Search

Background: Natural products (NPs) are important sources for the design of new drugs and agrochemicals. Neopeltolide, a marine NP, has been identified as a potent Qo-site inhibitor of cytochrome bc1 complex. Methods: In this study, a series of neopeltolide derivatives was designed and synthesized by the simplification of its 14-membered macrolactone ring with a diphenyl ether fragment. The enzymatic inhibition bioassays and mycelium growth inhibition experiments against a range of fungi were performed to determine their fungicidal activities. Results: The derivatives have potent activity against the porcine bc1 complex. Compound 8q showed the best activity with an IC50 value of 24.41 nM, which was 8-fold more effective than that of positive control azoxystrobin. Compound 8a exhibited a 100% inhibitory rate against Zymoseptoria tritici and Alternaria solani at a 20 mg/L dose. Conclusion: Computational results indicated that compounds with suitable physicochemical properties, as well as those forming a hydrogen bond with His161, would have good fungicidal activity. These data could be useful for the design of bc1 complex inhibitors in the future.

We developed a bubble-free electroosmotic pump (EOP) with polyaniline-wrapped platinum-coated titanium mesh electrodes. These electrodes prepared by the chronopotentiometry (CP) method show a better redox performance, electrochemical activity and stability. The optimal CP parameters are 0.413 mA of anode current (current density, 1.5 mA/cm2), and 1800 s of anode time (polymerization time). The EOP, assembled with polyaniline-wrapped platinum-coated titanium mesh electrodes, shows a much better performance than that of platinum-coated titanium mesh electrodes. After modification of the electrodes, the flow rate at a voltage of 6 V for purity water increases from 26.9 µL/min to 87.6 µL/min, and the limiting hydrostatic pressure improves from 59.3 Pa/V to 113.9 Pa/V. The polyaniline-wrapped platinum-coated titanium mesh electrodes can also keep undamaged surface morphology and unaltered redox performance after a long time EOP performance test, which can make it suitable for bubble-free uses in microfluidic system, drug delivery, and cooling of microelectronic devices.

The P-glycoprotein (Pgp) is a major transporter involved in multidrug resistance (MDR) of cancer cells leading to chemotherapy failure. In our previous study, we demonstrated that the amide derivatives of pyxinol are promising modulators against Pgp-mediated MDR in cancer. In the present study, we designed and synthesized novel pyxinol derivatives linked to amino acid residues. We evaluated MDR (paclitaxel (Ptx) resistance) reversal potency of forty pyxinol derivatives in KBV cells and analyzed their structure-activity relationships. Half of our derivatives sensitized KBV cells to Ptx at non-toxic concentrations, among which the pyxinol compound bearing a methionine residue (3c) exhibited the best activity in MDR reversal. Compound 3c was found to possess high selectivity toward Pgp and sensitize the KBV cells to Pgp substrates by blocking the efflux function of Pgp. This manifestation may be attributed to its high binding affinity with Pgp, as suggested by docking studies. Overall, the biological profile and ease of synthesizing these pyxinol derivatives render them promising lead compounds for further development for Pgp-mediated MDR.

Molecular recognition based on hydrogen bond interaction plays a significant role in supramolecular self-assembly. In this work, we successfully developed a class of novel frameworks containing a urea in the recognition site and a carboxylate anion in the guest unit. The self-recognition model based on the interaction between urea and carboxylate anion could induce the molecules to assemble into a highly organized form. The crystal structures showed that they assembled in highly ordered two-dimensional architectures. The optical properties showed that the position of carboxylate anion on the diphenylacetylene backbone had an obvious influence on optical properties. The self-recognition strategy is useful for the construction of highly ordered self-assembled architectures.

An octanuclear copper complex, [Cu8(L)10(OH)4Cl2·(DMF)2]·2DMF ( HL= 4-(2-bromophenyl)-2H-1,2,3-triazole) has been synthesized. Single crystal diffraction reveals that it crystallizes in the triclinic space group P − 1. The complex shows fluorescent quenching compared with the free ligand. The {Cu8} displays overall strong antiferromagnetic (AF) coupling via hydroxyl groups, κ2-N,N-trizaoles and κ3-N,N,N-trizaoles, and the complex exhibits AF ordering under low temperature with TN = 8.5 K.

A family of nonlinear optical materials that contain the halide, oxide, and oxyhalide polar units simultaneously in a single structure, namely ABi2 (IO3 )2 F5 (A=K (1), Rb (2), and Cs (3)), have been designed and synthesized. They crystallize in the same polar space group (P21 ) with a two-dimensional double-layered framework constructed by [BiF5 ]2- and [BiO2 F4 ]5- units connected to each other by four F atoms, in which two [IO3 ]- groups are linked to [BiO2 F4 ]5- unit on the same side. A hanging Bi-F bond of [BiF5 ]2- unit is located on the other side via ionic interaction with the layer-inserted alkali metal ions to form three-dimensional structure. The well-ordered alignments of these polar units lead to a very strong second-harmonic generation response of 12 (1), 9.5 (2), and 7.5 (3) times larger than that of potassium dihydrogen phosphate under 1064 nm laser radiation. All of them exhibited a wide energy bandgap over 3.75 eV, suggesting that they will have a high laser damage threshold.

A copper(II) complex chlorido-{1-carboxylic acid ethyl ester-4, 7-bis[1-(carboxylic acid ethyl ester) benzimidazole-2-yl-methyl]-1,4,7-triazacyclononane}copper(II) hexafluorophosphate ethanol solvate ([CuClL]·PF6·EtOH) was synthesized and crystallographically characterized {where L = 1-carboxylic acid ethyl ester-4,7-bis[1-(carboxylic acid ethyl ester) benzimidazole-2-yl-methyl]-1,4,7-triazacyclononane}. X-ray structure analysis shows that the copper(II) adopts a distorted square pyramidal coordination geometry. The activity of dismutation of superoxide () of the complex in riboflavin–methionine–nitroblue tetrazolium was studied. The result shows that the complex possesses a high superoxide dismutase (SOD) activity in comparison to some reported SOD mimics. Its redox behavior was studied by cyclic voltammetry with the aim of elucidating the reason that the complex reduces superoxide radicals.

