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The pollution and damage caused by antibiotics in water have aroused serious concern. Metal–organic frameworks (MOF), which have been hotly investigated as a novel kind of sensing materials, have been tentatively applied to the detection of antibiotics in recent years. In this work, four new Zn(II)/Cd(II) coordination polymers, [Cd(opda)(mbib)(H2O)] (1), [Cd(opda)(pbib)(H2O)] (2), [Cd(ppda)(mbib)] (3), and [Zn2(mpda)2(mbib)2]·2H2O (4), (H2opda = 1,2-phenylenediacetic acid, H2mpda = 1,3-phenylenediacetic acid, H2ppda = 1,4-phenylenediacetic acid, mbib = 1,3-bis(imidazolyl)benzene, pbib = 1,4-bis(imidazolyl)benzene), have been synthesized using bis(imidazole) and phenylenediacetate isomers under hydrothermal conditions. The flexible pda and bib ligands in 1–3 afford 2D (4,4)-connected layers, which are further stacked in an offset fashion with an ABAB sequence to propagate into a 3D supramolecular architecture through strong C–H⋯π and C–H⋯O interactions. In contrast, the flexible cis-conformation mpda and mbib ligands in 4 can be seen as “V”-type building blocks, linking Zn(II) atoms to form a 1D loop chain. The structural diversity of these complexes is mainly attributed to the different coordination modes and isomer conformations of the flexible phenylenediacetic acid and bis(imidazole) ligands. The application of the fluorescence properties of the four complexes for detecting the antibiotics cefixime (CEF) and tetracycline (TEC) and the related mechanisms have been researched. Complexes 1–4 exhibit high quenching percentages in low-concentration aqueous solutions, with values of 94.9%, 97.8%, 95.5%, and 97.2% (toward CEF) and 97.7%, 96.7%, 96.4%, and 97.4% (toward TEC), respectively. Compared with 1–3, complex 4 has a higher quenching percentage, which may be because 4 is a 3D porous supramolecular network. The detection limits of complexes 1–4 have been measured to be 0.278 μM, 0.379 μM, 0.52 μM, and 0.171 μM (for CEF) and 0.384 μM, 0.189 μM, 0.421 μM, and 0.137 μM (for TEC), which surpass/approach those of most of the reported MOF-based fluorescent sensing materials. Systematic analysis of the sensing mechanism reveals that photoinduced electron transfer and the inner filter effect contribute to the realization of the sensing process.

The SiO2 @SiO2 :Tb(1,2-BDC)3 phen microspheres with monodispersed core-shell structure, are kind of fluorescent particles, which are prepared by a seeded growth method under the catalysis of glacial acetic acid (1,2-BDC, 1,2-benzenedicarboxylic acid; phen, 1,10-phenanthroline). Firstly, silica seed was fabricated by the hydrolysis of ethyl orthosilicate, and the Tb(1,2-BDC)3 phen was prepared by using 1,2-BDC and phen. Then, a thin mesoporous silica shell doped with Tb(1,2-BDC)3 phen was grown on the prepared monodisperse silica colloids. The prepared phosphor was analyzed by Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, thermogravimetric and fluorescence spectroscopy. The experimental results showed that the diameter of the SiO2 @SiO2 :Tb((1,2-BDC)3 phen microsphere was about 200 nm with a typical core-shell structure, among which the diameter of the silica core was 180 nm, and that of the mesoporous silicon shell doped with terbium complex was about 10 nm. The fluorescence intensity of SiO2 @SiO2 :Tb((1,2-BDC)3 phen microsphere is nearly three times higher than that of Tb((1,2-BDC)3 phen complexes. The prepared microspheres could be widely used in bio-imaging, optoelectronic appliances and medical diagnosis.

A novel Sm-metal–organic framework (MOF) sensor with the molecular formula Sm8(HDBA)6·H2O has been prepared based on a penta-carboxyl organic ligand (H5DBA = 3,5-di(2′,4′-dicarboxylphenyl)benzoic acid) and samarium nitrate under solvothermal conditions. Sm-MOF is characterized by single-crystal X-ray diffraction analysis, elemental analysis, thermogravimetric analysis, and powder X-ray diffraction analysis. Structural analysis shows that the dimer metal units are alternately connected to form a one-dimensional chain, and this chain is connected by the bridging carboxyl oxygen of the ligand H5DBA to form a two-dimensional double-layer plane, which then expands into a three-dimensional microporous framework. Fluorescence detection studies show that Sm-MOF can detect Ag+ ions, MnO4– anions, and cimetidine tablets with high sensitivity and selectivity and can also be used to electrochemically detect o-nitrophenol in water. High-sensitivity detection capability of the Sm-MOF can enrich the application of samarium complexes in multifunctional sensors.

Oxycodone is one of the most prescribed narcotic medications for the treatment of moderate to severe pain in clinical practice. During long-term stability studies of oxycodone hydrochloride for injection performed as per ICH Q1A (R2) guidelines, an unknown degradation product, impurity-I, increased over time and reached a level of 0.21% after 24 months, based on the results of HPLC analysis. The observed impurity was preliminarily characterized as an oxycodone aldol dimer by using two-dimensional (2D) liquid chromatography (LC) coupled with quadrupole time-of-flight mass spectrometry (QTOF MS/MS) analysis. Impurity-I was synthesized and its molecular structure confirmed based on detailed analysis of 1D-NMR (1H, 13C, and DEPT) and 2D-NMR (1H–1H COSY, HSQC, and HMBC) spectroscopy data. The plausible mechanism for the formation of impurity-I was an aldol condensation reaction under weakly acidic conditions. In addition, the potential toxicity of impurity-I was assessed by in silico toxicity predictions using the TOPKAT software.

