A red-emissive benzothiazole-based luminophore with ESIPT and AIE natures and its application for detecting and imaging hypochlorous acid.

A new "ESIPT + AIE" based dye of benzothiazole with red emission and a large Stokes shift was constructed by combining 2-(2'-hydroxyphenyl)benzothiazole as the ESIPT unit and α-cyanostilbene as the AIE unit. The compound BACN was found to be a ideal HClO chemosensor, and presented palpable fluorescence and colorimetric responses toward HClO via the HClO-trigged oxidation cleavage of the ethylene bridge activated by the electron withdrawing cyano group. BACN was capable of recognizing HClO rapidly (12 s) and sensitively under physiological conditions, with good selectivity over other biologically pertinent substances. Thanks to strong red emission (λem = 606 nm) and large Stokes shift (213 nm) resulted from the combination of ESIPT and AIE effects, it was successfully utilized for the recognition of exogenous and endogenous HClO in living HeLa cells.

An N-nitrosation reaction-based fluorescent probe for detecting nitric oxide in living cells and inflammatory zebrafish.

Nitric oxide (NO), an essential biological messenger molecule, participates in various physiological and pathological processes. The sensitive and specific detection of NO is of great significance for understanding the biological function of NO. Here, we synthesized a fluorescent probe (Rho-NO) for highly selective detection of NO both in vitro and in vivo. The high selectivity of Rho-NO is attributed to the fact that NO is easily replaced by electron donor amino group to form N-nitrosation products, causing rhodamine spiro ring open and fluorescence emit. Rho-NO showed a good linear response to NO (0-100 µM) with a low detection limit (0.06 µM). Importantly, it exhibited excellent specificity for NO detection in human serum and was also applied for imaging NO in living cells and inflammatory model of zebrafish. This work proves the potential of Rho-NO in pathological research and disease diagnosis.

Fluorescent porous organic cage with good water solubility for ratiometric sensing of gold(III) ion in aqueous solution.

Fluorescent porous organic cage with good water solubility is of great interest but still challenging for its fluorescent sensing application. Poor water solubility and single signal of most previous probes are unfavorable for the monitoring of Au3+ generated from the potential dissociation of gold nanoparticles in environmental and biological samples. Here we report a water-soluble porous organic cage as a ratiometric fluorescent probe for Au3+ in aqueous solution. The prepared porous organic cage with good water solubility showed specific redox interaction with Au3+ in pH 5, leading to the change of dual emission at 420 and 484 nm. Based on the change of fluorescence ratio, a simple ratiometric sensing method for Au3+ from the dissociation of gold nanoparticles in aqueous solution was developed. The proposed method gave a calibration function of F484/F420 = 0.0370[Au3+] + 0.5689 (where F484/F420 is the intensity ratio of fluorescence at 484 nm to that at 420 nm; [Au3+] in µM) (R2 = 0.9975) in the concentration range of 1-60 µM, the limit of detection (3s) of 8 nM, and the relative standard deviation of 0.26% for 10 replicate detections of 50 µM Au3+. The recoveries of spiked Au3+ in domestic wastewater and human serum samples ranged from 94.66% to 105.61%.

A morpholino hydrazone-based lysosome-targeting fluorescent probe with fast response and high sensitivity for imaging peroxynitrite in living cells.

Peroxynitrite (ONOO-) plays important roles in many pathophysiological processes and its subcellular detection draws increasing attention. In this study, we designed and prepared a novel lysosome-targetable fluorescent probe (E)-2-(benzo[d]thiazol-2- yl)-4-methyl-6-((morpholinoimino)methyl)phenol (BMP) for selective detection of ONOO- in living systems by incorporating a reactive morpholino hydrazone as new ONOO- response site into a benzothiazole derivative as fluorophore. After reaction with ONOO-, an obvious fluorescence increase (83-fold) was observed accompanied with distinct dual colorimetric and fluorescence changes. Probe BMP displayed the merits of fast response (<3 s), ultrasensitivity (LOD = 6 nM) and high selectivity towards ONOO- over other physiological species including ROS/RNS. Most importantly, the probe was capable of imaging ONOO- in lysosomes of living cells with good cell permeation and negligible cytotoxicity. Therefore, this research provides an effective tool to study the functions of ONOO- in lysosomes.

