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Supramolecular host–guest systems are generally at thermodynamic equilibrium states or in kinetically trapped states. Herein, we demonstrate the concept of a chemical fuel-driven competitive host–g... more...

In this work, sewage sludge flocculated with ferrous sulfate (SFS) was treated by one-step pyrolysis and ZnCl2 activation to obtain magnetic Fe-containing carbon, which was used to remove elemental mercury (Hg0) from flue gas. When 30% ZnCl2 was added to SFS (names as SFS-30), sulfides, chloride, magnetic FexOy, as well as a suitable BET surface area were produced during pyrolysis. SFS-30 showed a maximum mercury removal efficiency of 96.1%. The presence of O2 and a low SO2 concentration enhanced Hg0 removal, while H2O vapor and a high concentration of SO2 inhibited it. The addition of ZnCl2 increased the BET surface area as well as the conversion of sulfate to sulfide, which were both beneficial for Hg0 removal. In addition, the generated magnetism during the pyrolysis process assisted in the recovery and utilization of SFS-30 in flue gas. After being magnetically separated from a mixture with fly ash, spent SFS-30 was thermally regenerated and recycled. After 8 Hg0 capture and regeneration cycles, the removal efficiency was not notably degraded, demonstrating that SFS-30 prepared by one-step pyrolysis with ZnCl2 activation can be used for Hg0 removal. The results of this study have guiding significance for practical engineering applications of this material. more...

To realize the application of xylan based film in food and drug packaging, the poor mechanical property and film-forming property of xylan based film must be overcome. Herein, a good oxygen barrier composite film with desired mechanical properties was prepared based on carboxymethly xylan (CMX), chitosan (CS), and graphene oxide (GO). The results of scanning electron microscope revealed the composite film had a dense and continuous structure, which will endow the composite film with excellent mechanical property. As expected, the composite film with the 0.5% mass fraction of GO exhibited best mechanical property, among which the tensile stress, tensile strain, and Young's modulus of the composite film reached 50.81 MPa, 47.61%, and 1.39 GPa, respectively. The oxygen barrier properties of the composite films significantly increased with the addition of graphene oxide due to the dense, stacked multilayer structure. In addition, these composite films exhibited good antibacterial properties. Therefore, these films show great promise in the field of food packaging and wound dressing due to their excellent mechanical, oxygen barrier and antibacterial properties. more...

Rapid fabrication of organohydrogels at room temperature without external stimuli is a challenge. Inspired by plant catechol chemistry, a self-catalytic system established using sodium lignosulfonate and copper(II) ions (Ls–Cu2+) has been developed and applied to fabricate organohydrogels rapidly with fascinating multifunctional properties. The Ls–Cu2+ pair can induce ammonium persulfate (APS) to generate free radicals at room temperature, and subsequently initiate the free radical polymerization of hydroxyethyl acrylamide (HEAA) in water–glycerol binary phases in less than 30 s, without the removal of oxygen. The presence of the Ls–Cu2+ pair also endows the organohydrogel materials with fascinating UV-blocking (∼100%) and electrically conductive properties, and thereby they can be exploited as epidermal sensors. Owing to the presence of glycerol, the as-prepared organohydrogel exhibits intriguing anti-freezing (∼−50 °C) and anti-drying abilities (22–60 °C). This work taps the potential of dynamic plant catechol chemistry in the field of organohydrogel materials. more...

An amazing and stable carbonized octahedral frame material Cu-PC@OFM was synthesized and characterized through HRTEM, SEM, XRD, XPS, and Raman spectroscopy and nitrogen adsorption/desorption analysis. In particular, the carbon matrix carrier loaded with nano-copper not only maintains the original structure, but also the nano copper particles generated in situ significantly improve the catalytic performance and stability. It was disclosed that the copper-based catalyst material Cu-PC@OFM showed high catalytic activity in the borrowing hydrogen reaction and the synthesis of 1-benzyl-2-aryl-1H-benzo[d]imidazole derivatives with high yields in water. This copper catalytic system provided a much greener and efficient catalyst for the synthesis of functionalized amines and 1-benzyl-2-aryl-1H-benzo[d]imidazoles with good recovery performance in water, which was the first example for the Cu-PC@OFM material-catalyzed synthesis of 1-benzyl-2-aryl-1H-benzo[d]imidazoles. In addition, a plausible reaction mechanism was proposed through some condition control experiments, deuterium labeling experiments and separation of intermediates experiments. more...