Six new Co(II)/Ni(II) coordination polymers, [Ni3(opda)3(mbib)4(H2O)4]·2H2O (1), [Ni(mpda)(mbib)]·H2O (2), [Ni(ppda)(mbib)]·H2O (3), [Co(opda)(pbib)(H2O)] (4), [Co(mpda)(pbib)1.5] (5), and [Co(ppda)(pbib)(H2O)2]·2H2O (6) (H2opda = 1,2-phenylenediacetic acid, H2mpda = 1,3-phenylenediacetic acid, H2ppda = 1,4-phenylenediacetic acid, mbib = 1,3-bis(1-imidazoly)benzene, and pbib = 1,4-bis(1-imidazoly)benzene), were synthesized using Co(II)/Ni(II) salts and the bis(imidazole) ligand in the presence of three different flexible phenylenediacetate isomers under hydrothermal conditions. In 1, the opda2− ligand exhibits a trans-conformation and acts as a bridging building block extending a 1D loop-containing (Ni–mbib) polymer chain into a 2D network. In 2 and 3, mpda2− and ppda2− ligands possess a cis-conformation and can be seen as a “V”-type building block, linking Ni(II) atoms to form a 1D loop-containing chain together with the mbib ligand. Utilizing the isomer bridging ligand pbib and a different metal ion, Co(II), instead of the mbib ligand and Ni(II) ion, 2D (4), 1D (5), and 2D (6) coordination polymers were obtained. The structural diversity of these complexes is mainly attributed to the different coordination modes and isomer conformations of flexible phenylenediacetic acids and the bis(imidazole) ligand. Furthermore, six Co(II)/Ni(II) coordination polymers could accelerate the degradation rate of methylene blue (MB) under visible light irradiation, especially complex 4. Complex 2 exhibited a high performance in the oxygen evolution reaction (OER). Results will provide an effective way to develop coordination polymers towards electrochemical applications.

A novel three-dimensional microporous terbium(III) metal-organic framework (Tb-MOF) named as [Tb10 (DBA)6(OH)4(H2O)5]·(H3O)4 (1), was successfully obtained by a solvothermal method based on terbium nitrate and 5-di(2',4'-dicarboxylphenyl) benzoic acid (H5DBA). The Tb-MOF has been characterized by single crystal X-ray diffraction, elemental analysis, thermogravimetry, and fluorescence properties, and the purity was further confirmed by powder X-ray diffraction (PXRD) analysis. Structural analysis shows that there are two kinds of metal cluster species: binuclear and tetranuclear, which are linked by H5DBA ligands in two μ7 high coordination fashions into a three-dimensional microporous framework. Fluorescence studies show that the Tb-MOF can detect H2O2, Fe3+, and Cr2O7 2- with high sensitivity and selectivity and can also be used for electrochemical detection of exposed 2,4,6-trinitrophenylamine (TPA) in water. The highly selective and sensitive detection ability of the Tb-MOF might make it a potential multifunctional sensor in the future.

Organic polymers have been found widespread commercial applications due to their easy processing and attractive mechanical properties. Concurrently, inorganic polyoxometalates (POMs), a class of metal-oxygen anionic and nanosized clusters of early transition metals, have a wide range of attractive functions and are used in industrial catalysis. In this communication, we report a new approach to creating the first linear poly(polyoxometalate)s that combine the advantages of polymers and POM clusters. In the experiment, a POM-containing norbornene monomer was first synthesized by linking a Wells-Dawson-type POM with a norbornene derivative. The monomer was polymerized in the presence of a Grubbs catalyst under mild conditions with yields nearly 100% in a living and controllable manner. The resulting poly(polyoxometalate)s have controllable molecular weights and a well-defined hybrid structure of an organic polynorbornene backbone with large pendant groups of the nanosized POM clusters. Thus, they form good films and have a good catalytic performance. Our findings not only pave the way for incorporating the POM clusters into polymers with well-defined structures and high molecular weights, but also offer a competitive strategy for developing more novel catalytic systems by introducing the poly(polyoxometalate)s.

A new enantioselective Michael addition between 3-(3-hydroxy-1H-pyrazol-1-yl)oxindole, a new synthon generated from isatin N,N′-Cyclic azomethine imine 1,3-dipole, and β-nitrostyrene has been discl...

An abnormal [3 + 2]-cycloaddition and highly effective and convenient one-step preparation of tetracyclic bispirooxindoles containing two all-carbon quaternary spirocenters from isatin N,N'-cyclic azomethine imine 1,3-dipole and 3-methyleneoxindole in the presence of catalytic organic base has been disclosed. A variety of bispirooxindoles bearing a dinitrogen heterocycle with four adjacent cycles have been obtained in excellent yields (up to 95%) and diastereoselectivities (>99:1) under mild conditions.

Four novel coordination polymers (CPs), {[Zn2(tbta)(phen)(OH)]·4H2O}n (1), {[Zn4(tbta)2(bpy)(OH)2(H2O)2]·7H2O}n (2), {[Cu2(tbta)(phen)(OH)]·4H2O}n (3) and [Cu2(tbta)(phen)2(OH)]n (4) (H3tbta = 1-(triazol-1-yl)-2,4,6-benzene tricarboxylic acid; bpy = 4,4′-bipyridine; phen = 1,10-phenanthroline), were synthesized and characterized by elemental analyses, FT-IR spectroscopy, and single-crystal X-ray diffraction analyses. CP 1 shows a 2D bilayer network structure based on binuclear ZnII units and (tbta)3− ligands, which are arranged in an [ABAB⋯] alternation to form 3D supramolecular structures through π⋯π stacking interactions and hydrogen bonding interactions. Noticeably, CP 2 forms a 3D network structure based on binuclear ZnII units and (tbta)3− and bpy ligands. Interestingly, the lattice H2O molecules are joined by strong hydrogen bond interactions generating (H2O)10 clusters, which make contact with the 2D network to form a 3D supramolecular structure. CPs 3 and 4 have a 2D network structure. In particular, the (tbta)3− ligands in 1–4 adopt four different coordination modes. The thermal stabilities, XRD, UV, and photoluminescence properties of CPs 1–4 were also studied. Remarkably, CP 1 is a highly selective and sensitive bifunctional luminescent sensor towards Cu2+ and Cr2O72− ions. Moreover, CPs 3 and 4 exhibit photocatalytic activities for degradation of dyes (MB/MO) under UV light irradiation.