Modification of mesoporous silica with molecular imprinting technology: A facile strategy for achieving rapid and specific adsorption.

In order to improve the diffusion kinetics of molecularly imprinted materials (MIMs), applying imprinting technology to mesoporous materials is a promising strategy. In the present study, an imprinting approach based on the combination of mesoporous silica materials and molecular imprinting technology is reported. Molecularly imprinted material (MIM) for 2,4-dichlorophenoxyacetic acid (2,4-D) was prepared by using 2,4-D as the template molecule, alkyne-modified ß-cyclodextrin and propargyl amine as the combinatorial functional monomers and SBA-15 as the supporter. The functional monomers were anchored to the azide-modified SBA-15 by azide-alkyne Click reaction. The synthesized MIM was characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), thermal gravimetric analysis (TGA), low-angle X-ray diffraction (XRD) and N2 adsorption-desorption analysis. The interactions between template and functional monomers were studied by proton NMR analysis and UV-vis experiments. The results of the equilibrium binding experiments and selective tests showed that the prepared MIM has binding affinity and specificity for a group of analytes which have similar size and shape to those of template. Binding kinetic experiments demonstrated that the present imprinting approach can effectively enhance the mass transfer rate. The solid phase extraction of 2,4-D using MIM as the adsorbent was investigated. The extraction conditions for the processes of loading, washing and eluting were optimized. The recoveries of the molecularly imprinted solid phase extraction (MISPE) column for 2,4-D were 76.3-88.9% with relative standard deviations (RSD) of 3.48-7.64%.

Ag/N-doped reduced graphene oxide incorporated with molecularly imprinted polymer: An advanced electrochemical sensing platform for salbutamol determination.

In this work, the metallic silver and non-metallic nitrogen co-doped reduced graphene oxide (Ag-N-RGO) was first synthesized by a simple and cost-effective strategy, and then a molecularly imprinted polymer (MIP) was formed in situ at the surface of the prepared composite via electropolymerization of o-phenylenediamine in the presence of salbutamol as the template molecule. The electrochemical characterizations demonstrate that the bifunctional graphene-based composite shows improved catalytic performance than that of pristine graphene doped with one-component or none. The MIP sensor based on Ag-N-RGO owns high porous surface structure, resulting in the increased current response and enhanced recognition capacity than that of non-imprinted sensor. The outstanding performance of the developed sensor derives from the combined advantages of Ag-N-RGO with effective catalytic property and MIP with excellent selectivity. Under the optimal conditions, the electrochemical response of the developed sensor is linearly proportional to the concentration of salbutamol in the range of 0.03-20.00µmolL-1 with a low detection limit of 7 nmol L-1. The designed sensor has exhibited the multiple advantages such as low cost, simple manufacture, convenient use, excellent selectivity and good reproducibility. Finally, the proposed method has been extended for the determinations of salbutamol in human urine and pork samples, and the satisfactory recoveries between 98.9-105.3% are achieved.

Fluorescent molecularly imprinted polymers based on 1,8-naphthalimide derivatives for efficiently recognition of cholic acid.

Fluorescent molecularly imprinted polymers (MIPs) have attracted increasing attentions in recent years due to their high selectivity and sensitivity for target molecules. In this study, two cholic acid imprinted fluorescent polymers, i.e., MIP1 and MIP2, were prepared using 4-dimethylamino-N-allylnaphthalimide (F1) and 4-piperazinyl-N-allylnaphthalimide (F2) as the fluorescent functional monomers, respectively. The fluorescence intensity of MIP1 decreased linearly with the increase of the template concentration in the range of 1.50-120.0 µM, while the fluorescence intensity of MIP2 increased linearly with the increase of the template concentration in the range of 0.40-110.0 µM. The detection limits of MIP1 and MIP2 for cholic acid were 0.42 and 0.083 µM, respectively. The mechanisms of the fluorescence responsive of the imprinted polymers were discussed. The results of fluorescence measurement and binding experiments demonstrated that both imprinted polymers have high recognition abilities and binding affinities for the template. The imprinted polymers have been successfully applied to the determination of cholic acid in human serums. The present study indicated that 1,8-naphthalimide can be used as a modular building block for design and construction of various fluorogenic molecularly imprinted materials for practical sensing and separation.

Fluorescent boronic acid terminated polymer grafted silica particles synthesized via click chemistry for affinity separation of saccharides.

