A novel resorufin based fluorescent “turn-on” probe for the selective detection of hydrazine and application in living cells

In this study, a resorufin derivative RTP-1, which is a novel fluorescent ‘‘turn-on' probe for sensitive detection of hydrazine within 30 min, is designed and synthesized. The selective deprotection of the ester group of the probe by hydrazine led to a prominent enhancement of fluorescent intensity, as well as a remarkable color change from colorless to pink, which could be distinguished by naked eye. The fluorescence enhancement showed decent linear relationship with hydrazine concentration ranging from 0 to 50 mmol/L, with a detection limit of 0.84 mmol/L. The specificity of RTP-1 for hydrazine to a number of metal ions, anions and amines is satisfactory. The sensing mechanism of RTP-1 and hydrazine was evaluated by HPLC, ESI mass spectrometry and density functional theory(DFT).Moreover, we have utilized this fluorescent probe for imaging hydrazine in living cells, and the fluorescence was clearly observed when the cells were incubated with hydrazine(100 mmol/L) for 30 min.     

A highly sensitive “turn-on” fluorescent probe for bovine serum albumin protein detection and quantification based on AIE-active distyrylanthracene derivative

A sulfonated 9,10-distyrylanthracene derivative with aggregation-induced emission (AIE) property is designed and synthesized. It shows a highly sensitive and selective fluorescence enhancement property for bovine serum albumin (BSA) protein detection and quantification. Analysis on the interaction between the probe molecule and BSA reveals the essential role of the hydrophobic cavities of the protein folding structure.     

A highly selective colorimetric and “Off-On” fluorescence sensor for CN~- based on Zn(salphenazine) complex

The development of sensors for selective detection of cyanide ion(CN~-) is an important mission to accomplish because of the versatility and toxicity of CN~-. In the present work, an "ensemble"-based colorimetric and fluorescent sensor(L2-Zn~(2+)) for CN~-ion has been developed. The addition of cyanide ions removed Zn~(2+) from the ensemble(L2-Zn~(2+)) in aqueous medium, resulting in a color change of the solution from red to buff and a "turn-on" fluorescent response. Also, the sensitivity of both the fluorescenceand colorimetric-based assay is below the maximum allowable level of cyanide ions in drinking water set by the World Health Organization. In addition, test strips, which served as convenient and efficient CN~- test kits, were fabricated based on the sensor.Notably, the selective detection of cyanide with L2-Zn~(2+) for practical application was also performed in sprouting potatoes.     

A new BODIPY-based fluorescent “turn-on” probe for highly selective and rapid detection of mercury ions

A new fluorescent sensor based on the BODIPY fluorophore and the carboxyl-thiol metal bonding receptor for Hg²⁺ was designed and synthesized. The sensor is highly selective for Hg²⁺ (about 630-fold fluorescence enhancement) over relevant competing metal ions, sensitive to ppb levels of Hg²⁺ (with detection limit of 5.7?nM), and fast response toward Hg²⁺ (within 30?s) in aqueous solution.     

An oxidative cyclization reaction based fluorescent “Turn-On” probe for highly selective and rapid detection of hypochlorous acid

A novel fluorescent turn-on probe, PHC1, for the detection of hypochlorous acid has been developed based on hypochlorous acid-initiated oxidative intramolecular cyclization. Endowed by the fast reaction rate, PHC1 features rapid detection kinetics, as well as high degree of selectivity and sensitivity for HClO.     

A highly selective and sensitive fluorescent chemosensor for Zn^2＋

A new selective Zn^2＋ fluorescent chemosensor, o-vanillin-4-ethoxybenzoylhydrazone （1）, was designed and prepared. Free 1 mainly displayed very weak fluorescence at 480 nm upon excitation at 403 nm. It displayed high selectivity for Zn^2＋ and had a 518- fold fluorescent enhancement upon binding of Zn^2＋, while the other cation ions had only little influence on the fluorescence of 1. Mechanism of enhancement of l＇s fluorescence by Zn^2＋ was briefly discussed.     

