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Photoresponsive fluorescent compounds have been widely used to prepare the encryption inks for modern information security. In this study, a photoresponsive fluorescent material based on dithienylethene DTE-PIO4 was synthesized by oxidizing the two sulfur atoms to sulfones. Its solution presented a distinctive fluorescence switching performance when compared with the traditional "turn-off" mode fluorescent dithienylethene, while irreversible "turn-off" fluorescence switching was observed in PMMA films and solid state upon exposure to 254 nm UV light. Remarkably, the PMMA ink was successfully prepared by incorporation with DTE-PIO4, which indicated the great potential in the fields of optical information storage and ink printing. Further research on information encryption has also been demonstrated through the blending of DTE-PIO4 with DTE-PI in PMMA medium. [ABSTRACT FROM AUTHOR]

Photochromic fluorescence switching with aggregation-induced emission (AIE) property has attracted great research interest due to their wide application potential in optical electronics and biomaterials. In this work, three novel pyrene-dithienylethene-tetra(tri)phenylethylene triads were synthesized by connecting triphenylethene (TrPE) or tetraphenylethylene (TPE) and pyrene unit via dithienlethene (DTE) bridge. Efficient photochromism and fluorescence switching were demonstrated in solution, aggregates, solid powder, and poly(methyl methacrylate) (PMMA) films under alternating irradiation with UV/visible light. The photocyclization yield of DTE-Py-3 was examined by 1H NMR spectra and calculated as 59%. Moreover, these three compounds exhibited typical AIE character in THF/water mixture, the photochromic and fluorescent switching behavior were explored in aggregated state with 90% water fraction. Furthermore, they could be utilized in application of optical information storage and ink with naked-eye color and fluorescence double channel, indicating the promising potential in anti-counterfeiting. Interestingly, DTE-Py-3 could be reversibly switched by visible light in both directions, which endowed it with the application in biological filed. Efficient photochromic fluorescence switching were demonstrated in solution, aggregated solution, solid powder, and PMMA films under alternating UV/visible light irradiation. [Display omitted] • After AIE group was grafted onto the pyrene unit, typical AIE phenomenon were achieved for the target triads. • Photochromism and fluorescence photoswitching were achieved in solution, aggregated state, PMMA films and solid powder with the alternative UV/Visible light irradiation. • The application of optical information storage and ink were demonstrated. [ABSTRACT FROM AUTHOR]

A novel ratiometric fluorescent probe ( RIM ) for HOCl was designed on imidazo[1,5 -a ]pyridine-rhodamine FRET platform. Upon addition of HOCl, the imidazo[1,5 -a ]pyridine fluorescence increased and the rhodamine fluorescence increased simultaneously. The ratios (I 585 /I 465 ) displayed brilliant HOCl-dependent performance and responded linearly to HOCl. RIM could respond to HOCl rapidly (within 20 s) with a low detection limit of 24 nM RIM also exhibited high selectivity, and low cytotoxicity. Moreover, it has been successfully applied in fluorescence imaging in living cells and the results confirmed that the probe could selectively stain lysosomes with excellent photostability. [ABSTRACT FROM AUTHOR]

A novel all-visible-light controlled photochromic dithienylethene (DTE) derivatives bearing phenanthroimidazole (PI) unit were synthesized (DTE-PI). Upon alternating irradiation with 420/540 nm light, effective photochromic and fluorescent switches were demonstrated in solution, PMMA film, single crystal and solid powder. Remarkably, multi-stimuli responsive chromism and fluorescence switches were demonstrated by modulation of protonation. The effect of adding trifluoroacetic acid (TFA) on the performance of DTE-PI were carefully investigated. Interestingly, multi-stimuli responsive chromism and fluorescent switches were achieved with good reversibility when treated with excessive TFA. Neutralization by triethylamine (TEA) could restore it to the initial state. Notably, the photoswitchable dual-mode patterning application was developed successfully. [Display omitted] • An all-visible-light triggered phenanthroimidazole-based dithienylethene was constructed. • The reversible multi-stimuli responsive photochromic fluorescent switching was achieved. • Single crystal structure was obtained and reversible photochromism and fluorescent switching behavior. • All-visible-light patterning application on a filter paper was demonstrated. [ABSTRACT FROM AUTHOR]