Mono-cationic Ru(II)-complexes [Ru(L)X(CH3CN)2]⋅X 1∼4 (1, L = 2,6-bis(benzimidazol-2-yl) pyridine (L1), X = Cl; 2, L = L1, X = OTf; 3, L = 2-(N-benzyl-benzimidazole-2-yl)-6-(benzimidazole-2-yl)pyridine (L2), X = Cl; 4, L = 2,6-bis(N-benzyl-benzimidazole-2-yl)pyridine (L3), X = Cl) were prepared and fully characterized. The two acetonitrile ligands of each complex are coordinated to the metal center cis to each other. Complex 2 was also structurally characterized by X-ray crystallography. It was found that complexes 1∼4 can catalyze the acceptorless dehydrogenation of primary alcohols to corresponding carboxylic acids and H2 in the basic aqueous solution, and the reactivity follows the order 1 = 2 > 4 > 3. Furthermore, complexes 1 or 2 can efficiently catalyze the conversion of various primary alcohols to carboxylic acid in good yields (72%–98%) and high selectivity in an alcohol/CsOH system (1/1, mol/mol). Using an excess amount of alcohol to CsOH results in the formation of the carboxylic acid in higher yield (up to 100%, based on CsOH) and higher turnover numbers (TON ∼ 10000) accompanied by the H2 evolution. Complexes 1 and 2 can act as a new class of phosphine- and N-heterocycle carbene free Ru(II) complexes for efficient conversion of primary alcohols to carboxylic acids and H2 in a homogeneous system.

[Image: see text] Pyxinol, the main metabolite of 20S-protopanaxadiol in human liver, was chosen as a novel skeleton for the development of anti-inflammatory agents. Pyxinol derivatives modified at C-3, C-12, or C-25 and selected stereoisomers were designed, prepared, and investigated for in vitro anti-inflammatory activities. Structure–activity relationship (SAR), focused on skeleton, was analyzed based on their ability to inhibit lipopolysaccharide (LPS)-induced nitric oxide (NO) synthesis. The preliminary SAR results signified that the biological activity of the pyxinol derivatives is largely dependent on the R/S stereochemistry of pyxinol skeleton and the hydroxy at C-3 is a modifiable position. Among the tested compounds, the 3-oximinopyxinol (4a) exhibited the most potent NO-inhibitory activity and was even comparable to the steroid drug. Furthermore, compound 4a also significantly decreased LPS-induced TNF-α and IL-6 synthesis and iNOS and COX-2 expressions via the NF-κB pathway. This study proves that pyxinol is an interesting skeleton for anti-inflammatory drug discovery.

Qingke (Tibetan hulless barley) has long been cultivated and exposed to long-term and strong UV-B radiation on the Tibetan Plateau, which renders it an ideal species for elucidating novel UV-B responsive mechanisms in plants. Here we report a comprehensive metabolite profiling and metabolite-based genome-wide association study (mGWAS) using 196 diverse qingke and barley accessions. Our results demonstrated both constitutive and induced accumulation, and common genetic regulation, of metabolites from different branches of the phenylpropanoid pathway that are involved in UV-B protection. A total of 90 significant mGWAS loci for these metabolites were identified in barley-qingke differentiation regions, and a number of high-level metabolite trait alleles were found to be significantly enriched in qingke, suggesting co-selection of various phenylpropanoids. Upon dissecting the entire phenylpropanoid pathway, we identified some key determinants controlling natural variation of phenylpropanoid content, including three novel proteins, a flavone C-pentosyltransferase, a tyramine hydroxycinnamoyl acyltransferase, and a MYB transcription factor. Our study, furthermore, demonstrated co-selection of both constitutive and induced phenylpropanoids for UV-B protection in qingke.

Nanomedicines can generally only reach cancer cells at the edges of tumors, leaving most tumor cells in the central regions untreated. Previous studies showed that treatment with the vascular disrupting agent combretastatin-A4-phosphate (CA4P) can disrupt tumor vasculature, causing vascular shutdown and leading to massive necrosis in the tumor core. In this research, we explored the effect of co-administration of CA4P on the antitumor activity of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) in Walker 256 tumor-bearing rats. The iodine 131 isotope was used for tracing and biodistribution analysis of nab-paclitaxel uptake. Liquid chromatography coupled with tandem mass spectrometry was performed to detect the intratumoral concentration of paclitaxel. Magnetic resonance imaging (MRI) was used to evaluate the effect of tumor treatment. Biodistribution results demonstrated that the tumor accumulations of both nab-paclitaxel and paclitaxel in the 131I-nab-paclitaxel + CA4P group were much higher than those in the 131I-nab-paclitaxel group. Nab-paclitaxel in combination with CA4P inhibited tumor growth significantly more potently compared with the CA4P group, nab-paclitaxel group and PBS group. Our results demonstrate that co-administration of CA4P increased the intratumoral accumulation of nab-paclitaxel and improved its therapeutic effect compared with single treatments.

Crop plants always encounter multiple stresses in the natural environment. Here, the effects of the fungicide zinc thiazole (ZT) on propagation of Ralstonia solanacearum, a bacterial pathogen, were investigated in peanut seedlings under salt stress. Compared with water control, salt stress markedly reduced pathogen resistance in peanut seedlings. However, impaired pathogen resistance was alleviated by treatment with dimethylthiourea, a specific ROS scavenger, or ZT. Subsequently, salt stress or combined salt and pathogen treatment resulted in inhibition of photosynthesis, loss of chlorophyll and accumulation of thiobarbituric acid reactive substances, which could be reversed by ZT. In addition, ZT treatment suppressed the salt stress up-regulated Na+ content and Na+/K+ ratios in peanut roots. Furthermore, salt stress or combined salt and pathogen treatment impaired the activities of antioxidant (e.g. superoxide dismutase/SOD and catalase/CAT), and defense-related (e.g. phenylalanine ammonia lyase /PAL and polyphenol oxidase/PPO) enzymes, which could be rescued by addition of ZT. In contrast, only slight changes of SOD and CAT activities were observed in pathogen-infected seedlings. Similarly, activities of PAL and PPO were slightly modified by salt stress in peanut seedlings. These results suggest that the ZT-enhanced pathogen resistance can be partly attributed to the improvement of photosynthetic capacity and defense enzyme activities, and also the inhibition of Na+/K+ ratios, in this salt-stressed crop plant.