In the process of solvothermal synthesis of one-dimensional (1D) Zn–Dy Schiff base coordination polymers, 25% of tetraoxolene anions (X2tetraox2−) underwent a one-electron reduction in situ reaction to form X2tetraox3˙− radical anions, which was confirmed by using the νCO vibration Raman spectra. Both the X2tetraox2− anion and the X2tetraox3˙− radical anion act as bridging ligands to connect two Zn–Dy Schiff base structural units, [DyZn(LSchiff)(NO3)(MeOH)]2+ (H2LSchiff = N,N′-bis(3-methoxysalicylidene)-1,3-diaminopropane) and [DyZn(LSchiff)(MeOH)2]3+, and finally assemble into two ionic zigzag chain-like coordination polymers, [Dy2Zn2(LSchiff)2(X2tetraox2−)1.5(X2tetraox3˙−)0.5(NO3)(MeOH)3](ClO4)0.5·2MeOH [1: X = Cl and 2: X = Br]. The two 1D Zn–Dy heterometallic coordination polymers exhibit the properties of single-molecule magnets (SMMs) and exhibit two-step magnetic relaxation behaviors under a dc field of 1500 Oe. Their effective energy barriers are adjusted by halogenated groups on the bridging ligands X2tetraox2− and X2tetraox3˙−. more...

Skin care biomaterials from natural compounds are increasingly needed in recent. We demonstrate a simple strategy to fabricate the dialdehyde xylan (DAX) crosslinked hydrogel with skin care potential. The hydrogel mainly consists of dialdehyde xylan, which is used as crosslinker for gelatin (G). Glycerol (Gly) and nicotinamide (NCA) are introduced here for improving the texture, antibacterial property as well as skin care functionality. The in vitro release results demonstrate that NCA can be released smoothly from the xylan-based gel, whereby the xylan-based fabricated gel can be utilized as an ideal matrix gel in skin care with loading and release function. The antibacterial ability is in the following order: Yeast > Bacillus subtilis > Staphylococcus aureus. The cytocompatibility experiments confirm the excellent viability of the gel. These merits demonstrate the fabricated hydrogel as a potential material in skin care. more...

Lithium-sulfur (Li-S) batteries have recently become a research hotspot because of their tempting theoretical capacity and energy density. Nevertheless, the notorious shuttle of polysulfides hinders the advancement of Li-S batteries. Herein, a two-dimensional covalent organic framework (COF) with extended π-conjugated units has been designed, synthesized, and used as sulfur recipients with 88.4 wt % in loading. The COF offers an elaborate platform for sufficient Li-S redox reactions with almost theoretical capacity release (1617 mA h g-1 at 0.1 C), satisfactory rate capability, and intensively traps polysulfides for a decent Coulombic efficiency (ca. 98.0%) and extremely low capacity decay (0.077% per cycle after 528 cycles at 0.5 C). The structural factors of the COF on the high-performance batteries are revealed by density functional theory calculations to be the high degrees of conjugation and proper interlayer space. This work not only demonstrates the great potential of COFs as highly efficient sulfur recipients but also provides a viable guidance for further design of COF materials to tackle shuttling issues toward active materials in electrochemical energy storage. more...

Improving the mechanical performance of hemicellulose-based hydrogel is an enormous challenge. Here, we propose a new strategy to achieve the hemicellulose-based hydrogels with superior mechanical performance through chain extension and semi-interpenetrating polymeric networks (semi-IPN). Xylan, known as the main type of hemicelluloses in angiosperms, is successfully modified to increase molecular weight by reductive amination reaction, overcoming the major limitation of brittleness. Then, the chemical network is obtained by graft copolymerizing acrylic acid (AA) with cross-linking agent N,N′-methylenebisacrylamide (MBA) in the presence of chain extended xylan (CEX). With the further introduction of ferric ions, a physical network is constructed via metal–ligand interactions. Such a xylan-based semi-IPN hydrogel shows excellent mechanical properties with a fracture tensile stress of 1.4 MPa, compression stress of 0.59 MPa, and the elongation at break of 1136%. In addition, the hydrogel also exhibits fine water absorbency (213.6 g/g) and high electrical conductivity (4.76 × 10–3 S/m). We anticipate that the resultant xylan-based semi-IPN hydrogels will open up a new approach for the design of high performance hemicellulose-based soft materials. more...

A heteropore covalent organic framework (COF) integrating tetraphenylethene skeleton and catechol segment is designed and synthesized. It exhibits extremely high stability in water under different pH conditions, which makes it an excellent material for adsorptive removal of Cd(II) from aqueous solutions with very fast adsorption kinetics, high uptake capacity, and good recyclability. more...

Three novel isostructural Zn2Ln2 cluster complexes with carbonate bridging ligands, {Zn2Ln2(μ3-CO3)2L2(acacF6)2}·CH3OH [H2L = N,N′-dimethyl-N,N′-(2-hydroxy-3-methoxy-5-methyl-benzyl)ethylenediamine; HacacF6 = hexafluoroacetylacetone; Ln = Dy, 1; Ln = Gd, 2; Ln = Eu, 3], have been prepared by fixing carbon dioxide in the atmosphere. Such carbonate bridging ligands may mediate ferromagnetic exchange between Ln3+ ions. The Zn2Dy2 compound (1) displays the properties of a single molecule magnet (SMM), showing slow magnetic relaxation at a 1500 Oe dc field, with an obviously larger Ueff/k value (83 K) with respect to the other carbonate-bridged Zn2Dy2 SMMs (≤34 K) and ZnDy dinuclear SMMs derived from the same ligand H2L used in this work (≤36.5 K), while the Zn2Gd2 compound (2) shows a moderate magnetocaloric effect and can be looked upon as a potential molecular material for low temperature magnetic refrigeration. more...