A series of novel 2-acyl-6-aryl substituted indolizine derivatives was synthesized by a novel tandem reaction between 4-acyl-pyrrole-2-carbaldehyde derivatives and ethyl 4-bromo-3-arylbut-2-enoate under mild conditions. The compounds were characterized using IR, 1 H NMR 13 C NMR and HRMS. The crystal structure of 7a was determined using single crystal X-ray crystallography. The absorption results showed that compounds 7a–e presented their absorption maxima at ca. 270 nm, while compounds 7f and 7g with a larger conjugation system exhibited red-shifted absorption character (ca. 280 nm). Fluorescence spectra revealed that these compounds exhibited blue fluorescence (434–456 nm) in dilute solutions and showed quantum yields of fluorescence between 0.02 and 0.39 in dichloromethane. [ABSTRACT FROM AUTHOR]

Highlights: [•] Newly synthesized 5-(aryliminomethyl)quinaldine-8-ol derivatives. [•] Trinuclear complexes of zinc 5-(aryliminomethyl)quinaldin-8-olates. [•] X-ray diffraction study on zinc complex. [•] The luminescent properties enhanced through coordination. [Copyright &y& Elsevier]

Highlights: [•] Novel 1,3,4-oxadiazole derivatives were prepared and fully characterized. [•] UV–vis absorption and fluorescence spectroscopy of all compounds were measured. [•] The minimized structures, the molecular orbital (HOMO and LUMO) energies and the orbital maps of compound 5a –g were calculated. [Copyright &y& Elsevier]

Novel imidazo[1,5-a]pyridinyl 1,3,4-Oxadiazole derivatives were synthesized and characterised by IR, H NMR and HRMS.UV-vis absorption and fluorescence properties of these compounds in different solutions showed that the maximal emission wavelength was not significantly changed in different solvents; however, maximum absorption wavelength was blue-shifted with the increase of solvent polarity. Absorption λ and emission λ was less correlated with substituent groups on benzene rings. The calculated molecular orbital correlates well with their absorption. [ABSTRACT FROM AUTHOR]

Abstract: Photoluminescence of Eu(TTA)3DPBT (TTA=thenoyltrifluoro-acetonate DPBT=2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine) in toluene and PMMA thin film are measured with excitation at 350 and 404nm, respectively, and analyzed using Judd–Ofelt theory. Under excitation at 350nm, it is found that Eu(TTA)3DPBT in toluene has a larger Ω 2 value (14.33×10−20 cm2) than that (12.70×10−20 cm2) of Eu(TTA)3Phen (Phen=1,10-phenanthroline) in the same solvent, and has a smaller Ω 2 value (12.70×10−20 cm2) in PMMA than that (Ω 2=14.09×10−20 cm2) of Eu(TTA)3Phen in PMMA. At the same time, it can be seen that under excitation at 350nm Ω 2 value of Eu(TTA)3DPBT in toluene is larger than that in PMMA. Excited by 404nm, Ω 2 of Eu(TTA)3DPBT obtained in toluene and in PMMA are the same as that excited at 350nm. The transition probability (A), emission cross-section (σ) and the fluorescence branching ratio (β) are also evaluated. The lifetime of 5D0 metastable state is measured on 350 and 404nm excitation, respectively. For the former situation, it is 455μs in toluene and 640μs in PMMA, for the latter it is 460μs in toluene and 664μs in PMMA. By comparing absorptions with excitations, it can be found that DPBT is more efficient than TTA as an energy donor. Phosphorescence spectra are also measured to estimate the lowest triplet level and analyze the energy transfer for DPBT and TTA, from which it is found that the energy transfer from TTA to DPBT occurs in the luminescent process. [Copyright &y& Elsevier]