Four coordination polymers have been synthesized by using Zn(II)/Cd(II) salt and bis(imidazole) ligand in the presence of the different flexible phenylenediacetate isomers under hydrothermal conditions. The flexible trans-conformation pda and biyb ligands in complexes 1, 3, 4 afford the 2D (4,4)-connected layer, which are further stacked in an offset fashion with an ABAB sequence to propagate into a 3D supramolecular architecture through strong C–H···π and C–H⋯O interactions. Differently, the flexible cis-conformation pda and biyb ligands in 2 can be seen as “V” type building block, linking Zn(II) atoms to form a 3D helix network. The structural diversity of these complexes is mainly attributed to the different coordination modes and isomer conformations of the flexible phenylenediacetic acids and bis(imidazole) ligand. The fluorescence property application and mechanisms of four complexes for detecting antibiotic cefixime (CEF) have been researched. Compared with 1, 3, 4 complex 2 has higher quenching percentage, this may be because 2 is a 3D structure with a large hole (18.99 × 20.02 A window). The detection limits of complexes 1–4 have been measured to be 0.23 μΜ, 0.34 μΜ, 0.37 μΜ, 0.38 μΜ, respectively. The theoretic calculation and UV–vis absorption experiments confirmed that the fluorescence quenching of complexes 1–4 toward cefixime (CEF) should be attributed to the electron transfer and the fluorescence inner filter effect between the fluorescent matter and the analyte.

One novel microporous terbium (III) framework, [Tb(DBB)(H2O)2](1), has been prepared from 4-(3,5-dicarboxylatobenzyloxy) benzoic acid (DBB) with terbium salt under hydrothermal condition. Structural analysis shows complex 1 possesses three-dimensional frameworks based on 2D double sheets linking by DBB ligands into porous channels. The gas adsorption experiments of N2 and CO2 show that complex 1 possesses microporous properties. Fluorescence analyses exhibit the characteristic luminescence of Tb3+ ion both in solid state and in aqueous. In particular, the Tb-MOF can detect acetone for its luminescence entirely quenching in acetone. Furthermore, the ionic detection experiments indicate complex 1 could be a good sensor for highly and sensitively sensing Fe3+ ion in aqueous and isopropanol, and the detection limit could reach at 10−9 M in aqueous.

Six Zn/Cd metal–organic frameworks (MOFs), {[Zn2(dppa)(bpy)2(H2O)]·H2O}n (1), {[Zn2(dppa)(phen)2(H2O)]·3H2O}n (2), [Cd(H2dppa)(bpy)]n (3), {[Cd2(dppa)(dye)]·H2O}n (4), {[Cd4(dppa)2(H2O)9]·H2O}n (5) and {[Cd2(dppa)(bpe)2(H2O)]·H2O}n (6) (H4dppa = 5-(3′4′-dicarboxylphenoxy)isophthalic acid, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine, dye = 2,2′-dipyridylamine, bpe = 1,2-bis(4-pyridy) ethane), were synthesized and structurally characterized by elemental analyses, plasma (ICP) spectrometry, IR spectroscopy, and single-crystal X-ray diffraction analyses. 1–3 are 1D ring chains. 4 shows a 2D bilayer network based on a tetranuclear cadmium cluster linked by (dppa)4− ligands. 5 displays a 2D bilayer network based on a trinuclear cadmium cluster, in which (dppa)4− ion shows two different coordination modes. In contrast to the above MOFs, 6 possesses a 3D network structure based on dinuclear cadmium units cross-linked by (dppa)4− and bpe ligands. For 1–6, weak hydrogen bonding and π⋯π stacking contacts link the discrete 1D chains or 2D networks to form high-dimensional supramolecular structures. Especially, in 1–6, (dppa)4− ligand displays seven different coordination modes and conformations, which may show natural synergy in the structural diversity of the resulting MOFs. The remarkable characteristic of these frameworks is that 2 demonstrates highly selective and sensitive bifunctional luminescent sensing towards acetone and Fe3+ ion. In addition, the thermal stabilities and luminescence properties of the MOFs were studied.

A novel 3D Cd(II) coordination polymer {[Cd(ddpa)(2,2′-bpy)]·H2O}n (1) (H2ddpa = 5,10-dioxo-5,10-dihydro-4,9-dioxapyrene-2,7-dicarboxylic acid, 2,2′-bpy = 2,2′-bipyridine) is hydrothermally synthesized in situ, and the influencing factors and mechanism for the in situ reaction are briefly discussed. The synthesis of 1 requires the formation of a new C–O ester bond. This current study confirms that metal ions and N-donor ligands play important roles in the domination of the in situ ligand from 6,6′-dinitro-2,2′,4,4′-biphenyltetracarboxylic acid (H4dbta). Furthermore, the structure, thermal stability and photoluminescent property of 1 are also investigated.

A multidentate ligand chromophore, combining rhodamine, triazole, and pyridine units, was identified and developed for the first time. Using triazole and pyridine rings as coordinating functional recognition groups, it was expected to selectively recognize Sn2+ to form some stable 5-member or 6-member rings with nitrogen and oxygen atoms. Under the optimized conditions, the ligand chromophore could selectively react with trace Sn2+ in CH3CN/H2O (99/1, v/v), accompanying with obvious changes in fluorescent spectrum, ultraviolet-visible spectrum and visual color. For fluorescent analysis, a turn-on fluorescence at 587 nm was found and increased linearly in the range of 1.2–6.2 × 10−7 mol L−1 Sn2+ from colorless to orange. For ultraviolet-visible one, a new absorption peak at 560 nm emerged with a linear range of 2.0–11.0 × 10−7 mol L−1 Sn2+ from colorless to pink. The action mechanism between the ligand chromophore and Sn2+ was confirmed basing on ultraviolet-visible titration, 1H NMR titration, Job's plot, binding constants and theoretical calculation in detail.

