fluorophore was used to investigate ion (H + /OH − ) permeability across hybrid lipid/polymer membranes as a function of the fraction of amphiphilic block copolymer. It was observed that vesicles with intermediate lipid/polymer ratios tend to be surprisingly more permeable to ion transport than the pure lipid or pure polymer vesicles. Hybrid vesicle permeability could be further modulated with valinomycin, nigericin, or gramicidin A, which significantly expedite the dissipation of externally-imposed pH gradients by facilitating the transport of the rate-limiting co-ions ( e.g. K + ) ions across the membrane. For gramicidin A, ion permeability decreased with increasing polymer mole fraction, and the method of introduction of gramicidin A into the membrane played an important role. Strategies to incorporate biofunctional molecules and facilitate their activity in synthetic systems are highly desirable for developing artificial organelles or other synthetic compartmentalized structures requiring control over molecular traffic across biomimetic membranes. [ABSTRACT FROM AUTHOR]

A thioether-functionalized probe with a dipodal pyrene-sulfonamide fluorophore (probe 1 ) was synthesized for the selective and sensitive detection of Hg 2+ in aqueous solutions. In addition, a probe with a monopod pyrene-sulfonamide unit was prepared (probe 2) . Among various metal ions, these two probes appeared to selectively bind to Hg 2+ at a 1:1 ratio, with a stronger association of probe 1 than probe 2 , as evidenced by titration experiments. The green emission displayed by probe 1 was completely quenched by the coordination of Hg 2+ to sulfur ( ON-OFF ), presumably via energy transfer from the pyrene fluorophore to the [sulfur-Hg 2+ ] unit. The limit of detection (LOD) was 1 nM (0.22 ppb), one of the lowest values obtained so far. Furthermore, the in situ -prepared [ 1 +Hg 2+ ] complex continued to be utilized to selectively detect dithiouracil (DTU) via an “ OFF-ON” mechanism among diverse biomolecules, along with an LOD of 20 nM. Thus, probe 1 alone or together with Hg 2+ allowed the cascade detection of Hg 2+ and DTU with high selectivity and ultra-sensitivity. The current study indicates that probe 1 not only serves as an ‘INHIBIT and AND’ logic gate, but also works as an “ ON−OFF−ON” molecular switch triggered by the sequential addition of Hg 2+ and DTU. [ABSTRACT FROM AUTHOR]

A pyrene based chemosensor was designed and synthesized. The pyrene fluorophore was connected with a pyridine unit through a Schiff base structure to give the sensor ( L ). L was tested with a variety of metal ions and exhibited high colorimetric selectivities for Cu 2+ and Fe 3+ over other ions. Upon binding with Cu 2+ or Fe 3+ , L showed an obvious optical color change from colorless to pink for Cu 2+ or orange for Fe 3+ over a wide pH range from 3 to 12. Moreover, the fluorescence of L at 370 nm decreased sharply after bonding with Fe 3+ , while other metal ions including Cu 2+ had no apparent interference. Thus, using such single chemosensor, Cu 2+ and Fe 3+ can be detected independently with high selectivity and sensitivity. The limits of detection toward Cu 2+ and Fe 3+ were 8.5 and 2.0 μM, respectively. DFT calculation results also proved the formation of stable coordination complexes and the phenomenon of fluorescence quenching by Fe 3+ . Furthermore, L was also successfully used as a bioimaging reagent for detection of Fe 3+ in living cells. [ABSTRACT FROM AUTHOR]

Three ( E / Z )-diastereoisomers, based on pyrrolo[2,3- b ]quinoxaline system as fluorophore and containing: 2-thienylmethyl ( 1 ), bis (2-thienylmethyl)-2-aminoethyl ( 3a ), bis (2-thienylmethyl)-3-aminopropyl ( 3b ) groups as substituents, were synthesized and characterized by X-ray structural analysis, PXRD, NMR, UV–Vis as well as fluorescence. These compounds are non-fluorescent in acetonitrile solution, however, they exhibit aggregation induced emission enhancement (AIEE) upon water addition and in solid state. X-ray structural analysis revealed that molecules with 2-thienylmethyl and bis (2-thienylmethyl)-2-aminoethyl groups form dimers and π-stacks through π-π interactions between anitiparallel oriented pyrroloquinoxaline cores with interplanar distances 3.45 Å and 3.20 Å, respectively. Conformation of bis (2-thienylmethyl)-3-aminopropyl group is imposed by incorporated DMSO- d 6 solvent molecule and weak intermolecular S-π and CH-π interactions, that prevents π-π interaction between fluorophore cores. The correlation between crystal structure and fluorescent properties of synthesized molecules was discussed. The DFT calculations were performed to rationalize the differences between considered systems. [ABSTRACT FROM AUTHOR]

In 2003, we successfully created the first fluorescent polymeric thermometer by combining a thermo-responsive polymer and an environment-sensitive (polarity and hydrogen bonding-sensitive) fluorophore. Its high sensitivity to temperature variation and high hydrophilicity, even under conditions of high ionic strength, enabled intracellular temperature measurements. Along with the progress of our research projects, the development of new luminescent molecular thermometers and the establishment of novel methods for measuring intracellular temperature have matured in this field. In this Feature Article, we summarize the background and history of intracellular temperature measurements using fluorescent polymeric thermometers based on studies performed in our laboratory and the relationship between our methods and those of other eminent research groups. Future research directions regarding intracellular temperature measurements are also discussed. [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]

Starting from 3-alkoxy-2-aryl-substituted pyrroles and aromatic aldehydes, a collection of new dipyrrins was prepared. Under the standard conditions of Treibs, these were converted into the corresponding boron dipyrrins (BODIPYs). Compounds of this type with alkoxy groups at C-3 position of both pyrrole subunits are new and hence the photophysical properties of this collection of novel dipyrrins and BODIPY dyes were investigated. The dipyrrins show absorption maxima up to 596 nm and emissions of up to 677 nm. For the BODIPY series a remarkable effect of the alkoxy groups was identified, resulting in red shifts for absorptions and emissions. The compound substituted with two 2-thien-2-yl groups and a meso-C6F5 substituent shows an absorption maximum at 725 nm and emits at 754 nm and thus is a new representative of a near-IR BODIPY dye related to certain aza-BODIPYs. Our results demonstrate the influence of the alkoxy groups on the spectroscopic data and reveal the potential of 3-alkoxy-2-aryl-substituted pyrroles for the design of new fluorophores. [ABSTRACT FROM AUTHOR]