Abstract: A series of novel substituted 1,3,4-oxadiazole derivatives containing pyrido[1,2-a]benzimidazole moiety were synthesized and characterized using FTIR, 1H NMR, 13C NMR, and HRMS. An efficient tandem reaction was employed as a key step in constructing the pyrido[1,2-a]benzimidazole moiety under very mild condition. The structure of compound 4a was established by X-ray crystallography. The UV–vis absorption and fluorescence spectral characteristics of these compounds were investigated in several solvents. Compounds 4a–i display similar absorptions, with absorption peaks ranging from 330 to 339nm in acetonitrile, while the absorption maxima of compound 4j bearing a diphenylamino group on the benzene ring is red-shifted distinctly to 377nm due to the strong electron-donating property of its substituent and extended π-conjugated system. All these target heterocyclic compounds present blue-green emissions (461–487nm) in dilute solutions and show high quantum yields of fluorescence (Ф PL=0.65−0.99) in dichloromethane. [Copyright &y& Elsevier]

Abstract: A series of novel, substituted, pyrido[1,2-a]benzimidazole derivatives were synthesized using a novel tandem annulation reaction between 2-acylbenzimidazole derivatives and 4-bromobut-2-enoic esters under mild conditions. The compounds were characterized using IR, 1H NMR, 13C NMR and HRMS; the crystal structure of 2,7,8-trimethyl-3-ethoxycarbonyl-4-phenylpyrido[1,2-a]benzimidazole was determined as orthorhombic. The absorbance and fluorescence spectra of the pyrido[1,2-a]benzimidazoles were measured in dichloromethane; an intense absorption maxima was observed at 250 nm and emission maxima were noted at 460 nm. The absorption spectra and fluorescence characteristics of the pyrido[1,2-a]benzimidazole derivatives revealed that a phenyl and a methyl group attached to the pyrido[1,2-a]benzimidazole ring markedly influenced maximum emission. [ABSTRACT FROM AUTHOR]

The interactions between pentachlorophenol (PCP) and jack bean urease were studied using UV/vis absorption, CD, fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectroscopic techniques. The fluorescence data showed that the fluorescence quenching of urease by PCP the results of the formation of a PCP-urease complex involving a hydrophobic interaction. The distance r between the donor (urease) and acceptor (PCP) was obtained from the fluorescence resonance energy transfer. The effect of PCP on the conformation of urease was analyzed using UV/vis absorption, synchronous fluorescence and three-dimensional fluorescence spectroscopic techniques. The result showed that PCP can enter into the hydrophobic pocket at the interface of urease and that the micro environments around the tyrosine and tryptophan residues were changed. [ABSTRACT FROM AUTHOR]

Abstract: The interaction between bovine hemoglobin (BHb) and Fe3O4 colloid was investigated by UV/vis absorption, FT-IR, fluorescence, resonance light scattering spectra, CD, synchronous fluorescence, and three-dimensional fluorescence spectra techniques under physiological pH 7.40. Fe3O4 effectively quenched the intrinsic fluorescence of BHb via static quenching. The process of binding Fe3O4 on BHb was a spontaneous molecular interaction procedure. The thermodynamic parameters indicate that van der Waals and hydrogen bonds, electrostatic interactions played a major role in stabilizing the Fe3O4–BHb complex. The effect of Fe3O4 on the conformation of BHb was analyzed using CD and synchronous fluorescence spectroscopy. [Copyright &y& Elsevier]

Two novel chiral fluorescence calix[4]arenes functionalized at the lower rim with diphenylethylenediamine and thiourea units were synthesized and examined for their enantioselective recognition abilities by the fluorescence and 1H NMR spectra in DMSO. The results indicate that 1 and 2 both formed a 1:1 complex with amino alcohol and exhibit good enantioselective fluorescent responses for phenylglycinol (receptor 1 KL/KD = 4.85, ΔΔG0 = - 3.90 kJ mol- 1). [ABSTRACT FROM AUTHOR]