To early effectively detect amyloid-beta (Aβ) oligomers, a label-free reusable aptasensor was designed. This aptasensor based on a luminescent nanoscale lanthanum-based metal-organic framework (L-MOF)-armored single-stranded DNA antibody (MOF-armored-anti-DNA antibody) as signal tags and aptamer bound to magnetic beads (Apt-MB) as capture probe. The reusable aptasensor combines signal tag and capture probe with antigen-antibody interaction. When the reusable aptasensor is formed, the strong fluorescence intensity of L-MOF will "turn off" by photo-induced electron transfer from excited states to an unfilled d shell of iron cations on the nanoparticle surface. Upon the presence of Aβ oligomers in serum samples, they can be especially distinguished with the Aβ oligomers aptamer in capture probes and then signal tags are released into the solution for developing the fluorescence aptasensor under excitation/emission 365 nm/430 nm. Meanwhile, the aptamer was recovered from the complex of Aβ oligomers/Apt-MB by heat treatment. When the temperature returns to room temperature, the recovered aptamer in the capture probe can once again bound to the MOF-armored-anti-DNA antibody for reuse. The label-free reusable aptasensor system detection has high sensitivity and selectivity toward Aβ oligomers (LOD = 0.4 pg/mL) and an excellent linear range (0.001-100 ng/mL). This strategy is a fruitful step for the development of reusable aptasensor and may turn on new avenues for the applications of Aβ oligomer detection in clinical diagnosis.Graphical abstract.

Phenylethanoid glycosides (PhGs) are compounds made of phenylethyl alcohol, caffeic acid and glycosyl moieties. The first published references about phenylethanoid glycosides concerned the isolation of echinacoside from Echinaceu ungustifolia (Asteraceae) in 1950 and verbascoside from Verbascum sinuatum (Scrophulariaceae) in 1963. Over the past 60 years, many compounds with these structural characteristics have been isolated from natural sources, and most of these compounds possess significant bioactivities, including antibacterial, antitumor, antiviral, anti-inflammatory, neuro-protective, antioxidant, hepatoprotective, and immunomodulatory activities, among others. In this review, we will summarize the phenylethanoid glycosides described in recent papers and list all the compounds that have been isolated over the past few decades. We will also attempt to present and assess recent studies about the separation, extraction, determination, and pharmacological activity of the excellent natural components, phenylethanoid glycosides.

Two novel coordination polymers (CPs), formulated as {[Zn3(L)1.5(DMF)3]•C2H7N} n (1), and [Zn(L)0.5(bpb)0.5(H2O)2] n (2), (H4L = 1, 1′-ethylbiphenyl −3, 3′, 5, 5′- tetracarboxylic acid, bpb = 1, 4-di(pyridin-4-yl) benzene), have been acquired under hydrothermal conditions. Complexes 1 and 2 display excellent luminescence characteristics and stability in antibiotics and organic solvents. Complex 1 can detect triethylamine (TEA) and tetracycline (TET) in water by fluorescence quenching. The detection limits of 1 towards TEA and TET are 1.07 μM and 0.1 μM, respectively. Complex 2 can be used as a luminescence sensor to detect nitrobenzene (NB) and the detection limit towards NB is 0.2 μM. Moreover, complexes 1 and 2 perform excellent reproducibility, because the changes of fluorescence intensity are negligible after four cycles. The mechanism of the fluorescence quenching is discussed in detail.

Four new Zn(II) coordination complexes, [Zn(opda)(obiyb)] (1), [Zn(opda)(pbiyb)0.5] (2), [Zn(opda)(mbib)]·H2O (3), [Zn(opda)(pbib)] (4), (H2opda = 1,2-phenylenediacetic acid, obiyb = 1,2-bis(imidazol-1-ylmethyl)benzene, pbiyb = 1,4-bis(imidazol-1-ylmethyl)benzene, mbib = 1,3-bis(1-imidazoly)benzene, pbib = 1,4-bis(1-imidazoly)benzene), have been synthesized by using zinc salt and 1,2-phenylenediacetic acid in the presence of different bis(imidazole) ligands under hydrothermal conditions, and characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and powder X-ray diffraction (PXRD) analysis. For all of complexes, the Zn(II) atom has the same (ZnO2N2) tetrahedrally coordinated geometry, however, they show diverse structure network. The flexible bis(imidazole) ligands in 1 and 2 afford the 2D corrugated layer, which are further stacked in an offset fashion with an ABAB sequence to propagate into a 3D supramolecular architecture through strong C–H⋯π and C–H⋯O interactions. Differently, the rigid bis(imidazole) ligands in 3 and 4 give rise to the 3D porous network. Furthermore, the relationship between molecular conformation, packing modes and fluorescence properties have also been investigated.

Four new Zn(II) and Cd(II) coordination complexes, [Zn(p-pda)(m-bib)]·H2O (1), [Zn(m-pda)(o-bib)]·H2O (2), [Cd(o-pda)(o-bib)] (3), [Cd(m-pda)(o-bib)]·H2O (4), (H2pda = phenylenediacetic acid, bib = 1,4-bis(imidazol-1-ylmethyl)benzene), have been synthesized, and structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography. Complex 1 exhibits a 3D porous network based on 2D loop-containing layer. Complex 2–4 possesses a 3D network extended by 2D net. Differently, in complex 3, the 2D network stack in an ABAB mode, while equivalent wave-like 2D networks mutually interpenetrated with each other to generate a 2D → 3D entangled system in 2 and 4. Furthermore, the relationship between molecular conformation, packing modes and fluorescence properties have also been investigated.