Boronic acids are important for effective separation of biological active cis-diols. For the purpose of constructing a new type of saccharide-sensitive material which can not only provide convenient separation but also improve the access of boronic acid to guest molecules, the fluorogenic boronic acid terminated, thermo-sensitive polymers (BA-polyNIPAm) were grafted to an alkyne modified silica gel through the exploitation of click chemistry. The BA-polyNIPAm grafted silica gel (BA-polyNIPAm-SG) was characterized by FT-IR, fluorescence spectra, fluorescence microscopy, elemental analysis (EA), thermal gravimetric analysis (TGA), scanning electron microscope (SEM) and so on. BA-polyNIPAm-SG displayed affinity binding ability for saccharides under physiological pH value and allowed saccharides to be conveniently separated from solution. The maximum binding capacities for fructose and glucose are 83.2 µmol/g and 70.4 µmol/g polymer, respectively. The intensity of fluorescence emission of BA-polyNIPAm-SG increased with the increasing of fructose concentration. The present study provides a new kind of composite material which contains moveable and flexible grippers for recognizing and binding guest molecules.

Preparation of 2D molecularly imprinted materials based on mesoporous silicas via click reaction.

The two-dimensional (2D) molecular imprinting approach has attracted extensive research interest in recent years due to its potential advantages such as simple construction, fast template removal and rapid mass transfer. In this study, a new 2D imprinting approach based on the combination of mesoporous silica materials and molecular imprinting technology is reported. 2D molecularly imprinted materials (MIMs) for cholesterol were prepared by using cholesterol as the template, azide modified ß-cyclodextrin (azide-ß-CD) as the functional monomer and alkynyl-modified SBA-15 (alkyne-SBA-15) as the skeleton. In this method, azide-ß-CD molecules were first assembled around the templates by formation of template-monomer complexes, and thus the mutual positions of azide-ß-CD molecules were fixed. Then, azide-ß-CD molecules were anchored to the walls of the nano-pores of SBA-15 via click chemistry. After removal of the template molecules, the resulting cavities, i.e., recognition sites were formed in the nano-pores of mesoporous silicas. The synthesized MIM was characterized by FT-IR, X-ray diffraction (XRD), elemental analysis (EA), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM) and so on. Binding kinetic experiments demonstrated that the 2D imprinting approach can improve site accessibility for the template effectively. The 2D MIM exhibited binding affinity and specificity for the template, as revealed by equilibrium binding experiments. When using MIM as a stationary phase for HPLC, baseline separation of cholesterol from other compounds can be achieved. In addition, the use of 2D imprinting significantly reduced the peak broadening and tailing.

Fluorogenic molecularly imprinted polymers with double recognition abilities synthesized via click chemistry.

This paper reports a new strategy for the preparation of molecularly imprinted polymer (MIP) based composite materials with double recognition abilities through the exploitation of click chemistry. Combining the inherent molecular recognition ability of MIPs and the affinity binding ability of boronic acid ligands for saccharides, a boronic acid-attached MIP with double recognition abilities was prepared. An alkyne modified 2,4-dichlorophenoxyacetic acid (2,4-D) imprinted polymer was first synthesized using a two-stage precipitation polymerization. An azide-contained boronic acid was then linked to the clickable 2,4-D imprinted polymers through copper-catalyzed azide-alkyne cycloaddition (CuAAC). The boronic acid-attached MIPs displayed recognition ability for 2,4-D and affinity binding ability for saccharides at physiological pH. The intensity of fluorescence emission of the boronic acid-attached MIPs was found to increase when increasing amounts of a cis-diol compound (i.e., fructose) were added.

Dichlorido(4'-ferrocenyl-2,2':6',2''-terpyridine-κN,N',N'')zinc acetonitrile monosolvate.

The title complex, [FeZn(C(5)H(5))Cl(2)(C(20)H(14)N(3))]·CH(3)CN, is composed of one Zn(II) atom, one 4'-ferrocenyl-2,2':6',2''-terpyridine (fctpy) ligand, two Cl atoms and one acetonitrile solvent mol-ecule. The Zn(II) atom is five-coordinated in a trigonal-bipyramidal geometry by the tridentate chelating fctpy ligand and two Cl atoms.

Ester hydrolysis by a cyclodextrin dimer catalyst with a tridentate N,N',N''-zinc linking group.