A highly selective turn-on colorimetric and luminescence sensor based on a triphenylamine-appended ruthenium(Ⅱ) dye for detecting mercury ion

A dual colorimetric and luminescent sensor based on a heteroleptic ruthenium dye[Ru(Hipdpa)(Hdcbpy)(NCS)_2]~-·0.5H~+ 0.5[N(C_4H_9)_4]~+ Ru(Hipdpa) {where Hdcbpy = monodeprotonted-4,4'-dicarboxy-2.2'-bipyridineand Hipdpa = 4-(1H-imidazo[4,5-f][l,10]phenanthroIin-2-yl)-N,N-diphenylaniIine} for selective detection of Hg~(2+) is presented.The results of spectrophotometric titrations revealed an evident luminescence intensity enhancement(I/I_0 =11) and a considerable blue shift in visible absorption and luminescence maxima with the addition of Hg~(2+).The sensitive response of the optical sensor on Hg~(2+) was attributed to the binding of the electron-deficient Hg~(2+) to the electron-rich sulfur atom of the thiocyanate(NCS) ligand in the Ru(Hipdpa).which led to an increase in the energy gap between the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO).Accordingly,the blue shift in the absorption spectrum of Ru(Hipdpa) due to the binding of Hg~(2+) was obtained.Ru(Hipdpa) was found to have decreased Hg~(2+) detection limit and improved linear region as compared to di(tetrabutylammonium) ris-bis(isothiocyanato)bis(2,2'-bipyridine-4-carboxylic acid-4'-carboxylate)ruthenium(Ⅱ) N719.Moreover,a dramatic color change from pink to yellow was observed,which allowed simple monitoring of Hg~(2+) by either naked eyes or a simple colorimetric reader.Therefore,the proposed sensor can provide potential applications for Hg~(2+) detection.     

A theoretical study on magnesium ion–selective two-photon fluorescent probe based on benzo [h] chromene derivatives

The geometrical structure, electronic structure, and one-photon absorption (OPA) properties of a series of magnesium ion (Mg²⁺)-selective fluorescent probes based on benzo [h] chromene derivatives have been theoretically studied by using density functional theory (DFT) method and Zerner’s intermediate neglect of differential overlap (ZINDO) methods. Their two-photon absorption (TPA) properties are also calculated by using the method of ZINDO/sum-over-states. Results show that all studied probe molecules exhibit large TPA cross-section (δ_max) in response to Mg²⁺ in 700- to 1,200-nm range. Furthermore, the δ_max can be greatly enhanced by introducing acceptor groups to the lateral side of benzo [h] chromene. And that probes with stronger acceptor group show larger δ_max and result in 70-fold enhancing when coordinate with Mg²⁺. Significantly, probe molecules with good cell permeability were also studied by replacing the hydrogen group with acetoxymethyl ester, but δ_max changed slightly. These results shed light into the design strategy of efficient TP fluorescent probes with large δ_max and good cell permeability for Mg²⁺ sensing in living systems.     

A fluorescent Eu(Ⅲ) MOF for highly selective and sensitive sensing of picric acid

A metal-organic framework [Eu_3L_3(CH_3COO)_2(H_2O)_2(μ_3-OH)]·3 DMF,(EuL, H_2L=9H-carbazole-2,7-dicarboxylic acid,DMF=N,N-dimethylformamide) has been synthesized under solvothermal conditions and structurally characterized. In EuL,Eu_6O_8 clusters are four-bridged by carboxylates to form parallel-aligned Eu–O–C chains, which are further linked by the carbazole moieties of L~(2-) ligands to form the three-dimensional framework with rhombic channels. The EuL material with characteristic emission of Eu~(3+) ion exhibits significant luminescence quenching response for picric acid(PA) and the linear Stern-Volmer plot was observed in the concentration range of 0.05–0.15 mM with K_(sv) of 98074 M~(-1). As far as we know, this Ksv is among the highest values for COFs and MOFs in detection of PA. The excellent anti-interference ability and repeatability were also verified by experiments. Lastly, we investigated the luminescence quenching mechanism in the EuL sensing system.     