Two dicyanopyridine derivatived compounds (I) (C14H10N4) and (II) (C15H16N4) were synthesized with high yields from each reaction of benzylidene malononitrile with dichloride zinc directly in methanol or ethanol solvent . Both the compounds were characterized by NMR, IR, ESI, elemental analysis and single-crystal X-ray diffraction techniques. Investigation of intermolecular interaction via Hirshfeld surface analysis indicates that these close contacts are mainly ascribed to N H···N hydrogen bonding. Frontier molecular orbital and natural bond orbital (NBO) analysis shows that compound (I) and (II) possess a relatively higher kinetic stability. As a general type of catalyst, the reactive activity in the reaction of benzophenone-imine cyanosilylation was carried out to give a better performance with high yields of 80.0% and 86.0% for (I) and (II) respectively.

Vitamin K epoxide reductases (VKORs) constitute a major family of integral membrane thiol oxidoreductases. In humans, VKOR sustains blood coagulation and bone mineralization through the vitamin K cycle. Previous chemical models assumed that the catalysis of human VKOR (hVKOR) starts from a fully reduced active site. This state, however, constitutes only a minor cellular fraction (5.6%). Thus, the mechanism whereby hVKOR catalysis is carried out in the cellular environment remains largely unknown. Here we use quantitative mass spectrometry (MS) and electrophoretic mobility analyses to show that KO likely forms a covalent complex with a cysteine mutant mimicking hVKOR in a partially oxidized state. Trapping of this potential reaction intermediate suggests that the partially oxidized state is catalytically active in cells. To investigate this activity, we analyze the correlation between the cellular activity and the cellular cysteine status of hVKOR. We find that the partially oxidized hVKOR has considerably lower activity than hVKOR with a fully reduced active site. Although there are more partially oxidized hVKOR than fully reduced hVKOR in cells, these two reactive states contribute about equally to the overall hVKOR activity, and hVKOR catalysis can initiate from either of these states. Overall, the combination of MS quantification and biochemical analyses reveals the catalytic mechanism of this integral membrane enzyme in a cellular environment. Furthermore, these results implicate how hVKOR is inhibited by warfarin, one of the most commonly prescribed drugs.

Introduced a method of synthesizing hierarchical EU-1 zeolite with organosilanes as additive, and studied the influences of following different kinds of organosilanes on the synthesis of hierarchical EU-1 zeolite: γ-glycidoxy propyl trimethoxy silane (GPTMS), N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxyl silane (APAEDMS), and N-(β-aminoethyl)-γ-aminopropyl dimethoxyl (ethyoxyl) silane (TMPED). The hierarchical EU-1 samples were characterized by XRD, SEM, N2 adsorption, FT-IR and NH3-TPD to analyze the crystallinity, morphology, surface area, pore size distribution and acidity. The results showed that hierarchical EU-1 zeolites were successfully synthesized; organosilanes have great influence on crystal morphology of EU-1 zeolites; the exterior surface area of hierarchical EU-1 zeolite, which synthesized with organosilanes (APAEDMS) adding into synthesis system, increased by 62.1% and mesopore volume increased by 129.1% compared with conventional EU-1 zeolites, thus can reduce the diffusional restriction markedly in catalytic reaction. The catalytic performance of hierarchical EU-1 zeolites were evaluated in m-xylene isomerization on fixed bed reactor. The catalytic data showed that the isomerization activity PX/X of the hierarchical EU-1 zeolites reached around 24.09% in theoretical thermodynamic equilibrium from 23.83%, and the selectivity of C8 aromatic hydrocarbon increased from 75.16% to 84.87%. The conversion of p-xylene increased from 16.30% to 18.41%.

A neutral complex [Ni(L1)Cl2] (1) with trigonal bipyramidal geometry at Ni(II) was prepared by the reaction of NiCl2 with 2,6-bis(isopropylaminomethyl)pyridine (L1) in THF and then a mono-cationic complex [Ni(L1)Cl](BF4) (2) and di-cationic complex [Ni(L1)(CH3CN)3](BF4)2 (3) could be obtained by extracting one or two Cl− ions from 1 with one or two equivalents of AgBF4 in THF or acetonitrile, respectively. Similarly, a neutral complex Ni(L2)Cl2 (4) was formed by reaction of NiCl2 with 2,6-bis(diethylaminomethyl)pyridine (L2), and the experimental results indicate that Ni(II) of 4 adopts a slightly distorted square pyramidal geometry, which is different from that of 1. Although the reaction of 4 with one equivalent of AgBF4 resulted in a mono-cationic complex, [Ni(L2)Cl]BF4 (5), with Ni(II) in a slightly distorted square planar coordination geometry, an unexpected dinuclear Ni(II) complex [Ni(L2-H)(MeOH)F(μ-F)]2(BF4)2 (6) with two fluoride ligands bridging the two Ni(II) centers rather than a di-ca...

A new green chemical route was designed in this paper for the synthesis of high-silica EU-1 molecular sieve in TEAOH–SiO2–Al2O3–HMBr2–H2O system in which tetraethylammonium hydroxide (TEAOH) substituted for sodium hydroxide (NaOH) as an alkali source. The physicochemical properties of the synthesized samples characterized by such means as X-ray powder diffraction (XRD), electrophoresis apparatus, precise pH meter, scanning electron microscope, Fourier infrared spectrometer (FT-IR), thermo gravimetric analyzer (TG) and temperature programmed desorption (NH3-TPD). The research results showed that the SiO2/Al2O3 ratio of EU-1 molecular sieve could reach 706 with TEAOH as an alkali source. The SiO2/Al2O3 ratio of the product was improved greatly to 1046 with the template agent increasing. The new synthetic route has also significantly expanded the synthetic phase region. The absolute value of zeta potential of the TEAOH sol system was obviously higher than that of the NaOH sol system, indicating the thermodynamic stability of the former sol system was higher and better for the synthesis of pure high-silica EU-1 molecular sieve. The FT-IR spectra and TG/DTG diagrams of products indicated that TEA+ occluded in the final products could balance electronegative framework. The amount of strong, weak and the total acidity reduced with the increase of SiO2/Al2O3 ratio. The catalytic results of methanol-to-hydrocarbon demonstrated that the molecular sieve prepared by the new method has better catalytic performance.

