Cui-Juan Wang

A series of intriguing metal–organic frameworks with 3,3′,4,4′- benzophenonetetracarboxylic acid: structural adjustment and pH-dependence

To understand the influence of the pH parameter on crystal growth, six compounds prepared at different pH values have been explored, namely {Cu(H2bptc)(bpa)(μ2-H2O)}n (1) {[Cu3(Hbptc)2(bpa)3(H2O)8]·4H2O}n (2), {[Cu2(bptc)(bpa)2(H2O)]·6.5H2O}n (3), {[Mn2(bptc)(bpa) (μ2-H2O)(H2O)5]·H2O}n (4), {[Co2(bptc)(bpe)(μ2-H2O)(H2O)5]·H2O}n (5) and {[Mn2(bptc)(bpe) (μ2-H2O)(H2O)5]·H2O}n (6) (H4bptc = 3,3′,4,4′- benzophenonetetracarboxylic acid, bpa = 1,2-bis(4-pyridy)ethane and bpe = 1,2-bis(4-pyridy)ethene). The structure of 1 displays a 3D open rhombic framework based on an infinite metal-aqua chain. Compound 2 contains two different motifs: a cationic 1D chain of [Cu(bpa)(H2O)4]2+, and an anionic 2D network of [Cu2(Hbptc)2(bpa)2(H2O)4]2−. Compound 3, a microporous open-framework structure, presents an uncommon 3D, trinodal, 4-connected self-penetrating network. Compounds 4, 5 and 6 present the same arrangement with 4,6-connected 3D networks. Comparing the experimental results, it is clear that the pH value plays a crucial role in the formation of the resulting structures. The thermal stabilities of compounds 1–6 are discussed. The magnetic properties for 2 and 4 are also studied and they both exhibit a weak antiferromagnetic coupling through the O2C–C–C–CO2 bridge and μ2-aqua bridge, respectively.

Pyrrolizidine alkaloids from Liparis nervosa with inhibitory activities against LPS-induced NO production in RAW264.7 macrophages.

Six pyrrolizidine alkaloids were isolated from the whole herb of Liparis nervosa together with two previously known ones. Their structures were elucidated by extensive spectroscopic analyses and chemical reactions. The cytotoxicity of the isolates was evaluated against A549, HepG2, and MCF-7 human cancer cell lines; however, no significant growth inhibition was observed. All compounds were evaluated for the inhibition of LPS-induced nitric oxide (NO) production in RAW264.7 macrophages, and most significantly inhibited NO production with IC50 values in the range of 2.16-38.25 μM.

Five new nervogenic acid derivatives from Liparis nervosa

Ten new nervogenic acid derivatives (1-4, 6-11) and one known compound (5) have been isolated from Liparis nervosa. Their structures were determined using extensive spectroscopic analysis, including 1D and 2D NMR experiments. Compounds 3, 4, 9, 10, and 11 were evaluated for their cytotoxicity against A549, H460, Hela, MCF-7, Caco2, and HepG2 human cancer cell lines.

Structures and theoretical studies of three copper(II) complexes containing 2,2′-dipyridylamine and acrylato or methylacrylato ligands

A series of new complexes of copper(II): [Cu(CH2=C(Me)CO2)2(dpa)]·H2O (1), [Cu(CH2=CHCO2)2(dpa)]·H2O (2), Cu(CH3CH=CHCO2)2(dpa)(H2O) (3) (dpa = 2,2′-dipyridylamine) have been prepared and characterized by elemental analysis, IR spectra, thermal analysis, density functional theory (DFT) calculations and X-ray structure analysis. The crystal structures of 1 and 2 consist of neutral [Cu(L)2(dpa)] (L = CH2=C(Me) and CH2=CH ) units and one lattice water molecule in the unit cell, while in 3 the water molecule is found to coordinate to copper(II). The mononuclear units of 1 and 2 are linked via a similar triple-hydrogen-bonding uncoordinated water molecule into different supramolecular structures, 1D double chains for 1 and a 2D supramolecular network for 2. A detailed crystal structure analysis of 2 revealed that the presence of the C–H ··· O and C–H ··· C hydrogen bonds appear to be responsible for the difference in supramolecular structures differences between 1 and 2. In 3, 1D double chains are formed through hydrogen bonds and weak π–π stacking along the a-axis. In this context, we addressed the questions concerning the molecular energies, stabilities and atomic charges. The DFT calculation results proved that the water molecules coordinate to copper(II) atoms in complex 3, while the water molecules in complexes 1 and 2 are free.