Oil-in-water food emulsions consisting of natural emulsifiers has been an active field of green scientific inquiry. Here, we extract two types of new hemicellulose-based emulsifiers (HH and HL) from holocellulose and dewaxed materials of bamboo (Phyllostachys pubescens), as well as compare their emulsifying soy oil ability, respectively. The main content of HH is arabinoxylan, while the primary composition in HL is glucan. The emulsifying capacity of these two types of hemicellulose-based emulsifiers are evaluated by droplet size distribution, surface charge and optical microscopy. Since HL possesses higher lignin and protein residual contents, the resultant emulsion exhibits smaller droplets and higher emulsion stability. In comparison, HH emulsifier has almost no emulsifying capacity due to the lack of non-polar groups. This study provides insight into the choice of hemicelluloses-based emulsifiers for the formation of stable oil-in-water food emulsions. more...

Under solvothermal conditions, five chiral 3d–4f wheel-like heterometallic hexanuclear clusters with the Schiff base ligand [H2L = N,N′-bis(3-methoxysalicylidene)-1,3-diaminopropane] were synthesized by the in situ ligand reaction of the 1,3-bis(2-pyridyl)-1,3-propanedione and generated the pyridine-2-carboxylate (PyCO2−) that acted as a bridging ligand; a peroxide anion formed by the spontaneous reduction of dioxygen plays a key role in the assembly of these complexes. The five isomeric 3d–4f heterometallic complexes, with molecular formula [M3Ln3(O2)L3(PyCO2)3](OH)2(ClO4)2·8H2O (M = Zn, Cu; Ln = Dy, Tb, Gd) represent the first anion-orientated chiral heterometallic cluster complexes composed of achiral components. Except for complex 1, we randomly measured the crystal structure of one of the two chiral enantiomers of complexes 2–5. Magnetic measurements show that the Zn3Gd3 complex exhibits a moderate magnetocaloric effect. The Cu3Tb3 complex is a single-molecule magnet (SMM) with an energy barrier (Ueff/k) value of 31.7(0.3) K under zero dc field, which is a larger value for Cu–Tb SMMs; the other three compounds Zn3Dy3, Zn3Tb3, and Cu3Dy3 exhibit field-induced magnetic relaxation. The Ueff/k value of Zn3Dy3 [>100 K, Hdc = 1000 Oe] is obviously larger than those of equilateral triangular Dy3 complexes (≤62 K). more...

Based on iminopyridine ligands (L1–L3), Fe(II) (Fe1–Fe3) and Co(II) (Co1–Co3) complexes were synthesized and characterized well. According to single-crystal XRD studies, Co3 exhibits a dimeric structure with a four-coordinated metal center. Whereas, the iron complexes (Fe1 and Fe3) coordinate with two ligands to form a distorted-octahedral and distorted-trigonal bipyramidal geometry, respectively. All these catalysts were tested for the polymerization of isoprene. Using MAO as the co-catalyst, the Fe3 catalyst containing a bulky substituent can provide trans-1,4-unit (64%) polyisoprenes, while the Fe1 catalyst afforded trans-1,4-unit polyisoprenes (32%). Conversely, the combination of EASC as the co-catalyst with Fe1–Fe3 catalysts can give 1,4-unit polyisoprenes with high trans-1,4-unit selectivity (up to 88%). The central metal atom of the catalysts plays a crucial role in isoprene polymerization and significantly affects their activity. Fe(II) catalysts showed the highest activity (up to 99% yield), and afforded polyisoprenes with high molecular weights (191 kg mol−1). However, Co(II) systems exhibited lower activity (60% yield) and the obtained polyisoprenes were of lower molecular weights (2.15 kg mol−1) with broad molecular weight distribution. more...

One-pot template construction of α,α′-bis(arylimino)-2,3:5,6-bis(pentamethylene)pyridyl iron chlorides achieved by reacting α,α′-dioxo-2,3:5,6-bis(pentamethylene)pyridine and the corresponding anilines along with the respective iron chloride in acetic acid provided yields of 26–76%. All these complexes were characterized by FT-IR, elemental analysis, 1H NMR, and X-ray diffraction analysis. Distorted-square-pyramidal geometries are observed in the molecular structures of Fe1 and Fe6, respectively. When MAO or MMAO is used as a cocatalyst, Fe1–Fe5 display a high activity of 107 g with highly linear, low-molecular-weight, and narrow-polydispersity polyethylenes (PEs) being obtained by ethylene polymerization. The catalytic activity of Fe1 reached a maximum activity ((3.81–3.93) × 107 g of PE (mol of Fe)−1 h–1) by using the cocatalyst MAO or MMAO at Al/Fe ratio of 5000. All of the synthesized iron precatalysts Fe1–Fe8 containing sterically ortho benzhydryl and aryl (2,4,6-substituents of the aryl ring) groups... more...