Ocotillol-type sapogenins (OTS) are major ginsenoside metabolites in human hepatic tissue. In order to better utilize OTS and derivatives thereof as anti-inflammatory compounds, present study produced multiple novel 3-amino acid OTS derivatives and evaluated their anti-inflammatory activity in vitro. The nitric oxide (NO) inhibitory activity of these compounds was used for OTS structure-activity relationship (SAR) evaluations, revealing that both R/S stereochemistry at C-24 and the amino acid type at C-3 influence such NO inhibitory activity. This activity was highest for an N-Boc-protected neutral aliphatic amino acid derivative of 24R-OTS (5a), which performed better than even hydrocortisone sodium succinate in vitro. Compound 5a was also able to markedly suppress the LPS-induced upregulation of TNF-α, IL-6, iNOS, and COX-2 via the NF-κB and MAPK pathways. This suggests that OTS derivatives may be valuable anti-inflammatory compounds worthy of further preclinical evaluation.

With propeller-like shape, hexaphenylbenzene bromides display different recognition abilities for guest molecules in solid state. HBH can encapsulate CH2Cl2 or Et2O molecules selectively from different solvent systems. For DBH, the recognition pattern is dominated between themselves. In CH2Cl2/toluene/Et2O system, toluene molecule can be encapsulated selectively by MBH. In these supramolecular assemblies, bromine bonding plays an important role.

Two copper-containing compounds based on MoO42–, [Cu4(phen)4(μ2-OH)2(μ3-OH)2(H2O)2][MoO4]2·10H2O (1) and [Cu(phen)2Mo2O7(phen)]·8H2O (2) (phen = 1,10-phenanthroline), were hydrothermally synthesized. In the crystal lattices of 1 and 2, discrete octameric water cycles and 2D layer water clusters were observed. The cyclic water octamer clusters exist stably in the channels constructed by [Cu4(phen)4(OH)4(H2O)2]2+ and MoO42– by hydrogen bonds in 1 at low temperature and 2D layer water clusters are formed by (H2O)16 units in 2.

We have synthesized a series of fluorene-based fluorophores, in which a central fluorene core has been modified with different peripheral arylene vinylene substituents that are able to activate aggregation-induced emission (AIE) characteristics. 9,9-Dioctylfluorene doubly end-capped at the 2,7-positions with triphenylethene groups, such as 4-(2,2-diphenylvinyl)phenyl (F1-(2,2)-HTPE) and 4-(1,2-diphenylvinyl)phenyl (F1-(1,2)-HTPE) were synthesized and compared to the tetraphenylethene analogue (F1-TPE). Both F1-(2,2)-HTPE and F1-(1,2)-HTPE glow with a deep blue fluorescence in THF solution with emission maxima (λem) of 426 and 403 nm, respectively. The λem slightly red-shifts in the solid-state to 458 nm for F1-(2,2)-HTPE and 437 nm for F1-(1,2)-HTPE. The fluorescence quantum yields (oF) of F1-(2,2)-HTPE (oF=35.1 %) and F1-(1,2)-HTPE (oF=26.2%) were found to be higher in solution compared to the near quenching of F1-TPE (oF=0.1%). Consequently, this results in weaker AIE-stability of F1-(2,2)-HTPE (αAIE=1.5) and F1-(1,2)-HTPE (αAIE=1.9) compared to F1-TPE (αAIE=125), suggesting that four phenyl groups are necessary for efficient AIE-activity of these fluorene bridged arylene vinylene type materials. In addition, decreasing the steric hindrance around the arylene vinylene moiety by removal of a phenyl ring is another method to decrease the AIE characteristics, in a similar manner to the commonly known "phenyl-locking". Non-polar triphenylethenes are poorer AIE materials than their tetraphenylethene analogues. Replacing the hydrogen atom of F1-(2,2)-HTPE with a cyano group affords fluorene end-capped with 2,3,3-triphenylacrylonitrile (F1-TPAN), which boosts the AIE-effect to αAIE=90.5 and red-shifts the solid-state emission (λem=528 nm) with near quenching in THF solution (oF=0.12%). X-ray crystallographic analysis of F1-TPAN indicates that the introduction of cyano groups can not only diminish the intramolecular steric hindrance in comparison of F1-TPE, but also improve the molecular cohesion ability via multiple CH···N interactions.

Four new Zn(II) and Cu(II) coordinated polymers ([ZnL2N3]ClO4 (1), [Cu2L2(CH3CN)]Cl4 (2) [CuL](NO3)2 (3), [Cu(H2O)L](SO4) (4) L = 2-((4-phenyl-2H-1,2,3-triazol-2-yl)methyl) pyridine (ptmp)) have been reported. All the compounds have been characterized by IR spectrum, elemental analyses and X-ray crystallography diffraction. Single-crystal X-ray diffraction analyses show that one-dimensional polymers are formed in these four complexes. Chain-like structures are formed in complex 1, 2 and 3, which are connected by azide, chloride and nitrate anions, respectively. In complex 4, one-dimensional left-handed polymer is formed by a μ2-SO4 bridge. The fluorescent and electrochemical properties of these four complexes were investigated. It was found that these three Cu(II) complexes displayed a quenching of fluorescence, while Zn(II) complex exhibited a clear enhanced fluorescence.

Four cupric complexes (1–4) with a newly designed ligand – (fluorene-9,9-diyl)dipropanoic acid – were obtained under different pH conditions. These complexes exhibit pH-dependent supramolecular self-assembly morphologies as 0D, 1D and 2D architectures, among which 1D water channels are formed by a triple winding helical chain with opposite chiral configurations in 3.

An electronic tuning Nazarov-type cyclization protocol was proposed for the synthesis of polysubstituted-1-indanones from the readily available starting materials 1,4-enediones. AlCl3 was highlighted as the most efficient promoter for this reaction.