Abstract: The interaction between paraquat (PQ) and bovine hemoglobin (BHb) was investigated using fluorescence and UV/vis absorption spectroscopy. The reactivity of the heme centers with superoxide anions formed by PQ was judged on the basis of the decrease of the Soret band. The experimental results showed that the fluorescence quenching of BHb by PQ was a result of the formation of PQ–BHb complex; static quenching was confirmed to result in the fluorescence quenching. The binding site number n, apparent binding constant K A and corresponding thermodynamic parameters were measured at different temperatures. The process of binding PQ molecule on BHb was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased. Hydrophobic and electrostatic interactions played a major role in stabilizing the complex. The effect of PQ on the conformation of BHb was analyzed using synchronous fluorescence spectroscopy. [Copyright &y& Elsevier]

Abstract: The feature of brucine binding to human serum albumin (HSA) was investigated via fluorescence and UV/vis absorption spectroscopy. The results revealed that brucine caused the fluorescence quenching of HSA by the formation of brucine–HSA complex. The hydrophobic interaction plays a major role in stabilizing the complex; the binding site number n and apparent binding constant K A, corresponding thermodynamic parameters the free energy change (ΔG), enthalpy change (ΔH) and entropy change (ΔS) at different temperatures were calculated. The distance r between donor (HSA) and acceptor (brucine) was obtained according to fluorescence resonance energy transfer. The effect of brucine on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy and UV/vis absorption spectroscopy. [Copyright &y& Elsevier]

Organic light‐emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) materials are promising for the realization of highly efficient emitters. However, severe efficiency roll‐off at high brightness still remains as a huge challenge for TADF‐based OLEDs. Herein, rod‐like orange‐red TADF emitters of 2BNCz‐PZ and 2BNtCz‐PZ with acceptor‐donor‐acceptor (A‐D‐A) configuration are developed by bearing dihydrophenazine donor and discoidal rigid boron, nitrogen‐contained polycyclic aromatic hydrocarbons acceptors. Both emitters exhibit hybrid long‐range/short‐range charge‐transfer excitation for small singlet‐triplet energy splitting, short delayed lifetime, and high photoluminescence quantum yield, leading to fast singlet radiation rate over 107 s−1 and fast reverse intersystem crossing rate over 106 s−1. Furthermore, a horizontal emitting dipole orientation factor over 90% is realized. The optimized orange‐red OLED based on 2BNtCz‐PZ presents a maximum external quantum efficiency (EQE) of 31.0% and a slight EQE roll‐off to 22.2% at 1 000 cd m−2 with emission peak over 600 nm. In addition, the single‐emitting layer white OLEDs achieve a maximum EQE of 30.6% due to the use of these orange‐red dopants with intense charge‐transfer absorption band. This work reveals the potential of the rod‐like A‐D‐A configuration for constructing highly efficient orange‐red TADF emitters with low‐efficiency roll‐off. [ABSTRACT FROM AUTHOR]