The objective of this study was to develop a ratiometric and colorimetric organic sensor for Pb2+ detection in environmental samples. A new probe 4-phenyl amino thiourea (PAT) was designed and synt...

Three new manganese 4'-(3,5-dicarboxyphenyl)-2,2':6',2'''-terpyridine (H2DATP) metal-organic framework materials have been generated through regulating the ratios of a binary solvent mixture (DMA/H2O) under solvothermal conditions. Compound 1 {[Mn2(DATP)(HDATP)(H2O)4](OH)·10H2O}n displaying a one-dimensional (1D) chainlike structure was crystallized from the DMA/H2O mixture with a molar ratio of 1 : 1, while the two-dimensional (2D) layer species, {[Mn(DATP)(H2O)]·2H2O}n (2) was produced by increasing the ratio of DMA/H2O to 5 : 1. Interestingly, the crystallization in pure DMA yields a three-dimensional (3D) interpenetrating network {[Mn(DATP)]·4H2O}n (3), featuring higher solvent stability and pH stability than compounds 1 and 2. It is proved that solvent not only influences the structural transformation process of crystals but also has a significant effect on their properties. These three compounds present different catalytic performances in the CO2 cycloaddition to epoxides with various substituent groups into corresponding cyclic carbonates, and only 3 can serve as an efficient and recyclable catalyst at mild temperature.

Five novel nickel(II) coordination polymers, namely, [Ni(cpna)(4,4′-bipy)(H2O)2] (1), [Ni(cpna)(1,4-bbi)(H2O)]·H2O (2), [Ni4(cpna)4(H2O)8] (3), [Ni2(cpna)2(4,4′-bbpy)(H2O)] (4), and [Ni (cpna)(1,4-bibz)0.5(H2O)]·H2O (5) (H2cpna = 5-(4′-carboxylphenyl)nicotinic acid; 4,4′-bipy = 4,4′-bipyridine; 1,4-bbi = 1,4-bisbenzimidazole; 4,4′-bbpy = 4,4′-bis(imidazol-1-ylmethyl)biphenyl; 1,4-bibz = 1,4-bis(1-imidazoly)benzene), have been synthesized under hydrothermal conditions based on H2cpna and four different linear N-donor co-ligands. Structural analyses show that all Ni(II) ions lie in slightly distorted six coordinated octahedral geometries. Complexes 1–5 exhibit a variety of architectures: 1 features a 1D chain structure, complex 2 possesses a 2D network, and compounds 3–5 display a 3D framework with dimer Ni2 units, which might be affected by the coordination modes and lengths of the co-ligands. The magnetic and photocatalytic properties were investigated. The variable-temperature magnetic susceptibilities indicate that weak ferromagnetic interactions exist between two adjacent Ni(II) ions of 2, while the other compounds show antiferromagnetic exchange interactions. All of them could accelerate the degradation rate of MO under visible light irradiation, especially compound 2.

Weeds bring severe threats to agricultural production and most traditional herbicides cause serious pollution to the environment. Caffeic acid is a potential allelochemical of many crops. To develop novel herbicides, a series of trans -caffeic acid analogues were prepared to evaluate their growth inhibition on S. viridis and investigate structure-activity relationships. Presence of hydroxyl groups on the benzene ring greatly reduced the phytotoxicity of analogues and the double bond seemed not to be necessary. Moreover, it was found that halogenated cinnamic acid analogues showed potent inhibitory activity. 4-Fluorocinnamic acid (4-FCA) displayed the strongest growth inhibition in a concentration-dependent manner, whereas it induced significantly weaker inhibition on wheat. This selectivity could help us to develop a novel herbicide. Exposure of S. viridis to 4-FCA increased levels of H 2 O 2 and catalase (CAT) in roots, suggesting that the inhibitory effect of 4-FCA might be related to oxidative stress. Thus, we have found an active lead compound for a novel herbicide derived from crop allelochemicals, which may help in the development of new environmentally safe herbicides.

Autotoxicity is considered as a major factor causing replant problems. As one of the most frequently used herbs in traditional Chinese medicine and industrial crop, Glycyrrhiza uralensis Fisch. is cultivated extensively in north of China, but it has often been hampered by replant failure. In light of the serious threat of replant failure, the allelochemicals from Glycyrrhiza uralensis Fisch. and their allelopathic effects were investigated. Extract of Glycyrrhiza uralensis Fisch. rhizosphere soil showed phytotoxic activity against Lactuca sativa and autotoxic activity on its own seedlings. Six compounds were isolated from the extract and elucidated by spectroscopic analysis. Among them, liquiritin (1), isoliquiritigenin (2) and glycyrrhizic acid (4) showed observably phytotoxicity and autotoxicity. They were further verified and quantified in the rhizosphere soils of Glycyrrhiza uralensis Fisch. by high-performance liquid chromatography (HPLC), and their concentrations in dry soils were 2.32, 0.09 and 12.5 μg/g, respectively. These allelochemicals, showed remarkably phytotoxic and autotoxic activity, may play an important role in the replant failure of Glycyrrhiza uralensis Fisch.

A visualization strategy is described for the detection of clenbuterol (CLB). It is using of antibody against dsDNA and G-quadruplex/hemin labeled on a metal organic framework of type MIL-101(Fe) (G-quadruplex/hemin-anti-DNA/MIL-101) acting as a peroxidase mimetic, and magnetic beads modified with aptamer and complementary DNA (MB/Apt-cDNA) as capture probes. The detection reagent was prepared via the reactions between the double stranded DNA (Apt-cDNA) in capture probes and anti-DNA in peroxidase mimetic. In the presence of CLB, the aptamer on the magnetic beads preferentially binds CLB, and the peroxidase mimetic is released to the supernatant after magnetic separation. The released peroxidase mimetic can catalyze the TMB/H2O2 chromogenic system under mild conditions. This leads to the development of a blue-green coloration whose absorbance is measured at 650 nm. The detection limit is as low as 34 fM of CLB. The method was applied to the determination of CLB in pork samples and gave results that were consistent with data obtained with an ELISA kit.