An axial substitution of the coordinated acetonitrile molecules in dinuclear Cu(I) compound, [Cu2(μ-PhPPy2)2(CH3CN)2](ClO4)2 (1) (PhPPy2 = bis(2-pyridyl)phenylphosphine) by various dicarboxylates (isophthalate, terephthalate and naphthalene-2,6-dicarboxylate) led to a class of new linear coordination polymers, {[Cu2(μ-PhPPy2)2](μ-1,3-C6H4(CO2)2)}∞ (2), {[Cu2(μ-PhPPy2)2](μ-1,4-C6H4(CO2)2)}∞ (3) and {[Cu2(μ-PhPPy2)2](μ-2,6-C12H6(CO2)2)}∞ (4). X-ray crystallographic studies reveals that all the polymers adopt almost linear structures, where the dicarboxylate groups connect dinuclear Cu(I) units as linkers. In 2 and 4, polymeric chains are parallel to each other. However the chains in 3 are arranged layer by layer, where polymeric chains are parallel in one layer, but chains in the neighboring layers are aligned with the angle (42°). The detailed structural analyses demonstrate that in solid state, the polymeric chains display different orientations which are controlled by interchain π–π and CH–π interactions. In solid state, all the coordination polymers are highly emissive at room temperature, which exhibit phosphorescence characteristics and are assigned as metal to ligand charge transfer.

Four dithia[3.3]metaparacyclophane-bridged dimetallic ruthenium acetylide complexes (1–4), in which the cyclophane units exhibit characteristic edge-to-face interactions between the top and bottom aromatic decks, have been designed, synthesized, and structurally characterized. X-ray diffraction analysis of 1–3 revealed that effective edge-to-face interactions exist in the solid state. IR spectroelectrochemical results suggest that the dithia[3.3]metaparacyclophane bridging ligands are redox-noninnocent. The UV/Vis/NIR spectra of 1+, 2+, 3+, and 4+ display characteristic band envelopes, and the deconvoluted multiple transitions have been assigned with the aid of DFT calculations to combinations of metal-to-ligand charge transfer (MLCT) and ligand-to-ligand charge transfer (LLCT) with appreciable contributions from transannular π–π transitions, especially for 3+ and 4+.

The metal complex-based carriers are emerging likely as a new type of gene-delivery systems prone to systematic structural alteration and chemical tailoring. In our work, the DNA affinity of metal complexes with polybenzimidazoles was found to be one of the determinants that can regulate expression of the transgenes. Here, the correlations between the DNA affinity and transfection efficacy were explored by characterizing gene-delivering properties of a series of Co(2+)- and Ca(2+)-polybenzimidazole complexes. The binding equilibrium constants (Kobs) of the divalent metal complexes to DNA, which is considered as a measure of the DNA affinity of metal complexes, were evaluated by isothermal titration calorimetry (ITC) and UV-visible absorption titration. The properties of DNA condensates formed with the metal complexes including sizes, ζ potential and morphology were observed to be altered with Kobs values. The monodispersed spherical condensates were found only for the Ca(2+) complexes whose DNA affinity is weaker than that of the Co(2+) complexes. However, the cell internalization examination indicated that cell uptake of the DNA condensates is independent of homogeneity in their sizes and morphology. The comparison of transgene expression showed that that the Ca(2+) complex-mediated transfection has higher efficiency than the Co(2+) complexes under the conditions tested, and the transfection efficacy cannot be correlated with the cell uptake of DNA condensates. Moreover, the Ca(2+) complexes and their DNA condensates had lower cytotoxicity than the Co(2+) complexes. Thus, the DNA affinity should be one of the factors to be capable of regulating the gene-delivering property of metal complexes.

Solvothermal reactions of hexakis(4-formylphenoxy)cyclotriphosphazene (H(6)L1) with Cd(NO(3))(2)·4H(2)O in H(2)O/DMF under different synthesis temperatures produced two new compounds, namely, {[Cd(3)(C(42)H(24)O(18)P(3)N(3)) (H(2)O)(7)]·xGuest}(n) (1), and {[Cd(2)(C(42)H(24)O(18)P(3)N(3)) (H(2)O)(2)]·xGuest}(n) (2). Compound 1 exhibits a novel 3D framework adopting 2,4,6-connected 3-nodal topology with the point (Schläfli) symbol {4(4)·6(2)}{4(5)·6(2)·8(8)}{4} constructed from the joint of neutral Cd(2) SBUs, mono-Cd ions and L1 ligands. Compound 2 reveals a 2D crystal structure exhibiting a 3,6-connected 2-nodal kgd topology with the point (Schläfli) symbol {4(3)}(2){4(6)·6(6)·8(3)} constructed from the connection of Cd centers and L1 ligands. In these two compounds, the ligands L1 are fully deprotonated, whose six extended carboxyl arms connect six different/same metallic nodes to form high dimensional frameworks. The variable reaction temperature must be responsible for the higher coordination number and versatile coordination modes of carboxylates in 1 compared to the ones in 2, resulting in the formation of a distinct crystal structure. In the solid state, both complexes are photoluminescent (LMCT) at room temperature.

The significant involvement of weak intermolecular interactions and steric and/or symmetry-related packing features was assessed with supramolecular arrays of 4-hydroxyphenyl amides in the crystal structure. The one-dimensional chain is observed in the aryl substituted 4-hydroxyphenyl amides, while alkyl analogs generate 2D or 3D arrays. A comparison of supramolecular assemblies in the similar 4-hydroxyphenyl amide compounds in the Cambridge Structural Database has been presented. It is correlated with the different steric constraints of aryl and alkyl groups to create chains, 2D sheets and 3D-interpenetrated networks in the asymmetric 4-hydroxyphenyl amides. A comprehensive analysis of crystal packing and energy features of the selected 4-hydroxyphenyl amide derivatives is reported.