Achieving deep blue thermally activated delayed fluorescent (TADF) materials with narrow emission still remains a challenge. Herein, two deep blue TADF emitters DCBTRZ and PPCTRZ were designed and synthesized by directly using host materials, 1,4-di(carbazol-9-yl)benzene (DCB) and 2-[4-(9H-carbazol-9-yl)phenyl]-1-phenyl-1H-phenanthro[9,10-d]imidazole (PPC) as donors, and 2,4,6-triphenyl-1,3,5-triazine (TRZ) as an acceptor. The two emitters have typical TADF properties. Both of them can emit deep blue fluorescence with a very narrow full-width at half-maximum (FWHM) of 42 nm in toluene. The photoluminescence quantum yields (PLQYs) of DCBTRZ and PPCTRZ are 39.6% and 38.2% in doped films, respectively. Devices based on DCBTRZ and PPCTRZ achieve deep blue emission (440 and 442 nm) with maximum external quantum efficiencies (EQEmax) of 6.68% and 6.55%, respectively. Meanwhile, they exhibit very high color purity. The CIEy and FWHM of devices employing DCBTRZ and PPCTRZ are 0.059/0.063 and 56/54 nm, respectively, meeting the standard of NTSC for deep-blue emitters, which indicates excellent application prospects in displays. The results suggest that this strategy for developing deep blue TADF materials with narrow emission and CIEy < 0.06 directly employing host materials as donors is feasible and effective. [ABSTRACT FROM AUTHOR]

The traditional preparation method of ratiometric probes faces challenges such as cumbersome preparation and low sensitivity. Thus, there is an urgent need to provide a simple method of preparing a highly sensitive ratiometric probe. Here, Eu3+-doped zinc-based organic framework (Eu/Zn-MOF) was prepared through hydrothermal method for the detection of tetracycline analogs (TCs). Under the same excitation conditions, the probe can simultaneously display valuable fluorescence and second-order scattering signals. The developed probe enabled specific identification and fast detection (1 min) of TCs, including tetracycline, oxytetracycline, doxycycline, and chlortetracycline. The linear detection ranges of tetracycline, oxytetracycline, doxycycline and chlortetracycline were respectively 100 nM - 200 μM, 100 nM - 200 μM, 98 nM - 195 μM, and 97 nM - 291 μM, and the corresponding detection limits were respectively 15.79 nM, 20.83 nM, 15.31 nM, and 28.30 nM. The developed sensor was successfully applied to detect TCs in real samples, and the recovery rate was from 92.54 % to 109.69 % and the relative standard deviation was from 0.04 % to 2.97 %. Moreover, the heterometallic Eu/Zn-MOF was designed as a ratiometric neuron for Boolean logic computing and information encryption based on the specific identification of TCs. As a proof of concept, molecular steganography was successfully employed to encode, store, and conceal information by transforming the specific identification patterns of Eu/Zn-MOF into binary strings. This study is anticipated to advance the application of metal-organic frameworks in logic detection and information security, and bridging the gap between molecular sensors and the realm of information. Heterometallic Eu/Zn-MOF-based ratiometric sensing platform was developed for identification of tetracycline analogs based on fluorescence/second-order scattering strategy, and its molecular informatization applications. [Display omitted] • A simple method for the preparation of novel ratiometric probes was provided. • A rapid and specific tetracycline analogs (TCs) sensor was developed. • The sensor had a wide linear detection range. • The developed sensor was successfully utilized to detect TCs in real samples. • Developing an artificial ratiometric neuron for encrypting a specific information. [ABSTRACT FROM AUTHOR]

Abstract: The interaction between Cr2O7 2− and human serum albumin (HSA) was investigated using fluorescence, UV/vis, FT-IR, CD spectroscopy, and molecular modeling method. The experimental results showed that the fluorescence quenching of HSA by Cr2O7 2− is a result of the formation of HSA–chromium(VI) complex; static quenching was confirmed to result in the fluorescence quenching. The corresponding thermodynamic parameters showed that the process of binding Cr2O7 2− on HSA was a spontaneous molecular interaction procedure. Ionic, H-bonds and van der Waals interactions play a major role in stabilizing the complex. The Cr2O7 2− altered the environments of Trp and Tyr residues in HSA. [Copyright &y& Elsevier]