A new beta-cyclodextrin dimer, 2,6-dimethylpyridine-bridged-bis(6-monoammonio-beta-cyclodextrin) (pyridyl BisCD, L), is synthesized. Its zinc complex (ZnL) is prepared, characterized, and applied as a catalyst for diester hydrolysis. The formation constant (log K(ML)=7.31+/-0.04) of the complex and deprotonation constant (pK(a1)=8.14+/-0.03, pK(a2)=9.24+/-0.01) of the coordinated water molecule were determined by a potentiometric pH titration at (25+/-0.1) degrees C, indicating a tridentate N,N',N''-zinc coordination. Hydrolysis kinetics of carboxylic acid esters were determined with bis(4-nitrophenyl)carbonate (BNPC) and 4-nitrophenyl acetate (NA) as the substrates. The resulting hydrolysis rate constants show that ZnL has a very high rate of catalysis for BNPC hydrolysis, yielding an 8.98x10(3)-fold rate enhancement over uncatalyzed hydrolysis at pH 7.00, compared to only a 71.76-fold rate enhancement for NA hydrolysis. Hydrolysis kinetics of phosphate esters catalyzed by ZnL are also investigated using bis(4-nitrophenyl)phosphate (BNPP) and disodium 4-nitrophenyl phosphate (NPP) as the substrates. The initial first-order rate constant of catalytic hydrolysis for BNPP was 1.29x10(-7) s(-1) at pH 8.5, 35 degrees C and 0.1 mM catalyst concentration, about 1600-fold acceleration over uncatalyzed hydrolysis. The pH dependence of the BNPP cleavage in aqueous buffer was shown as a sigmoidal curve with an inflection point around pH 8.25, which is nearly identical to the pK(a) value of the catalyst from the potentiometric titration. The k(BNPP) of BNPP hydrolysis promoted by ZnL is found to be 1.68x10(-3) M(-1) s(-1), higher than that of NPP, and comparatively higher than those promoted by its other tridentate N,N',N''-zinc analogues.

(4'-Ferrocenyl-2,2':6',2''-terpyridine-κN,N',N'')(1,10-phenanthroline-κN,N')copper(II) bis(perchlorate) acetonitrile solvate.

The title complex, [CuFe(C(5)H(5))(C(20)H(14)N(3))(C(12)H(8)N(2))](ClO(4))(2)·C(2)H(3)N, consists of a mononuclear [Cu(C(12)H(8)N(2))(C(25)H(19)FeN(3))](2+) cation, two ClO(4) (-) anions (one of which is disordered over two positions with equal occupancy) and one CH(3)CN solvent mol-ecule. The Cu(II) center has a distorted square-pyramidal coordination with three N atoms of the 4'-ferrocenyl-2,2':6',2''- terpyridine (fctpy) ligand and one 1,10-phenanthroline (phen) N atom in the basal plane and a second phen N atom in the apical position with an axial distance of 2.254 (4) Å. The disordered ClO(4) (-) anion is weakly coordin-ated to the Cu(II) ion with a Cu-O distance of 2.766 (11) Å. The two cyclo-penta-dienyl rings of the ferrocenyl group are almost eclipsed with a deviation of 4.7 (1) °, and are involved in inter-molecular π-π inter-actions with the outer pyridyl rings of the fctpy ligands [centroid-centroid distance = 3.759 (2) Å.].

(4'-Ferrocenyl-2,2':6',2''-terpyridine-κN,N,N)(1,10-phenanthroline-κN,N')zinc(II) bis-(perchlorate) acetonitrile monosolvate.

In the title complex, [FeZn(C(5)H(5))(C(20)H(14)N(3))(C(12)H(8)N(2))](ClO(4))(2)·CH(3)CN, the Zn(II) atom is five-coordinated by a tridentate chelating 4'-ferrocenyl-2,2':6',2''-terpyridine (fctpy) ligand and a bidentate chelating 1,10-phenanthroline (phen) ligand in a distorted square-pyramidal environment with a phen N atom located at the apical position [Zn-N = 2.259 (4) Å]. The terpyridyl motif in each fctpy ligand is coplanar, but the cyclo-penta-dienyl ring is twisted by 9.5 (2)° out of coplanarity with each central pyridine. The two cyclo-penta-dienyl rings of the ferrocenyl group are almost eclipsed with a deviation of 4.5 (1)°. In addition, inter-molecular π-π inter-actions [centroid-centroid distance 3.753 (2) Å] are present between the cyclo-penta-dienyl and outer pyridyl rings of the fctpy ligands. One of the perchlorate anions is equally disordered over two positions.