A highly sensitive ＂turn-on＂ fluorescent probe for bovine serum albumin protein detection and quantification based on AIE-active distyrylanthracene derivative

A sulfonated 9,10-distyrylanthracene derivative with aggregation-induced emission （AIE） property is designed and synthesized. It shows a highly sensitive and selective fluorescence enhancement property for bovine serum albumin （BSA） protein detection and quantification. Analysis on the interaction between the probe molecule and BSA reveals the essential role of the hydrophobic cavities of the protein folding structure.     

1-Pyrenecarboxaldehyde thiosemicarbazone:A novel fluorescent molecular sensor towards mercury(Ⅱ) ion

<正>A novel and simple fluorescent molecular sensor,1-pyrenecarboxaldehyde thiosemicarbazone(Hpytsc),was synthesized.Its higher sensitivity and selectivity to mercury(Ⅱ) ion were studied through absorption and emission channels.The UV-vis spectra show that the increasing mercury(Ⅱ) ion concentrations result in the decreasing absorption intensity.The fluorescence monomer emission of Hpytsc is enhanced upon binding mercury(Ⅱ) ion,which should be due to the 1:1 complex formation between Hpytsc and metal ion.     

A series of novel Zn(Ⅱ) and Mn(Ⅱ) metal-organic frameworks constructed by 2,4-bis-oxyacetate-benzoic acid: syntheses,structures and photoluminescence

A new carboxylic acid ligand, 2,4-bis-oxyacetate-benzoic acid(H3BOABA), was designed and introduced to construct novel metal-organic framework materials. [Zn Na(BOABA)(phen)(H2O)]·H2O(1), Zn Na(BOABA)(2), Mn3(BOABA)2(phen)2(3), [Mn2(BOABA)(OH)]·(H2O)2(4)(CCDC: 885138, 885137, 894225, 883094) were hydrothermally synthesized and characterized by elemental analysis, IR spectra and thermal gravimetric analyses. Crystal structures of the complexes were determined by single crystal X-ray diffraction method. Complex 1 is a one dimensional double edges non-interpenetrated framework decorated by the phen ligands on the surface. Complex 2 is an unique three dimensional open framework, consisting of Zn(II) and Na(I). Complex 3 is an unique double edges one dimensional MOF containing a [Mn3(BOABA)2(phen)2]n non-interpenetrated structure. Complex 4 is a two dimensional plane structure containing two Mn atoms in the same coordination environment. The interaction between four complexes and DNA were studied by Et Br fluorescence probe. Meanwhile, photoluminescence studies revealed that these four complexes display strong fluorescent emission bands in the solid state at room temperature.     

Trinuclear Cu(Ⅱ) and Zn(Ⅱ) complexes bridged by μ_3-carbonato anion

The trinuclear Cu(Ⅱ) and Zn(Ⅱ) complexes [(CuTPA)_3(μ3-CO_3)] (ClO_4)_4(1) and [(ZnTPA)_3(μ_3-CO_3)] (ClO_4)_4 (2) (TPA=tri(pyridylmethyl) amine) have been synthesized. X-ray structure analysis of the two complexes proves that CO_3~(2-) anion has an unusual triply bridging ligand, bridging three CuTPA and ZnTPA units respectively, and assembles new trinuclear complexes. The CO_3_(2-) comes from atmospheric CO_2. The structure of each trinuclear unit consists of three copper or zinc atoms in a five-coordinate triangular bipyramidal environment. The [(CuTPA)_3 (μ_3-CO_3)] (ClO_4)_4 compound shows a very weak antiferromagnetic coupling.     

A carbazole-hemicyanine dye based ratiometric fluorescent probe for selective detection of bisulfite (HSO3−) in cells and C. elegans

A colorimetric and ratiometric fluorescent probe for selective detection of HSO₃^- based on the 1,4-nucleophilic addition reaction was successfully synthesized and applied to the detection of exogenous HSO₃^- in Hela cells and C. elegans.     