We have demonstrated that the metal complexes of polybenzimidazoles are emerging likely as a new type of gene-delivery systems based on their strong DNA-condensing ability. However, the in vitro transfection efficacy of the DNA condensates formed with the metal complexes was relatively low. The positively charged peptides, such as cell-penetrating peptides and nuclear localization sequences (NLSs), have been reported to be capable of enhancing expression of the transgenes, likely as they promote entrance of their electrostatic complexes with DNA into the nuclear through nuclear pores. Here, we explored expression of the genes transferred by a series of Co(II) complexes in the presence of NLS (PKKKRKV) in normal and cancer cell lines. The results showed that the Co(II) complexes lead to the more pronounced DNA condensation in the presence of NLS than that in the absence of NLS. The binding of NLS prior to addition of the Co complexes can significantly reduce both the size and the population of the condensates at the given Co complexes/DNA ratios, compared with the NLS-free condensates. Meanwhile, the binding of NLS can considerably increase surface positive charges on the DNA nanoparticles. The suitable sizes and high surface positive charges facilitate the entrance of the nanoparticles into cells. Luciferase activity assay indicated that the transfection efficacy of the NLS-bound condensates was five-fold of that of the NLS-free ones in different cell lines, and comparable to that of the condensate formed with the commercially available carrier PEI. Moreover, cell viability assay of the NLS-bound condensates showed lower cytotoxicity than the NLS-free ones. Thus, the combination of NLS and cationic metal complexes might offer a new type of ternary delivery systems.

A highly diastereoselective and regioselective [2+2]-cycloaddition reaction of 3-ylideneoxindoles has been accomplished using visible light photocatalysis. This visible light photocatalytic protocol allows an expedient access to diversely functionalized and structurally constrained oxindole derivatives containing two spirocycles and four stereogenic centers, including two all-carbon quaternary centers.

Three dinuclear Mn(II) complexes, [Mn2(EGTB)(NO3)2(H2O)4](NO3)2 (1), [Mn2(EGTB)(NO3)4] (2) and [Mn2(EGTB)(NO3)(H2O)](NO3)3 (3) (EGTB = N,N,N′,N′-tetrakis(2′-benzimidazolylmethyl)-1,4-diethylene amino glycol ether) were prepared and characterized. Their crystal structures revealed a relationship between synthesis temperature and structure. With increasing the reaction temperature from 60 to 120 °C or 160 °C, the Mn–Mn distances are shortened from 14.019 A in 1, 7.662 A in 2 to 5.662 A in 3. Additionally, polyphenol oxidase (PPO) activity of those three complexes was studied by measuring the rate of increase in absorbance at 320 nm of pyrogallol substrate. At pH 7.8 and 30 °C, the turnover numbers are 5.58 h−1 for 1, 11.38 h−1 for 2 and 13.97 h−1 for 3, respectively. Furthermore, in pH 7.8–8.2, their catalytic activity increased with rising pH.

Three phenylethynes bearing methyl carboxylate (HL1), monocarboxylate (H(2)L2), and dicarboxylate (H(2)L3) groups were utilized as ligands to synthesize a new class of organometallic silver(I)-ethynide complexes as bifunctional building units to assemble silver(I)-organic networks. X-ray crystallographic studies revealed that in [Ag(2)(L1)(2)·AgNO(3)](∞) (1) (L1= 4-C(2)C(6)H(4)CO(2)CH(3)), one ethynide group interacts with three silver ions to form a complex unit. These units aggregate by sharing silver ions with the other three units to afford a silver column, which are further linked through argentophilic interaction to generate a two-demensional (2D) silver(I) network. In [Ag(2)(L2)·3AgNO(3)·H(2)O](∞) (2) (L2 = 4-CO(2)C(6)H(4)C(2)), the ethynide group coordinates to four silver ions to form a building unit (Ag(4)C(2)C(6)H(4)CO(2)), which interacts through silver(I)-carboxylate coordination bonds to generate a wave-like 2D network and is subsequently connected by nitrate anions as bridging ligands to afford a three-demensional (3D) network. In [Ag(3)(L3)·AgNO(3)](∞) (3) (L3 = 3,5-(CO(2))(2)C(6)H(3)C(2)), the building unit (Ag(4)C(2)C(6)H(3)(CO(2))(2)) aggregates to form a dimer [Ag(8)(L3)(2)] through argentophilic interaction. The dimeric units interact through silver(I)-carboxylate coordination bonds to directly generate a 3D network. The obtained results showed that as a building unit, silver(I)-ethynide complexes bearing carboxylate groups exhibit diverse binding modes, and an increase in the number of carboxylate groups in the silver(I)-ethynide complex unit leads to higher level architectures. In the solid state, all of the complexes (1, 2, and 3) are photoluminescent at room temperature.

Two new glycoluril derivatives, namely 6-phenyl-1,4-dioxo-2,2a,3,4,6,7-hexahydro-1H,5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-2a,7b-dicarboxylate (1), and diethyl 6-(2,4-dichorophenyl)-1,4-dioxo-2,2a,3,4,6,7-hexahydro-1H,5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-2a,7b-dicarboxylate (2) have been synthesized and structurally determined by X-ray diffraction analysis. Compound 1 is, monoclinic, space group C2/c, with a = 20.0784(7), b = 9.0316(3), c = 23.0980(8) A, β = 98.3930(10), V = 4143.7(2) A3, with Z = 8 for d calc = 1.338 Mg/m3. The analog 2 is, Triclinic, space group P-1, with a = 8.9353(18), b = 10.466(2), c = 14.679(3) A, β = 73.60(3), V = 1268.1(4) A3, with Z = 2 for d calc = 1.533 Mg/m3. X-ray analysis reveals that both glycoluril derivatives bearing two free syn-urea NH groups and two ureidyl C=O, assemble the same one-dimensional chains in the solid-state running parallel to the [110], [1–10] and [010] directions via N–H···O hydrogen bonds. Two new glycoluril derivatives, namely 6-phenyl-1,4-dioxo-2,2a,3,4,6,7-hexahydro-1H,5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-2a,7b-dicarboxylate (1), and diethyl 6-(2,4-dichorophenyl)-1,4-dioxo-2,2a,3,4,6,7-hexahydro-1H,5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-2a,7b-dicarboxylate (2), both bearing two free syn-urea NH groups and two ureidyl C=O, assemble the same one-dimensional chains in the solid-state running parallel to the [110], [1–10] and [010] directions via R 2 2 (8) N–H···O hydrogen bonds.