The interactions of 2, 4-dinitrophenol and 2, 4-dichlorphenol with trypsin were investigated by fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectra techniques under physiological pH 7.40. The 2, 4-dinitrophenol and 2, 4-dichlorphenol effectively quenched the intrinsic fluorescence of trypsin via static quenching. The process of binding 2, 4-dinitrophenol and 2, 4-dichlorphenol with trypsin was a spontaneous molecular interaction procedure. The electrostatic repulsion does favor the interaction between 2, 4-DNP and trypsin. However, the interaction of 2, 4-DCP and trypsin can be explained on the basis of hydrogen bonding and van der Waals. The results of synchronous fluorescence spectroscopy and three-dimensional fluorescence spectra indicated that the structure of these trytophan and tyrosine residues environments were altered by 2, 4-DNP and 2, 4-DCP. [ABSTRACT FROM AUTHOR]

Abstract: A new fluoride borate crystal, CdZn2KB2O6F, has been synthesized by flux-supported solid-state reaction. The crystal structure has been determined by single-crystal X-ray diffraction. It crystallizes in the trigonal space group with a=5.0381(6)Å, b=5.0381(6)Å, c=15.1550(19)Å, α=90.00°, β=90.00°, γ=120.00°, Z=2. The crystal represents a new structure type in which ZnBO3 layers are connected through bridging fluorine and cadmium atoms alternately along the c-axis. K+ cations are filled in the intralayer open channels to balance charge. IR and Raman spectra further confirm the crystal structure. Photoluminescent measurement reveals that CdZn2KB2O6F exhibits blue fluorescence at room temperature in the solid-state. [Copyright &y& Elsevier]

Objectives: To investigate the role of TNFAIP3 deletions and NF-κB activation in extranodal natural killer/T-cell lymphoma (ENKTCL), nasal type.Methods: In total, 138 patients with ENKTCL were included. Activation of NF-κB pathway and expression of TNFAIP3 (A20) were examined by immunohistochemistry. TNFAIP3 was analyzed for deletions using FICTION (fluorescence immunophenotyping and interphase cytogenetics as a tool for investigating neoplasms), for mutations using Sanger sequencing, and for promoter methylation using methylation-specific sequencing.Results: NF-κB pathway activation was observed in 31.2% of cases (43/138), TNFAIP3 expression was negative in 15.2% of cases (21/138), and heterozygous TNFAIP3 deletion was observed in 35% of cases (35/100). TNFAIP3 exons 2 to 9 mutations and promoter methylation were not observed. Kaplan-Meier analysis showed patients with NF-κB pathway activation or TNFAIP3 heterozygous deletion to have a longer overall survival.Conclusions: Our study demonstrated that NF-κB activation and TNFAIP3 heterozygous deletion confer superior survival in patients with ENKTCL. [ABSTRACT FROM AUTHOR]

A novel organic gelator (WJ) based on benzimidazole and acylhydrazone naphthol moities has been designed and synthesized. The organic gelator (WJ) could form a stable organogel (WJG) with strong aggregation-induced emission (AIE). Interestingly, the WJG shows multi-stimuli-response for many analytes such as CN−, Al3+ and Fe3+ and l-Cys. Therefore, a multi-analyte sensor array based on WJG has been successfully developed. The WJG presents selective fluorescent and colorimetric response for CN−. Meanwhile, the WJG could selectively identify Fe3+ and Al3+ in the gel state. With the addition of Fe3+ the yellow-green AIE of WJG was quenched. In addition, the AIE of WJG could be selectively recovered by adding l-Cys. So the AIE presents an “on–off–on” type by alternatively adding Fe3+ and l-Cys. Moreover, upon the addition of Al3+, the yellow-green AIE of WJG shows a blue shift and changes to blue. The detection limits of the sensor array for CN−, Al3+ and Fe3+ are 3.02 × 10−6 M, 5.78 × 10−8 M, and 3.81 × 10−9 M, respectively. The WJG could act as a multi-analyte detection and fluorescent display material. [ABSTRACT FROM AUTHOR]