The ortho-benzhydryl-substituted α,α′-bis(arylimino)-2,3:5,6-bis(pentamethylene)pyridine-chromium(III) chlorides, [2,3:5,6-{C4H8C(N(2-R1-4-R2-6-(CHPh2)C6H2)}2C5HN]CrCl3 [R1 = R2 = Me Cr1, R1 = Me, R2 = CHPh2 Cr2, R1 = Et, R2 = CHPh2 Cr3, R1 = i-Pr, R2 = CHPh2 Cr4, R1 = Cl, R2 = CHPh2 Cr5, R1 = F, R2 = CHPh2 Cr6], differing in the electronic and/or steric properties of their aryl-R1 and -R2 groups, have been prepared by a one-pot template approach involving α,α′-dioxo-2,3:5,6-bis(pentamethylene)pyridine, the corresponding aniline and CrCl3(THF)3 in acetic acid. The molecular structure of six-coordinate Cr1 reveals the carbocyclic-fused N,N,N-ligand to adopt a mer configuration with the puckered sections of the two fused rings arranged mutually cis. On activation with MAO or MMAO, Cr1 - Cr6 displayed high activities (up to 1.83 × 106 g (PE) mol−1 (Cr) h−1) for the polymerization of ethylene with the MAO-promoted polymerizations in most cases more productive than with MMAO. In general, the chromium complexes appended with ortho-halide substituents (Cr6 (F)) and (Cr5 (Cl)), proved the most active with the overall order being: Cr6 > Cr5 > Cr1 > Cr2 > Cr3 > Cr4. All catalysts formed linear polyethylene displaying a wide range of molecular weights (from 2.17 to 300.4 kg mol−1) that were highly dependent on the nature of the ortho-R1 substituent with fluoride Cr6 forming the lowest molecular weight and the most sterically demanding Cr4 (i-Pr) the highest. more...

Orchestrating conflicting polymerization mechanisms in a single polymerization process through one external stimulus is a prerequisite to achieve in-situ selective synthesis of different monomers. Here we report an electrochemically controlled mechanism transformation that enables selective activation of living cationic or radical polymerization via an alternating voltage and dual electrocatalysts. Using identical mixed-monomer condition, a variety of desired block copolymer structures, including diblock, multiblock, random, and tapered copolymers can be obtained by simply varying the periods or phases of the alternating potential. Moreover, merging this electro-interconverted polymerization with a flow-chemistry technique can streamline preparation of functional polymer materials with complex multiblock structure. This study would offer a new vision on large-scale electrochemical synthesis of sequence-defined polymers. more...

Six types of 2,8-bis(imino)-7,7-dimethyl-5,6-dihydroquinoline, 2-(ArN[double bond, length as m-dash]CMe)-8-(ArN)-7,7-Me2C9H6N (Ar = 2,6-Me2C6H3L1, 2,6-Et2C6H3L2, 2,6-iPr2C6H3L3, 2,4,6-Me3C6H2L4, 2,6-Et2-4-MeC6H2L5, 2,4,6-tBu3C6H3L6), distinguishable by their steric and electronic profile, are described that can readily undergo complexation with cobaltous chloride to form their corresponding LCoCl2 chelates, Co1-Co6. The molecular structures of Co2 and Co3 reveal square pyramidal geometries with ring puckering a feature of the gem-dimethyl section of their unsymmetrical N,N,N'-ligands. On activation with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all the cobalt complexes exhibited exceptionally high activities for ethylene polymerization with levels reaching up to 1.19 × 107 g PE per mol (Co) per h for mesityl-containing Co4. Significantly, these catalysts exhibited good thermal stability by displaying their optimal performance at temperatures up to 70 °C whilst also maintaining appreciable catalytic lifetimes. With the exception of that obtained using the most sterically hindered Co6 (2,4,6-t-butyl), the polyethylenes are of low molecular weight (Mw≤16.0 kg mol-1) and of narrow dispersity (Mw/Mn≤3.4). Moreover, end-group analysis of these highly linear polymer waxes reveals evidence for unsaturated as well as various levels of fully saturated materials highlighting the role of both β-H elimination and chain transfer to aluminum as termination pathways. more...

Herein, a series of dialkylaluminum 2-substituted 6,6-dimethylcyclopentyl pyridin-7-oxylates Al1-Al7 were synthesized and characterized by 1H- and 13C-NMR spectroscopy and elemental analysis. The molecular structure of Al3 was proven to be a dimer of an aluminum complex. These aluminum complexes could efficiently initiate the ring-opening polymerization (ROP) of e-caprolactone (CL), and the structural differentiations of the resultant PCL were strongly dependent on the amount of BnOH (PhCH2OH) used. In the absence of BnOH, the resultant PCL showed a cyclic structure, whereas BnO-capped linear PCL was obtained in the presence of >2.0 equivalents of BnOH; the resultant PCL was a mixture of linear and cyclic PCLs in the presence of 1.0 equivalent of BnOH. Moreover, these aluminum complexes exhibited high efficiency towards the ROP of l-lactide (LLA); however, the activities were lower than those for the ROP of e-CL. Without BnOH, the resultant PLLA showed a highly linear structure with the alkyl-end group from aluminum complexes; on the other hand, PLLA displayed a major cyclic structure and minor BnO-capped linear PLLA if 1.0 equivalent of BnOH was employed, and the percentage of BnO-capped linear PLLA was increased by increasing the amount of BnOH. more...