A catalytic asymmetric nitroso aldol intramolecular transesterification cyclization domino reaction between a C3 alkyl ester substituted oxindole and nitrosobenzene for the construction of chiral spirooxindoles was achieved in the presence of a chiral bifunctional tertiary amine thiourea catalyst and water. Optically active spirooxindoles were obtained in moderate yields (up to 76 %) and excellent enantioselectivities (up to 95 % ee).

A series of MDI-50 based non-ionic waterborne polyurethane dispersions (MDI-NPUD) were prepared by the mixing of 2,4’-diphenylmethane diisocianate (2,4’-MDI) and 4,4’-MDI (MDI-50) which reacted with hydroxylated tung oil (HTO) and polyethylene glycol-800 (PEG-800), Fourier Transform Infrared Spectroscopy (FTIR) and Proton-Nuclear Magnetic Resonance (1H-NMR) were used to characterize and analyze their molecular structures. The results indicated that MDI-50 and HTO were introduced as hard segment while PEG acted as soft segment. The surface tension, Hydrophile-Lipophile Balance (HLB) and stability were investigated. All MDI-NPUDs had much lower surface tension than the dicyclohexyl methane diisocyanate (HMDI) based NPUD (HMDI-NPUD). By changing the feed ratio of MDI-NPUD, the properties of MDI-NPUD could be controlled

The diffusion reaction of 1,4-bis(1,2,4-triazol-1-yl)butane (btb) with Co(II)/Ni(II) ions as well as counter anions (PF6−) yielded two new coordination polymers, [Co1.5(btb)4.5](PF6)3 (1) and [Ni2(btb)6](PF6)4 (2). Both complexes have 3D uninodal 6-connected (412,63) net topology, forming triple interpenetrating structure. The distance between adjacent metal ions via btb bridging ligand is in the range of 13.930–14.181 A and 13.982–14.086 A, respectively. The magnetic behaviors of complexes 1 and 2 have been analyzed by one-ion approximation with spin–orbit coupling and zero-field splitting, respectively.

2-(4-((4-Chloro-6-((3',6'-dihydroxy-3-oxospiro [isoindoline-1,9'-xanthen]-2-yl)amino)-1,3,5-triazin-2-yl)amino)benzoyl)-N-phenylhydrazine-1-carbothioamide (PCFH) is prepared for the detection of Hg2+ by hydrogen-induced emission (HIE). In the presence of blood serum, PCFH has a strong fluorescence response to Hg2+ in ethanol/H2O (90/10, v/v), while the fluorescence with other metal ions, including Cu2+, is much weaker. PCFH coordinates better with Hg2+ than Cu2+, which gives rise to specificity of detection. Through spectroscopic techniques and molecular dynamics simulations, the mechanism of HIE reveals that the interactions between polar bonds of PCFH and protein in blood serum via hydrogen bonding can efficiently enhance the specificity and sensitivity of detection. As the results of the interactions, the free rotation of two plenary structures of PCFH linked by C C bonds is restricted, which leads to increased planarity, and the protein destroys the coordination between Cu2+ and PCFH. The development of cells under Hg2+ pollution is monitored, and the concentrations of Hg2+ in deformed and dead cells are 0.47 μM and 0.88 μM respectively. The HIE effects found here will promote new ideas in the design of new types of fluorescence probes for Hg2+ and other metal ions.

Dihydrofolate reductase (DHFR) is a crucial enzyme in the folate metabolic pathway that is necessary for the biosynthesis of thymidylate, purine nucleotides, methionine, serine, and glycine require...

Two novel lanthanide coordination polymers, {[Ln(stp)(bipy)(H2O)]·(H2O)}n [Ln = Eu (1) and Dy (2)], were synthesized by hydrothermal reactions of 2-sulfoterephthalate (stp) and 4,4′-bipyridine (bipy) ligands with europium/dysprosium(III) salts. Structural analyses show that both complexes 1 and 2 are isomorphic and crystallize in the monoclinic crystal system with space group P21/n. Complex 1 exhibits a two-dimensional grid-like structure from europium(III) ions bridged by the carboxyl and sulfonate groups of stp ligands. Notably, the stretching 4,4′-bipyridine ligands besides the 2D grid-like layers form π···π interactions and interpenetrate into the empty voids of another adjacent layer into a twofold interpenetrated structure. Fluorescence analysis show that the emission of two complexes exhibit the characteristic peaks of lanthanide ions.

Four new pregnane glycosides 1–4 were isolated from the ethanol extract of the stem of Gymnema sylvestre and named gymsylvestrosides A–D. Hydrolysis of compound 1 under the catalysis of Aspergilus niger β-glucosidase afforded compound 5 (gymsylvestroside E). Their structures were determined by spectroscopic methods such as HRESIMS, 1D and 2D NMR, as well as HMQC-TOCSY experiment. Compounds 1–4 were screened for Saccharomyces cerevisiae α-glucosidase inhibitory activity.