A novel steroidal alkaloid from Fritillaria shuchengensis

A novel steroidal alkaloid, suchengbeisine (1), along with two known steroidal alkaloids, N-oxide of verticinone (2) and zhebeininoside (3), were isolated from the bulbs of Fritillaria shuchengensis S. C. Chen et S. F. Yin. The structures of these compounds were elucidated by intensive spectroscopic methods, including NMR, IR, CD and MS.

Identification of a new flavone glycoside from Codonopsis nervosa

A new flavone glycoside, luteolin 7-O-[(6″′-caffeoyl)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranoside (1), was isolated from Codonopsis nervosa, along with three other known compounds, luteolin 7-O-β-D-glucopyranoside (2), luteolin 7-O-gentiobioside (3), and tangshenoside VI (4). Their structures were determined on the basis of 1D and 2D NMR, IR, and HR-ESI-MS.

Synthesis and characterization of a nickel-organic framework encapsulating hetero-chiral helical water chains in the 1-D channels

A porous coordination polymer based on nickel(II) and rigid multitopic ligands, {[Ni(dpdapt)(BDC)(H2O)] · 3.5H2O} n (1) (dpdapt = N, N′-di(2-pyridyl)-2,4-diamino-6-phenyl-1,3,5-triazine), has been synthesized and characterized. Compound 1 crystallizes in the space group C2/m and possesses a 3-D open framework with 1-D rhombic hydrophilic channels, in which hetero-chiral helical water chains are located. Two 1-D water chains are further stabilized by hydrogen-bonding interactions with the host, inducing a 10-oxygen ring propagated along the channel. TGA, PXRD analyses, and magnetic properties have also been studied.

Eremophilane derivatives from Senecio dianthus

From the aerial parts of Senecio dianthus, five eremophilane glucosides (1, 2, 4–6) and one new eremophilenolide (7) were isolated, together with sixteen known compounds (3, 8–22). Their structures and relative configurations were elucidated on the basis of extensive spectroscopic analysis, including HR-ESI-MS, X-ray, CD, 1D- and 2D-NMR experiments.

Diaqua­bis­{3-[4-(1H-imidazol-1-yl)phenyl]-5-(pyridin-2-yl-κN)-1H-1,2,4-triazol-1-ido-κN1}zinc

The centrosymmetric molecule of the title compound, [Zn(C16H11N6)2(H2O)2], contains one Zn2+ ion located on a center of symmetry, two 3-[4-(1H-imidazol-1-yl)phenyl]-5-(pyridin-2-yl)-1H-1,2,4-triazol-1-ide (Ippyt) ligands and two coordinating water molecules. The ZnII ion is six-coordinated in a distorted octahedral coordination geometry by four N atoms from two Ippyt ligands and by two O atoms from two water molecules. Adjacent units are interconnected though O—H⋯N hydrogen bonds, forming a three-dimensional network.

Four Ln-coordination polymers: Synthesis, crystal structure, fluorescent sensing of nitrobenzene and Tb3+, and catalytic properties

Abstract In many sensing and catalytic applications, the target molecule is required to be carried in an effective manner in a specific condition. Metal-organic frameworks (MOFs) have high porosity, large surface area, and tunable functionality and are promising carriers for such purposes. Current approaches to detect Tb3+ and reduce 4-nitrophenol (4-NP) are based on multistep methods. We synthesized a series of coordination polymers (1–4) with excellent fluorescence and catalytic activity. Moreover, 1 and 2 exhibit significantly higher fluorescence than other compounds, indicating that 1 and 2 could be efficient multifunctional fluorescence probes for high-sensitivity sensing of nitrobenzene, and 1 can be used as a highly sensitive fluorescent sensor to detect Tb3+, with a detection limitation of 5 × 10−7 M. In addition, the as-prepared Ag@compound 1 shows remarkable catalytic performance to reduce 4-NP, with a reduction rate constant k as large as 2.07 × 10−2 s−1.