In this study, a new fluorescent probe (LR1) for lysosomal HOCl was developed by integrating a morpholine moiety, a lysosome-targeting group, into the rhodamine framework. LR1 exhibited remarkable fluorescence intensity enhancement at 582 nm upon HOCl titration with a low detection limit (2.6 nM), which indicated that the probe may be capable of monitoring HOCl fluctuations at trace levels. Moreover, the probe was applied in cellular fluorescence imaging, and the results demonstrated that it could sense endogenous HOCl with low cytotoxicity in RAW264.7 cells. In addition, LR1 was found to be capable of monitoring HOCl changes in lysosomes owing to the introduction of morpholine, which served as a lysosome-targeting group. We expect that the probe has great potential as a practical molecular tool for exploring HOCl-related biology in lysosomes. [ABSTRACT FROM AUTHOR]

A novel pyrazoline with benzimidazole substituent was conveniently synthesized, starting from a chalcone and 2-hydrazinylpyridine. The addition of Ni 2+ to ethanol solution of the synthesized pyrazoline resulted in a rapid color change from blue to green which allows the selective detection of Ni 2+ ion over a great number of other metal ions. The association constant for the 1:1 complex was determined to be 2.72 × 10 7 M −1 . [ABSTRACT FROM AUTHOR]

One symmetrical and two unsymmetrical dimesitylboryl-substituted BTD derivatives 1-3 were prepared through Pd(0)-catalyzed Suzuki coupling reaction. All these compounds display intense fluorescence not only in solution but also in the solid state due to steric bulkiness of the boryl group, which is effective to suppress the intermolecular interactions in the solid state. In addition, the boryl-substituted BTD 1 displays prompt fluorescence responses to fluoride ions with high sensitivity through the complexation of the boron center with fluoride, demonstrating its potential utility as fluorescent sensor for fluoride ions. [ABSTRACT FROM AUTHOR]

Abstract: A series of novel 5-aryl-3-benzimidazolyl-1-phenyl-pyrazoline derivatives were synthesized by the reaction of benzimidazolyl chalcone and phenylhydrazine in 41–72% yields. The compounds were characterized using IR, 1H NMR and HRMS. Absorption and fluorescence spectra were measured in different organic solvent. An intense absorption maxima was noted at ca. 370nm and emission maxima was noted at ca. 460nm. The absorption spectra of the pyrazoline derivatives reveal that 5-aryl group attached to the pyrazoline ring hardly influenced the maximum absorption. The fluorescence spectra of these compounds indicated the emission wavelength was red shifted and the fluorescence intensity was decreased with the increase in solvent polarity. [Copyright &y& Elsevier]

Abstract: The binding interactions of lysozyme with 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol were investigated by UV–vis absorption, CD, fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectra techniques under physiological pH 7.40. The binding constants, quenching mechanism, and the number of binding sites were determined by the quenching of lysozyme fluorescence in presence of chlorophenols. H-bonds and hydrophobic interactions played major roles in stabilizing the chlorophenols–lysozyme complex. The distances r between chlorophenols and lysozyme were calculated to be 1.94nm, 2.75nm, 3.54nm, and 3.76nm for 2-CP, 2,4-DCP, 2,4,6-TCP, and PCP, respectively. The effects of chlorophenols on the conformation of lysozyme were analyzed using CD, synchronous fluorescence and three-dimensional fluorescence spectra. [Copyright &y& Elsevier]

Abstract: Five novel complexes, Co(OBt)2 ·7H2O (1) (OBt=1-hydroxybenzotriazole ion), Ni3(OBt)6 ·6H2O (2), [Ag(OBt)(HOBt)] n (3), [Zn(OBt)2] n (4) and [Cu2(OBt)4 ·3H2O] n (5) were synthesized by hydrothermal method and characterized by elemental analysis, IR spectroscopy, TGA, XRPD, and single-crystal X-ray diffraction. The results from single-crystal X-ray diffraction indicate that 1–5 are zero-dimensional (0D), zero-dimensional, one-dimensional (1D), and three-dimensional (3D) frameworks, respectively. In particular, 3 is twin crystal; 4 possesses of double-stranded chains; 5 crystallizes in orthorhombic space group P212121 with a helical chain in its structure. The luminescence properties and the magnetic properties of the five complexes were investigated. [Copyright &y& Elsevier]