Two lanthanide complexes with the formula [Dy(3-Cl-4-MOBA)3phen]2 (1) and [Eu (3-Cl-4-MOBA)3phen]2 (2) (3-Cl-4-MOBA=3-chloro-4-methoxybenzoate; phen=1,10-phenanthroline) were synthesized and characterized by elemental analysis, molar conductivity, ultraviolet spectra, infrared spectra, single crystal X-ray diffraction, and thermal analysis. The two complexes are isostructural. Two lanthanide cations are connected by four carboxylic groups through a bridging bidentate mode, resulting in distorted square-antiprism geometry. Under the excitation ultraviolet light, the two complexes exhibit characteristic emission of dysprosium or europium cation. The gaseous decomposition products of the two complexes were inferred by thermogravimetry and infrared spectrometry techniques. The heat capacity of the complexes was measured using differential scanning calorimetry technology. And the thermodynamic functions including entropy, gibbs free energy, and enthalpy relative to the reference temperature (298.15 K) were also calculated. In addition, the antifungal activities of the two complexes were also studied.

Baicalin is a flavonoid compound isolated from Scutellaria baicalensis, a Chinese traditional medicinal herb, and is used as an anti-inflammatory, antibacterial, anxiolytic and hepatoprotective drug. Accumulating evidence has demonstrated that baicalin exhibits potent antitumor properties by suppressing cell growth, arresting cell cycle progression and inducing differentiation or apoptosis in leukemia cell lines. However, whether or not the extrinsic pathway is involved in baicalin-induced apoptosis of leukemia cells and the mechanisms underlying the antitumor activity of baicalin remain unclear. In the present study, the effect of baicalin on the expression of caspase-8, Fas cell surface death receptor (Fas) and Fas ligand in HL-60 cells was assessed, and it was demonstrated that the Fas-mediated extrinsic pathway was also involved in baicalin-triggered cell apoptosis, in addition to the intrinsic pathway. Furthermore, baicalin was able to inhibit the proliferation of HL-60 cells by arresting the cell cycle at the G0/G1 phase, and by down-regulating Myc proto-oncogene protein (c-Myc) along with its target gene, human telomerase reverse transcriptase. In summary, the results of the present study demonstrated that baicalin was able to inhibit the growth of HL-60 cells through blockade of the G0/G1 phase of the cell cycle, and significantly induce the apoptosis of cells by activating the intrinsic and extrinsic pathways. The inhibition of HL-60 cell growth was also demonstrated to be mediated by telomerase inhibition through suppression of c-Myc. The results of the present study highlight the possibility of baicalin as a promising regimen for the treatment of AML.

A new isatin N,N′-cyclic azomethine imine 1,3-dipole was devised, and an unusual Michael addition with β-nitrostyrene catalyzed by tributylamine under mild conditions has been developed. The new reaction featured the C3 umpolung of oxindole and an unusual formation of double bond. Notably, this new synthon performed as a donor rather than an acceptor. This protocol provided a promising method for the preparation of various 3-aminooxindoles with good yields in moderate diastereoselectivities.

An unusual and highly effective asymmetric annulation of nitrosoarenes with hydroxymaleimides catalyzed by a chiral bifunctional amine squaramide catalyst has been disclosed. A wide range of highly fused chiral N-hydroxyindolines with two consecutive quaternary stereocenters and multifunctional groups were directly and effectively prepared in excellent yields (up to >99%) with complete regioselective cyclization and excellent stereoselectivities (up to >99:1 dr and >99% ee). The efficiency and potentials of the new reaction and the target chiral entities were well demonstrated by delicate transformations into a series of new chiral indolines.

Three new tigliane-type diterpene esters, 1–3 with unusual 7-oxo-5-ene or 7-hydroxy-5-ene moieties in their skeletons, were isolated from the leaves of Croton tiglium. Their structures were unambiguously elucidated on the basis of spectroscopic data.

A series of lanthanide complexes [Ln(4-Cl-2-MOBA)3phen]2 (Ln=Sm (1), Nd (2), Ho (3), Eu (4), Dy (5), and Tb (6); 4-Cl-2-MOBA=4-chloro-2-methoxybenzoate, phen=1,10-phenanthroline) were synthesized and characterized. The single-crystal X-ray diffraction demonstrates that 1–3 are isomorphous, which present dimeric structures with four 4-Cl-2-MOBA anions function as bridging ligands. Complexes 1 and 4–6 display their characteristic luminescence emission bands of central Ln3+ ions. The heat capacities, the thermodynamic functions and the thermogravimetry–Fourier transform infrared spectra of gaseous products of complexes 1–6 were investigated. Their non-isothermal kinetics of the second decomposition stage was studied by the integral isoconversional non-linear method and Stark method. Furthermore, 1–6 exhibited excellent antibacterial activity against Candida albicans, Escherichia coli and Staphylococcus aureu.

Three new Cd(II) complexes, [Cd(bic)(adp)0.5] (1), [Cd(mbic)(adp)0.5]·H2O (2) and [Cd(hbic)(adp)0.5]·H2O (3) (Hbic = 1H-benzoimidazole-5-carboxylic acid, Hmbic = 2-methyl-1H-benzoimidazole-5-carboxylic acid, Hhbic = 2-hydroxyethyl-1H-benzoimidazole-5-carboxylic acid, H2adp = adipic acid), have been prepared by the hydrothermal reaction of adp2− with Cd(II) ions in the presence of different benzimidazole carboxylic acids. 1 exhibits a 3D framework constructed from 1D infinite [Cd(COO)]n units which are connected by adp in a trans-(κ2-κ1)-(κ2-κ1)-μ4 mode and bic in a novel trans-(κ1-κ1)-(κ1)-μ3 mode. 2 features an unusual [Cd2(COO)4] paddle-wheel dinuclear secondary building unit (SBU), which is bridged into a 2D sheet by adp in a (κ1-κ1)-(κ1-κ1)-μ4 mode and mbic in a cis-(κ1-κ1)-(κ1)-μ3 mode. For 3, the metal centre is connected into a 1D double chain by hbic in a (κ1)-(κ1-κ1)-μ2 mode, which is further linked by the trans-(κ2-κ1)-(κ2-κ1)-μ4 adp to form a 2D layer architecture. The luminescence properties in the solid state at room temperature of compound 1–3 are almost the same as the free ligand.