The design of structurally dynamic molecular networks can offer strategies for fabricating stimuli-responsive adaptive materials. Herein we first report a gas-responsive dynamic gel system based on frustrated Lewis pair (FLP) chemistry. Two trefoil-like molecules with bulky triphenylborane and triphenylphosphine groups are synthesized as complementary Lewis acid and base with trivalent sites. They can together bind CO2 gas molecules and further form a cross-linked network via the bonding interactions between FLPs and CO2 . Such CO2 -bridged dative linkages are shown to be dynamic covalent bonds, which endow the frustrated Lewis network with adaptable behaviors and unprecedented gas-regulated viscoelastic, mechanical, and self-healing performance. This study is an initial attempt to apply the FLP concept in materials chemistry, but we believe that this strategy will open a promising future for gas-sensitive smart materials. more...

Electronically and sterically enhanced Fe (II) chloride complexes (Fe1 Fe6) bearing 2-(1-(2,6-dibenzhydryl-4-nitrophenylimino)ethyl)-6-(1-(arylimino)ethyl)pyridine (aryl = 2,6-Me2Ph L1, 2,6-Et2Ph L2, 2,6-iPr2Ph L3, 2,4,6-Me3Ph L4 and 2,6-Et2-4-MePh L5) and 2,6-bis(1-(2,6-dibenzhydryl-4-nitrophenylimino)ethyl)pyridine (L6) ligands have been prepared. In addition to the elemental and spectroscopic analysis of all new compounds; the molecular structures of Fe1, Fe2 and Fe6 have been subject of the X-ray diffraction. The catalytic potential of all the complexes was investigated for ethylene polymerization and compared with the results of prototypal precatalyst, 2,6-bis(1-(2,6-diisopropylphenylimino)ethyl)pyridyliron chloride (Fe0). On treatment with MAO and MMAO co-catalysts, Fe6 was essentially inactive, while the iron complexes (Fe1 Fe5) displayed exceptionally high activities as high as 2.53 × 107 gPE (mol of Fe)−1 h−1 at 50 °C and 3.86 × 106 gPE (mol of Fe)−1 h−1 at 100 °C, and afforded high molecular weight polyethylene up to 610.6 kg/mol. By comparing with catalytic performance of the reported bis(imino)pyridine-iron precatalysts bearing non-nitro para-substituents (CH3, Cl) including Fe0, these values of activity and molecular weight are found to be the highest reported up to date. Additionally, the resultant polyethylenes are characteristically linear as being confirmed by DSC (Tm = 125.3–135.6 °C) and high-temperature 13C NMR measurments. more...

The 8-(arylimino)-5,6,7-trihydroquinoline-nickel(II) chlorides, [8-N{2,6-R2-4-(C15H13)C6H2}C9H8N]NiCl2 (R = Me Ni1, Et Ni2, i-Pr Ni3, F Ni4, Cl Ni5), each appended with a remote para-dibenzocycloheptyl group, have been synthesized from either the pre-formed ligand (Ni1–Ni3) or by generating the ligand in-situ during complexation (Ni4, Ni5). The molecular structures of Ni2 and Ni3 adopt dimeric or trimeric forms in the solid state, in which the chlorides can act as doubly or triply bridging ligands. On treatment with either MMAO or Et2AlCl, Ni1–Ni5 showed low (Ni4, Ni5) to high activities (Ni1–Ni3: up to 4.58 × 106 g PE mol−1 (Ni) h−1) for ethylene polymerization producing unsaturated polyethylenes of low molecular weight (1.4–2.7 kg·mol−1) and narrow dispersity ( CH CH ) with respect to terminal vinyls ( CH CH2). The ortho-substituents of the precatalyst were found to not only affect the catalytic activity but also the vinylene:vinyl ratio and the branching content. Notably, the materials generated using ortho-fluoro Ni4/Et2AlCl possessed the least number of branches and an increased vinyl contribution. Furthermore, these unsaturated polyethylenes can be readily functionalized by epoxidation with almost quantitative conversion. more...

Two novel 3D pure inorganic compounds based on [Cr2Dy4(μ4-O)2(μ3-OH)4]10+ cluster units and sulfate anions are presented. Both complexes exhibit single-molecule-magnet (SMM)-like behavior. Permutation of the magnetic moment direction among SMM-like cluster units has a significant effect on the performance of molecular nanomagnets, and directional consistency shows obvious advantages. more...