Two polymorphs of biphenyl-4,4'-diaminium bis(3-carboxy-4-hydroxybenzenesulfonate) dihydrate, C(12)H(14)N(2)(2+)·2C(7)H(5)O(6)S(-)·2H(2)O, have been obtained and crystallographically characterized. Polymorph (I) crystallizes in the space group P2(1)/c with Z' = 2 and polymorph (II) in the space group P-1 with Z' = 0.5. The benzidinium cation in (II) is located on a crystallographic inversion centre. In both (I) and (II), the sulfonic acid H atoms are transferred to the benzidine N atoms, forming dihydrated 1:2 molecular adducts (base-acid). In the crystal packings of (I) and (II), the component ions are linked into three-dimensional networks by combinations of X-H...O (X = O, N and C) hydrogen bonds. In addition, π-π interactions are observed in (I) between inversion-related benzene rings [centroid-centroid distances = 3.632 (2) and 3.627 (2) Å]. In order to simplify the complex three-dimensional networks in (I) and (II), we also give their rationalized topological analyses.

The conditions for the preparation of PbO2 modified Pt rotation disc electrode in solutions containing HC104 and Pb(II) were studied, and the morphology and composition of the obtained PbO2 film were characterized by SEM and XRD techniques, respectively. The results show that the modification process of PbO is dependent on the rotation velocity of the electrode and the concentrations of HCIO4 and Pb(II). And it was observed that the obtained PbO2 film was rutile β-PDO2 structure. At a certain positive potential, HO· and HO2· radicals can be generated on the surface of the modified PbO2/Pt electrode and then oxidize phenols. According to the change of the responding anodic current, the determination of phenols was realizable and good results were obtained.

A new coordination polymer, {[Na2Cu(Ac)4(H2O)]·H2O} n (HAc = acetic acid), has been synthesized and structurally characterized by IR spectroscopy and X-ray crystallography. The compound crystallizes in the orthorhombic system, space group Pccn with a = 16.9076(17) A, b = 11.8375(12) A, c = 15.7567(16) A, V = 3153.6(6) A3. Four oxygen atoms from different Ac− groups coordinate to the copper atom in a square-planar arrangement. Each sodium ion is in a distorted octahedral environment, being coordinated by one aqua ligand and five acetate oxygen atoms from two adjacent [Cu(Ac)4] units. An alternating arrangement of metal ions and bridging acetate ligands results in the formation of two-dimensional sheets which are further linked into a three-dimensional network by the water molecules between the layers through rich hydrogen bonds. The title compound {[Na2Cu(Ac)4(H2O)]·H2O} n (HAc = acetic acid) was synthesized and structurally characterized by X-ray crystallography. Four oxygen atoms from different Ac– groups coordinate to the copper atom in a square-planar arrangement. Each sodium ion is in a distorted octahedral environment, being coordinated by one aqua ligand and five acetate oxygen atoms from two adjacent [Cu(Ac)4] units. An alternating arrangement of metal ions and bridging acetate ligands results in the formation of two-dimensional sheets which are further linked into a three-dimensional network by the water molecules between the layers through rich hydrogen bonds.

A highly efficient synthesis of unsymmetrical 1,4-enediones from 1,3-dicarbonyl compounds and methyl ketones or terminal aryl alkenes has been developed via a focusing domino strategy. Simple and readily available starting materials, mild reaction conditions, and a very simple operation are advantages of the reaction, which allow straightforward synthesis of a variety of unsymmetrical 1,4-enediones.

Two new coordination polymers based on copper(I) halide clusters, [Cu2(2-mBIM)Cl2]n (1) and [Cu(2-mBIM)Br]n (2) [2-mBIM = bis(2-methylimidazo-1-yl)methane], have been synthesized from an in situ reduction reaction of CuX2 (X = Cl, Br) and ligand 2-mBIM under solvothermal conditions.

A novel mono-ionizable receptor 2 possessing three aminopyridyl and one carboxylic group in 1,3-alternate conformation based on thiacalix[4]arene, confirmed by single crystal X-ray analysis, was prepared. For competitive solvent extraction of alkali metal (Na+, K+ and Cs+) and some transition metal (Cu2+, Zn2+, TI+, Ag+) cations from aqueous solutions into chloroform, it was found that the introduction of proton-ionizable group (carboxylic acid moiety) into the aminopyridyl-thiacalix[4]arene derivative could further improve its Ag+ extractability with high selectivity.

Cocrystallization of imidazole or 4-methylimidazole with 2,2'-dithiodibenzoic acid from methanol solution yields the title 2:1 and 1:1 organic salts, 2C(3)H(5)N(2)(+).C(14)H(10)O(4)S(2)(2-), (I), and C(4)H(7)N(2)(+).C(14)H(10)O(4)S(2)(-), (II), respectively. Compound (I) crystallizes in the monoclinic C2/c space group with the mid-point of the S-S bond lying on a twofold axis. The component ions in (I) are linked by intermolecular N-H...O hydrogen bonds to form a two-dimensional network, which is further linked by C-H...O hydrogen bonds into a three-dimensional network. In contrast, by means of N-H...O, N-H...S and O-H...O hydrogen bonds, the component ions in (II) are linked into a tape and adjacent tapes are further linked by pi-pi, C-H...O and C-H...pi interactions, resulting in a three-dimensional network.

Single crystal X-ray structural characterizations are recorded for an array of adducts of the form {AgX:[dppc][PF 6 ]} n ( n = 1 or 2), [dppc][PF 6 ] = 1,1′-bis(diphenylphosphino)cobaltocenium hexafluorophosphate, X = Cl, Br, NO 3 , NO 2 , C 6 H 5 CO 2 , CF 3 CO 2 . Synthetic procedures for all adducts are reported. All compounds have been fully characterised by elemental analysis and spectroscopic techniques. The structures in the solid state were found to depend on the nature of the counterion, for X = NO 3 , NO 2 , the complex being monomeric {[dppc-P,P′]Ag(NO 3 ) 2 } or {[dppc-P,P′]Ag(NO 2 )}, for X = Cl, Br, C 6 H 5 CO 2 , CF 3 CO 2 , the complex is a dimer.