The charge neutral anthracene based chiral fluorescent receptors 4a and 4b containing thiourea and amide groups were synthesized by simple steps in good yields, and their enantioselective recognition for chiral dicarboxylic anions (L/D-malate, L/D-aspartate, and L/D-glutamate) were examined by UV–vis, fluorescence, and 1H NMR spectroscopy. The sensor 4a exhibited an excellent enantioselective recognition ability towards malate (Kass (L)/Kass (D) = 9.65).Key words: enantioselective recognition, chiral chemosensor, fluorescence, malate. Faisant appel à une méthode n’impliquant que des étapes simples, on a effectué avec de bons rendements la synthèse des récepteurs fluorescents chiraux liés à des anthracènes électriquement neutres, 4a et 4b, qui contiennent des groupes amide et thiourée; faisant appel à la spectroscopie UV-visible, à la spectroscopie de fluorescence et à la spectroscopie RMN du 1H, on a aussi évalué leur habilité à reconnaître d’une façon énantiosélective les anions dicarboxyliques chiraux (L/D-malate; L/D-aspartate et L/D-glutamate). Le senseur 4a possède une excellente habilité à reconnaître d’une façon énantiosélective le malate (Kass (L)/Kass (D) = 9,65).Mots-clés : reconnaissance énantiosélective, senseur chimique chiral, fluorescence, malate.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Abstract: Rare earth complexes/silver nanoparticles nanocomposite was prepared by introducing Tb(TTA)3Bipy as stabilizer. The radiative properties of the nanocomposite were studied by experiments and spectra calculation. The transmission electron microscope image of the composite indicates that the silver nanoparticles are spherical, monodispersed and with an average size of 18nm. Fluorescence study shows silver nanoparticles have both enhancement effect and quenching effect on the fluorescence of europium complex, the total effect in such a composite system is an enhancement effect. Theory calculation prognosticates that the newly synthesized rare earth complexes/silver nanoparticles nanocomposite could be used in polymer optical fiber amplifier and laser materials. [Copyright &y& Elsevier]

Abstract: Effects of synergetic ligands of the europium complexes Eu(TTA)3nL (Eu denotes the central ion Eu(III), TTA denotes the β-diketone ligand α-thenoyltrifluoroacetone, L denotes the synergetic ligands triophenylphosphine oxide, 1,10-phenanthroline, 2,2′-bipy and H2O, respectively) on fluorescence properties and supermolecular structures of Langmuir and Langmuir–Blodgett films were studied. Experiments on the Langmuir trough showed that different supermolecular structures were formed for each complex with different synergetic ligands, in which aggregate structure was found at the air/subphase interface for Eu(TTA)3Phen and multilayer structure for the other three complexes. This result is accordance with the R values calculated in terms of their fluorescence spectra. Fluorescence enhancement was found to be in an order of the relative emission intensity of the fluorescent LB films: I(Eu(TTA)3(TPPO)2)> I(Eu(TTA)3Phen)> I(Eu(TTA)3Bipy)> I(Eu(TTA)3·2H2O). Detailed analysis on the LB film containing Eu(TTA)3(TPPO)2 revealed that the LB film containing Eu(TTA)3(TPPO)2 not only have the strongest red light emit, the best monochromacity, good miscibility with arachidic acid (AA), but also have condensed structure, controllable nanometer-scale thickness and vertical uniformity. [Copyright &y& Elsevier]

A novel tandem reaction of 5-carbonylpyrazole derivatives with 4-bromobut-2-enenitrile provides access to pyrazolopyridine derivatives displaying blue fluorescence. [ABSTRACT FROM AUTHOR]