2,4,6-Tri-p-tolyl-pyridine.

In the title compound, C(26)H(23)N, the complete molecule is generated by crystallographic mirror symmetry, with the N atom and four C atoms lying on the reflection plane. The dihedral angles between the pyridine ring and pendant benzene rings are 2.9 (1), 14.1 (1) and 14.1 (1)°. Neighbouring mol-ecules are stabilized through inter-molecular π-π inter-actions along the c axis [centroid-to-centroid distance = 3.804 (2) Å], forming one-dimensional chains.

1-(2-Naphth-yl)-3-phenyl-prop-2-en-1-one.

The title compound, C(19)H(14)O, contains two independent mol-ecules with the same s-cis conformation for the ketone unit. Both mol-ecules are non-planar with dihedral angles of 51.9 (1) and 48.0 (1)° between the benzene ring and the naphthalene ring system. In the crystal, neighboring mol-ecules are stabilized by intermolecular C-H⋯π inter-actions, giving a two-dimensional supra-molecular array parallel to the ab plane.

Diaqua-bis(5-carb-oxy-2-methyl-1H-imidazole-4-carboxyl-ato-κN,O)cobalt(II) dimethyl-formamide disolvate.

In the title compound, [Co(C(6)H(5)N(2)O(4))(2)(H(2)O)(2)]·2C(3)H(7)NO, the Co(II) ion lies on an inversion center and adopts a slightly distorted CoN(2)O(4) octa-hedral geometry binding two bidentate chelating 5-carb-oxy-2-methyl-1H-imidazole-4-carboxyl-ate (H(2)MIDA(-)) monoanionic ligands and two axial aqua ligands. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link neighboring mol-ecules, generating a two-dimensional framework containing eight-membered H(4)O(4) rings. In addition, the dimethyl-formamide solvent mol-ecules are hydrogen bonded to the two-dimensional framework via the NH groups of the H(2)MIDA(-) ligands.

[1-Phenyl-2-(4-pyrid-yl)ethyl-idene]hydrazine.

The title compound, C(13)H(13)N(3), is non-planar, with the pyridine and phenyl rings inclined at an angle of 80.7 (3)°. The central ethyl-idenehydrazine atoms lie in a plane [mean deviation = 0.013 (1) Å], which forms dihedral angles of 88.5 (1) and 9.4 (1)° with the pyridine and phenyl rings, respectively. In the crystal structure, mol-ecules are linked by inter-molecular N-H⋯N hydrogen bonds into infinite chains propagating along the b axis.

3-[4-(Dimethyl-amino)phen-yl]-1-(2-pyrrol-yl)prop-2-en-1-one.

The molecule of the title compound, C(15)H(16)N(2)O, is non-planar with a dihedral angle of 16.0 (1)° between the pyrrole and benzene rings. The ketone double-bond displays an s-cis conformation with an O=C-C=C torsion angle of 7.9 (3) and an intramolecular C-H⋯O hydrogen bond. In the crystal structure, adjacent mol-ecules are paired through N-H⋯O hydrogen bonds into centrosymmetric dimers.

Ultrasonically assisted acid extraction of manganese from slag.

An ultrasonically assisted extraction (UAE) technique was developed for the extraction of manganese from electrolytic manganese slag using a sulfuric acid-hydrochloric acid mixture (4:0.3, v/v) as solvent. The UAE conditions were optimized and the significance of variables affecting UAE tested. The determination of manganese was carried out by atomic absorption spectrophotometry (AAS). The ultrasonic extraction efficiency of manganese can reach about 90% under the following optimum conditions: solvent-slag ratio: 4 mL/g; temperature: 333 K; particle size: 0.2 mm; extraction time: 35 min; amount of additive (citric acid): 8 mg/g slag. During the UAE process, the particle size parameter on the extraction was the most significant, followed by solvent-slag ratio, citric acid mass, time and temperature. The repeatability of UAE technique was satisfactory. The ultrasonic method shown to be a much superior approach to the conventional extraction method in the extraction of manganese from slag.