A new 1:2 inclusion complex of cucurbit[8]uril (CB[8]) and protonated N-phenylpiperazine was synthesized and characterized by 1H NMR and X-ray crystallography. The crystal structure showed that the phenyl rings of the two equivalents of guest encapsulated in the cavity of CB[8] are parallel to one another with a mean plane separation of 3.899 A. In contrast, the piperazinyl phenyl ammonium moieties slightly protrude from the ureidyl carbonyl lined portals in order to accommodate the ion–dipole interaction between host and guest which provides a substantial driving force for the assembly. The oxygen atoms of the carbonyl groups form hydrogen bonds with the hydrogen atoms in both bridging methylene groups of CB[8] and water molecules. There are also hydrogen bonds formed among CB[8], water, and the protonated piperazinyl rings. These hydrogen bonds are formed between the ureidyl C=O groups and hydrogens in methylenes of piperazinyl rings; through hydrogen bonding N+–H···O(H)–H···O=C. The protonated piperazinyl rings connect the carbonyl groups with the bridging water molecules.

Two dinuclear complexes [M2(EGTB)(NO3)2(DMF)2](NO3)2 · 2DMF (M = Cu, 1; Co, 2) were synthesized and structurally characterized, EGTB is N,N,N′,N′-tetrakis (2-benzimidazolylmethyl)-1,4-diethylene amino glycol ether, and DMF is dimethylformamide. The polyphenol oxidase (PPO) activities of 1 and 2 on pyrogallol oxidation have been investigated, showing that the rate constants k cat increase with increases of reaction temperatures and pH.

Single crystals of a new polymorph of 1,4-bis(imidazol-1-ylmethyl)benzene dihydrate (bix x 2H(2)O), C(14)H(14)N(4) x 2H(2)O, have been obtained by the hydrothermal method. The asymmetric unit is composed of two independent half-bix molecules, one on an inversion center and one on a twofold axial site, and two water molecules. The disordered water molecules link into discrete tetrameric water units via two O-H...O hydrogen bonds, forming planar R(4)(4)(8) rings. These tetrameric water units and bix molecules are further linked by two O-H...N hydrogen bonds into a three-dimensional network in which an R(20)(20)(106) hydrogen-bonded ring is observed. These large rings lead to the formation of a fivefold interpenetrated network. If both the tetrameric water units and the bix molecules can be regarded as connected nodes, one single three-dimensional net can then be rationalized as a CdSO(4) network. This study indicates that topological methodology can be applied in some cases in order to understand the inherent characteristics of some hydrogen-bonded supramolecular assemblies.

Three inorganic-organic hybrid frameworks [Mn(HIMDC)(4,4′-bipyo)0.5(H2O)]n(1), [Cd(H2IMDC)2(2,2′-bipyo)] (2) and [Ca(HIMDC)(H2O)2·H2O]n(3) (H3IMDC = 4,5-imidazoledicarboxylate; 4,4′-bipyo = 4,4′-bipyridine-N,N′-dioxide; 2,2′-bipyo= 2,2′-bipyridine-N,N′-dioxide) have been hydrothermally synthesized and characterized by the elemental analyses, IR spectra, TG analysis and the single crystal diffraction. Both compounds 1 and 3 exhibit 2D layers while 2 is a monomer. It is noteworthy that compound 2 exhibits strong fluorescent emission in the solid state at room temperature.

A series of 1,3-alternate conformation thiacalix[4]arenes containing different isomeric aminopyridyl pendent arms have been synthesized. It was found that their self-assembly behaviors and complexation properties strongly depended on the structures of aminopyridyl pendent arms. The crystal structures demonstrate that tetra(meta-aminopyridyl)-thiacalix[4]arene motif is capable of forming intramolecular hydrogen bondings between the sp2 nitrogen donors in the meta position of the aminopyridyl groups and the facing amide N–H of the adjacent aminopyridyl groups, and self-assembles via C–H⋯O weak hydrogen bondings and C–H⋯π interaction to generate a double stranded rectilineal networks. By contrast, in the case of tetra(para-aminopyridyl)-thiacalix[4]arene, the presence of para-aminopyridyl units enables the formation of N–H⋯N strong hydrogen bondings between the individual molecules leading to the solid-state structure with water-bridged double strands. Their complexation properties had been also studied by measurement of the stability constants for their complexation in a range of metal cations and investigation of their binding models via 1H NMR titration and ESI-MS experiments. It was found that the three ligands exhibited high and selective extractability toward Ag+, and their stoichiometry of ligand to Ag+ was 1:1, while the meta-aminopyridyl derivative showed the best extraction capacity and possessed the most efficient binding sites.

Four novel trinuclear copper(II)/nickel(II) complexes with four trianionic pentadentate ligands, N-(3-t-butylbenzoyl)-5-nitrosalicylhydrazide (H33-t-bbznshz), N-(3,5-dimethylbenzoyl)salicylhydrazide (H33,5-dmbzshz), N-(phenylacetyl)-5-bromosalicylhydrazide (H3pabshz) and N-(3-t-butylbenzoyl)salicylhydrazide (H33-t-bbzshz) have been synthesized and characterized by X-ray crystallography. These trinuclear compounds all have an M–N–N–M–N–N–M core formed by three metal ions and two ligands. The geometries of three Cu(II) ions in compound Cu3(3-t-bbznshz)2(H2O)(DMF)(py)2 · DMF (1) alternate between distorted square pyramidal and square planar, while in compound Cu3(3,5-dmbzshz)2(py)2 (2), they are all square planar. Three Ni(II) ions in compound Ni3(pabshz)2(DMF)2(py)2 (3) and Ni3(3-t-bbzshz)2(py)4 · 2H2O (4) follow square-planar/octahedral/square-planar coordination geometry. Compounds 1, 2 and 4 are bent trinuclear, with the bend angles of 156.4°, 141.49° and 127.1°, respectively, while the three nickel ions in compound 3 are strictly linear, with an angle of 180°. Studies on the trinuclear Ni(II) complexes show that the β-branched N-acylsalicylhydrazide ligands with sterically flexible Cα methylene groups are easier to yield linear trinuclear Ni(II) complexes, while α-branched N-acylsalicylhydrazides ligands tend to form bent trinuclear Ni(II) complexes. Antibacterial screening data indicate that the trinuclear Cu(II) compound 2 is more active than 1 and mononuclear Cu(II) compound, bent trinuclear Ni(II) compound 4 is more active than linear compound 3 and less active than tetranuclear nickel compound in the previous study.