Ratiometric and selective two-photon fluorescent probe based on PET-ICT for imaging Zn2+in living cells and tissues简

A two-photon fluorescent probe TPZn was developed for specific ratiometric imaging Zn2＋ in living cells and tissues. Significant ratiometric fluorescence change was based on photoinduced electron transfer and intramolecular charge transfer. The synthetic method of TPZn was simple. It was successfully used to selectively image Zn2＋ based on the higher binding affinity for Zn2＋ than for Cd2＋. TPZn was easily loaded into the living cell and tissues with high membrane permeability in a complex biological environment. TPZn could clearly visualize endogenous Zn2＋ by TP ratiometric imaging in hippocampal slices at a depth of 120 μm. Thus, TPZn is a useful tool to image of Zn2＋ in living cells and tissues without interference from Cd2＋.     

A reversible fluorescent INHIBIT logic gate for determination of silver and iodide based on the use of graphene oxide and a silver–selective probe DNA

We describe a reversible fluorescent DNA–based INHIBIT logic gate for the determination of silver(I) and iodide ions using graphene oxide (GO) as a signal transducer and Ag(I) and iodide as mechanical activators. The basic performance, optimized conditions, sensitivity and selectivity of the logic gate were investigated and revealed that the method is highly sensitive and selective over potentially interfering ions. The limits of detection for Ag(I) and iodide are 10 nM and 50 nM, respectively. This logic gate was successfully applied to the determination of Ag(I) and iodide in (spiked) tap water and river water. It was also used for the determination of iodide in human urine samples with satisfactory results. Compared to other methods, this INHIBIT logic gate is simple in design and has small background interference.

A simple and reversible fluorescent DNA-based INHIBIT logic gate is designed by using graphene oxide as a signal transducer and silver ions and iodide as mechanical activators.

     

A highly selective fluorescent sensor for fluoride anion based on pyrazole derivative: Naked eye “no–yes” detection

A new pyrazole-based fluorescent sensor, 5-amino-3-(5-phenyl-1H-pyrrol-2-yl)-1H-pyrazole-4-carboxamide (compound 1), was studied for fluoride anion (F^?) detection in organic or water-containing solution. This compound displayed both changes in UV–vis absorption and fluorescence emission spectra upon addition of F^?. With increasing of F^?, blue emission intensity increases drastically and reaches saturation with 607-fold enhancement at 424 nm. The results indicate that compound 1 has highly selectivity for fluoride detection over other anions, such as Cl^?, Br^?, I^?, HSO₄^?, H₂PO₄^? and AcO^? in DMSO or aqueous DMSO solutions. ¹H NMR titration and other experiments confirm that the sensing process is mainly from the deprotonation of the pyrazole–NH in compound 1.     

A highly sensitive and selective sensing ECL platform for naringin based on β-Cyclodextrin functionalized carbon nanohorns

A new electrochemiluminescent sensing platform utilizing β-Cyclodextrin functionalized carbon nanohorns as an electrochemiluminescent amplification and sensing element was developed for sensitive detection of naringin with good specificity and excellent stability.     

Synthesis and Crystal Structure of Zn(Ⅱ) Complex with Tridentate Ligand N-(2-Hydroxy-1-naphthylidene)-L-serine

A new Zn(Ⅱ) complex, [Zn(L)2(H2O)2], where H2L = N-(2-hydroxy-l-naphthylidene)-L-serine, has been synthesized and characterized by single-crystal X-ray diffraction. The crystal belongs to monoclinic system, space group C2/c with a = 13.669(2), b = 6.4657(9), c =31.463(5) (A), β = 98.010(2)°, V = 2753.6(7) (A)3, Z = 8, Mr = 358.64, Dc = 1.730 g/cm3, F(000) =1472,μ(MoKa) = 1.814 mm-1, the final R = 0.0355 and wR = 0.0706. The Zn(Ⅱ) atom adopts a square-pyramidal geometry coordinated by the tridentate ligand and two water molecules.Intermolecular hydrogen bonds link the complex molecules into a two-dimensional layer.