Juglans mandshurica is a fast growing hard species, which is a tree in family of Juglandaceae and has a wide distribution in China, Korea and eastern Russia. Plant materials from J. mandshurica have extensively been used in folk medicines to prevent or cure gastric, esophageal, lung and cardiac cancer. As one chain of our searching for anticomplementary agents from natural sources, two epimeric ellagitannins, [2,3-O-4,4′,5,5′,6,6′,-hexahydroxydiphenoyl (HHDP))-(α,β)-D-glucose] (I) and pedunculagin (II) were purified from 70% acetone extracts of the stem barks of J. mandshurica by Thin Layer Chromatography and Sephadex LH-20 column chromatography approaches. The chemical structures of the isolated compounds were characterized by MS, NMR, and a careful comparation with published literatures. The epimeric ellagitannins I and II exhibited inhibitory properties against a classical pathway of complementary system with 50 % inhibitory concentrations (IC50) values of 65.3 and 47.7 μM, respectively, comparing with riliroside (IC50=104 μM) and rosmarinic acid (IC50=182 μM), which were used as positive controls. Thus, the work indicated both the two secondary metabolites possess excellent inhibitory activity and might be developed as potential anticomplementary chemicals. more...

Five distinct α,α′-bis(arylimino)-2,3:5,6-bis(hexamethylene)pyridine-cobalt(II) chloride complexes, [2,3:5,6-{C5H10C(NAr)}2C5HN]CoCl2 (Ar = 2,6-Me2C6H3, Co1; 2,6-Et2C6H3, Co2; 2,6-i-Pr2C6H3, Co3; 2,4,6-Me3C6H2, Co4; 2,6-Et2-4-MeC6H2, Co5), have been synthesized by one-pot template reaction of α,α′-dioxo-2,3:5,6-bis(hexamethylene)pyridine with the corresponding aniline and cobalt(II) chloride in acetic acid. The molecular structures of Co2 and Co3 reveal distorted square pyramidal geometries with two conformationally flexible eight-membered rings, a feature of the ligand manifold. On activation with either methylaluminoxane (MAO) or modified MAO (MMAO), all five complexes displayed high catalytic activities for ethylene polymerization (up to 3.62 × 106 g PE mol–1 (Co) h–1) generating strictly linear polyethylenes with the activity decreasing in the orders: Co4 > Co5 > Co1 > Co2 > Co3 (MAO) and Co1 > Co4 > Co2 > Co5 > Co3 (MMAO). Moreover, the nature of the aluminoxane cocatalyst employed had a marked effec... more...

Traditional preparation methods of the hydrogel are not only tedious but also requiring external stimuli. Here, a plant catechol-inspired self-catalytic system (sulfonated lignin and iron ion) has been introduced to rapidly trigger the graft polymerization of vinyl monomers on the carboxymethyl xylan (CMX) at room temperature, generating an elastic, UV-shield, and conductive hydrogel. The rapid preparation process can be finished at room temperature in 5 min without the removal of oxygen. The hydrogel shows charming extension ratio (up to 460%) and tensile stress (up to 23 kPa), which can be ascribed to the double network structure constructed from Fe3+ and CMX. The hydrogel exhibits great transparency (up to 85.37%), fascinating UV-blocking (up to 99%), and conductive features, thereby serving as potential human body sensors. The rapid preparation of xylan-derived hydrogels via dynamic lignin catechol chemistry may open up a new approach to high-valued utilization of biomass. more...

Energy dissipation underlies dynamic behaviors of the life system. This principle of biology is explicit, but its in vitro mimic is very challenging. Here we use an energy-dissipative self-assembly pathway to create a life-like polymer micellar system that can do periodic and self-adaptive pulsating motion fueled by cell energy currency, adenosine triphosphate (ATP). Such a micelle expansion-contraction behavior relies on transient supramolecular interactions between the micelle and ATP fuel. The micelles capturing ATPs will deviate away from the thermodynamic equilibrium state, driving a continuous micellar expansion that temporarily breaks the amphiphilic balance, until a competing ATP hydrolysis consumes energy to result in an opposing micellar contraction. As long as ATP energy is supplied to keep the system in out-of-equilibrium, this reciprocating process can be sustained, and the ATP level can orchestrate the rhythm and amplitude of nanoparticulate pulsation. The man-made assemblies provide a model for imitating biologically time-dependent self-assembly and periodic nanocarriers for programmed drug delivery. more...

Background:: Icariin (ICA), one of the main effective components isolated from the traditional Chinese herb Epimedium brevicornu Maxim., has been reported to possess extensive pharmacological actions, including enhanced sexual function, immune regulation, anti-inflammation, and antiosteoporosis. Methods:: Our study was designed to investigate the effect of ICA on cell proliferation and differentiation and the molecular mechanism of OPG/RANKL mediated by the Estrogen Receptor (ER) in hFOB1.19 human osteoblast cells. Results:: The experimental results show that ICA can stimulate cell proliferation and increase the activity of Alkaline Phosphatase (ALP), Osteocalcin (BGP) and I Collagen (Col I) and a number of calcified nodules. Furthermore, the mRNA and protein expression of OPG and RANKL and the OPG/ RANKL mRNA and protein expression ratios were upregulated by ICA. The above-mentioned results indicated that the optimal concentration of ICA for stimulating osteogenesis was 50ng/mL. Subsequent mechanistic studies comparing 50ng/mL ICA with an estrogen receptor antagonist demonstrated that the effect of the upregulated expression is connected with the estrogen receptor. In conclusion, ICA can regulate bone formation by promoting cell proliferation and differentiation and upregulating the OPG/RANKL expression ratio by the ER in hFOB1.19 human osteoblast cells. more...