Four lanthanide complexes with a general formula [Ln(3,5-DmeoxBA)3(phen)]2 (Ln = Tb(1), Dy(2), Er(3), Yb(4); 3,5-DmeoxBA = 3,5-dimethoxybenzoic acid; phen = 1,10-phenanthroline) were synthesized and characterized by elemental analysis, infrared spectra (IR), and thermogravimetric, differential scanning calorimetry techniques, combined with Fourier transform infrared (TG/DSC–FTIR) technology. The thermal decomposition processes of the four complexes were investigated by TG/DSC–FTIR techniques. Heat capacities were measured by DSC. The values of the experimental heat capacities were fitted to a polynomial equation with the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions (HT − H298.15 K), (ST − S298.15 K), and (GT − G298.15 K) were calculated. The antibacterial action of the four complexes on bacteria and fungus such as Escherichia coli, Staphylococcus aureus and Candida albicans were studied by filter paper approach. The luminescent properties of the complexes 1 and 2 were also studied.

Vascular endothelial growth factor (VEGF) plays an important role in solid tumor growth, progression and metastasis as well as in the proliferation and differentiation of hematological malignancies. However, the molecular mechanism that modulates VEGF expression and secretion in leukemia cells has not yet to be elucidated. The purpose of the present study was to investigate the role of the signal pathway in modulating the expression of VEGF in HL-60 cells. Specific siRNAs targeting VEGF were transfected into HL-60 cells and the VEGF expression was measured with reverse transcription-polymerase chain reaction (RT-PCR) and western blot assay. The cell proliferation of HL-60 cells was detected by the cell counting kit-8 (CCK-8) assay and the differentiation of HL-60 cells induced by all-trans-retinoic acid (ATRA) was detected by the RT-PCR assay and flow cytometry assay for CD11b. The upstream transcription factors that were related to VEGF expression such as P53, SP-1, c-jun, VHL, cox-2, c-myc and stat3 were detected by RT-PCR assay. In addition, the chromatin immunoprecipitation (ChIP) assay was used to reveal the role of c-myc by binding the target gene VEGF. The results demonstrated the hypoxia-inducible factor 1α-related signaling pathway, not the same as in solid tumors, might not play a key role in modulating VEGF expression. c-myc contributes to the modulation of VEGF expression by targeting the promoter of VEGF, which was indicated by the ChIP assay. In conclusion, our data demonstrate that VEGF plays an important role in the differentiation and proliferation of HL-60 cells; c-myc-dependent downregulation of VEGF induced by ATRA contributes to the differentiation of HL-60 cells.

In this review, we have highlighted the adverse drug reaction mediated by transporters from two aspects: (1) competitive interactions between drug and drug/metabolite/endogenous substance mediated by transporters; (2) the expression/function change of transporter due to physiologic factors, disease, and drugs induction. It indicated that transporters exhibited a broad substrate specificity with a degree of overlap, which could change the pharmacokinetics of drugs and cause toxicity due to competition interactions among substrates. In addition, the expression and function of transporters were regulated by physiological conditions, pathological conditions, and drugs induction, which could cause adverse drug reaction and interindividual differences. Furthermore, one substrate was always medicated by several transporters and often subjected to metabolism by CYP enzymes, so we should be more aware of the increased plasma concentration of drugs caused by drug transporters as well as drug metabolizing enzymes synergistically, especially for drugs with narrow therapeutic window. In addition, the weightiness for one transporter to induce drugs plasma/tissue concentration change could be different in different condition. On the whole, transporters were corresponding with systemic/organs exposure of drug/metabolites/endogenous compounds. So understanding the expression and function in drug transporters will result in better strategies for optimal dosage regimen and reduce the risk for drug adverse reaction as well as adverse drug-drug interactions.

An organic molecular system with proton-tunable photoluminescence properties based on a mono-substituted bipyridinium derivative 1-(3-carboxybenzyl)-4,4′-bipyridinium chloride, which possesses both pyridine and carboxylic acid groups as proton-responsive units, has been developed. Through controlling the pH value of the self-assembled systems, three compounds with different degrees of protonation have been obtained. These compounds display distinctly different luminescence behaviors and undergo solid-state structural conversion in response to changes in pH values. In particular, luminescence switching triggered by acid–base vapor can be realized.

Stellera chamaejasme, a perennial weed which is an ecological threat, is widely distributed in some grasslands of Central and Eastern Asia. Our previous studies have identified several allelochemicals including two coumarins (umbelliferone and daphnoretin), from S. chamaejasme, and confirmed that allelopathy contributed to the competitive behavior of this weed. In this study, the inhibitory effects of umbelliferone and daphnoretin on lettuce seedlings and the mechanisms of their phytotoxicity were investigated. Results showed that shoot and root elongation and fresh weight of lettuce seedlings were effectively inhibited by umbelliferone in a concentration-dependent manner. Daphnoretin showed a weaker phytotoxicity. Both of the coumarins arrested the mitosis process in lettuce root tips and induced proline overproduction. Additionally, loss of cell viability and overproduction of reactive oxygen species in lettuce root cells were found after treatments with umbelliferone. Moreover, umbelliferone caused lipid peroxidation. These results suggested that umbelliferone displayed stronger phytotoxicity than daphnoretin on lettuce growth, and that the two coumarins had different mechanisms of phytotoxicity. That of daphnoretin was mainly dependent on its inhibitory effects on mitosis. Umbelliferone caused membrane lipid peroxide formation and cell death by inducing ROS overproduction, and impacted cell division, which resulted in growth inhibition of the receptor plant.

Chiral diamine catalysts 11a-e derived from α,α-diphenyl prolinol were prepared and successfully applied to the Michael addition of aromatic oximes to α,β-unsaturated aldehydes in mediocre to good yields (up to 78%) and good to high enantioselectivities (up to 93% ee).