A series of 8-(arylimino)-5,6,7-trihydroquinolines ligand pendant fluorenyl group at N-aryl ring, and their nickel complexes (Ni1 − Ni5) have been prepared and characterized. Once activated with Et2AlCl, the complexes Ni1, Ni2, and Ni3 bearing ligands from para-fluorenylaniline produced unimodal polyethylenes; on the contrary complexes Ni4 and Ni5 gave bimodal polyethylenes due to steric influence of ligands from ortho-fluorenyl anilines. With a increment of Et2Zn/Ni4 ratio from 0 to 400, the distinct bimodel polyethylenes were obtained with molecular weights shifted from 14.3 to 57.6 kg·mol−1; apart shiftment to higher molecular weights, the portion of low molecular weight decreased along with higher portion of high molecular weight. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1910–1919 more...

A series of 2-(1-(2,4-dibenzhydrylnaphthylimino) ethyl)6-(1-(arylimino) ethyl) pyridyliron(II) complexes (Fe1-Fe5) was synthesized and characterized. The molecular structure of the representative Fe2 was determined by single-crystal X-ray diffraction, revealing a distorted pseudo-square-pyramidal geometry around the iron center. On activation with eithermethyl aluminoxane (MAO) or modified methylaluminoxane (MMAO), all these iron complex precatalysts performed with high activities (up to 1.58 x 10(7) g (PE) mol(-1) (Fe) h(-1)) toward ethylene polymerization, producing highly linear polyethylenes with highmolecular weight and bimodal distribution, which was in accordance with high temperature C-13 NMR, high T-m values (T-m similar to 130 degrees C) and the GPC curves of the obtained polyethylenes. Meanwhile, DFT calculation results also showed the good correlation between net charges on iron and experimental activities. Compared with previous bis(imino) pyridyliron analogues, the current iron complexes containing the benzhydrylnaphthyl groups exhibited relatively higher activities and better thermalstability at elevated temperatures, especially at 80 degrees C as the industrial operating temperature, and still showed high activities toward ethylene polymerization up to 8.57 x 10(6) g (PE) mol(-1) (Fe) h(-1) in the presence of co-catalyst MMAO. In addition, these iron complex precatalysts all exhibited long lifetimes. (C) 2017 Wiley Periodicals, Inc. more...

Intelligent regulation of fluid mechanical properties is an enormous challenge. Here we report a photocontrolled thermogelling system that features switchable sol–gel transition in response to light. Such a system is composed of an amphiphilic copolymer appending with charged long alkyl stickers and α-cyclodextrin (α-CD) host units. Temperature can induce reversible threading/dethreading between the α-CD and the alkyl chain, leading to a sol–gel transition. With the introduction of a competitive photoresponsive azobenzene guest, one can remotely modulate the systemic gelation points in a broad temperature window via light irradiation. This class of responsive hydrogel systems would open up a new host–guest approach for the design of logical soft materials. more...

2-Chloro/phenyl-7-arylimino-6,6-dimethylcyclopenta[b]pyridylnickel chlorides (Ni1–Ni8) were synthesized from the respective ligands L1–L8 and characterized. Upon activation with either methylaluminoxane (MAO) or ethylaluminium sesquichloride (EASC), they show high catalytic activity of up to 10.84 × 106 g(oligomer) mol− 1(Ni) h− 1 in ethylene oligomerization. The products range from butenes to dodecenes for Ni1–Ni4, but are limited to butenes and hexenes in the case of Ni5–Ni8. DFT calculations indicate that the Ni C bond length in the model alkyl complexes depends both on the nature of the substituents at the heterocycles and the kind of the alkyl group, shedding some light on the preferences of the precatalysts toward oligomers or polyethylene. more...

Cycloocta[b]pyridin-10-one was prepared to form the corresponding imino derivatives, which then reacted with (DME)NiBr2 to form 10-aryliminocycloocta[b]pyridylnickel bromides (Ni1–Ni5). The new compounds were characterized by means of FT-IR spectroscopy as well as elemental analysis and the organic ligands were also analyzed by the NMR measurements. Furthermore, the molecular structure of a representative complex Ni3 was determined by the single crystal X-ray diffraction, indicating the distorted tetrahedral geometry around the nickel atom. Upon the activation with either methylaluminoxane (MAO) or diethylaluminium chloride (Et2AlCl), the title nickel complexes exhibited high activity in ethylene polymerization and produced polyethylene of low molecular weight (1.43–6.78 kg mol−1) and low dispersity (1.7–2.4), which suggests a single-site catalytic system. More importantly, the microstructure of the resultant polyethylene (especially degree of branching) and certain physical properties, such as Tm values, can easily be modulated by selecting the proper substituents within the ligands and adjusting the polymerization conditions. This finding demonstrates that it is plausible to use a single catalyst for synthesizing different types of polyethylene on demand.10-Aryliminocycloocta[b]pyridylnickel bromides (Ni1–Ni5), upon activation with either MAO or Et2AlCl, exhibited high activity towards ethylene polymerization and produced polyethylenes with low molecular weight (1.43–6.78 kg mol−1) and low dispersity (1.7–2.4). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 more...

A series of dinuclear chloroneodymium quinolinylcarboxylate compounds was synthesized and characterized. The nature and importance of metal-organic aggregations have been considered as an important factor regarding the molecular structure and catalytic performance. The neodymium center in all the title compounds exhibits the coordination numbers of 8. Cage aggregation was observed in the solid state, and the cyclic arrangement was achieved when water molecules were incorporated into the structure. Upon the activation with Al(i-Bu)3, all the title neodymium compounds form the efficient catalysts for isoprene polymerization. The catalytic activities are not strongly affected by the molecular aggregation of the precatalysts in the solid state, which indicates that the dissociation into mononuclear species takes place in the homogeneous medium. The resultant polyisoprenes exhibit high contents of the cis-1,4 fraction and high molecular weight. more...

Solid state emissive materials with high quantum yields and tunable emissions are desirable for various applications. A new TPE derivative (1) with two carbazole moieties and two cyano groups is reported, which shows typical aggregation induced emission behavior. Four crystals 1a, 1b, 1c, and 1d are obtained after crystallization from N,N-dimethylformamid (DMF), trichloromethane (CHCl3 ), tetrahydrofuran (THF), and dichloromethane (CH2 Cl2 ), respectively. Crystal structural analyses reveal that (i) molecules of 1 co-crystallize with DMF, CHCl3 , THF, and CH2 Cl2 in 1a, 1b, 1c, and 1d, respectively, and (ii) conformations of 1 are different within 1a, 1b, 1c, and 1d, and compound 1 within crystal 1a adopts the most twisting conformation. Crystalline solids 1a, 1b, 1c, and 1d exhibit high emission quantum yields up to 0.65, but their emission colors are varied from blue to green. In comparison, the amorphous solid of 1 is yellow-emissive with emission maximum at 542 nm. Moreover, the blue- or green-emissive crystalline solids and the yellow-emissive amorphous solid can be inter-converted by the grinding of crystalline solids and exposure of the amorphous solid to vapors of appropriate solvents. It is also demonstrated that microrods of 1a, 1b, and 1d show typical optical waveguiding behavior. more...

Eight examples of potassium N-arylbenzimidates, [K2{OCPhN(2-R1,6-R2,4-R3C6H2)}2]n (R1 = R2 = R3 = H K1; R1 = R2 = H, R3 = Me K2; R1 = R2 = H, R3 = OMe K3; R1 = R2 = H, R3 = F K4; R1 = R2 = H, R3 = Cl K5; R1 = R2 = H, R3 = NO2 K6; R1 = R3 = H, R2 = Me K7; R1 = R2 = Me, R3 = H K8), have been prepared and characterized by spectroscopic and analytical techniques. In addition, the molecular structures of K6(3THF) and K7 were determined and shown to consist of two-dimensional coordination polymers involving combinations of π-aryl and NO2-/N-donor interactions. In the presence of benzyl alcohol (BnOH), K1 - K8 all showed high efficiency for the ROP of e-caprolactone (e-CL) and L-lactide (L-LA), affording linear polyesters (PCL and PLA) with BnO or CH3O end-groups (the latter derived from the quenching solvent). By contrast, lower conversions were achievable when the runs were performed in the absence of BnOH. Mechanistic studies have indicated that for runs performed with BnOH, monomer activation by benzyl alkoxide and N-arylbenzimidate were competitive pathways for the ROP of both cyclic esters. Furthermore, the nature of the N-aryl substituents influenced the ROP of e-CL and L-LA in distinct ways. For example, K1 and K6 showed lower conversions of e-CL than that observed for K2 - K5, K7 and K8, while the conversions of L-LA using K1 - K3 and K6 exceeded that shown by K4, K5, K7 and K8. In addition, the type of solvent greatly affected their catalytic efficiency with hexane and toluene proving superior to THF and CH2Cl2 in the ROP of e-CL. Conversely, for L-LA almost quantitative conversions were observed in THF, CH2Cl2 and toluene while hexane was less effective. Furthermore, kinetic studies of the ROP of L-LA performed at different run temperatures highlighted the beneficial effect of higher temperature. more...

To investigate fine structure in biological samples, over recent decades, super-resolution methods in light microscopy have been honed. Here, we report a technique integrating nonlinearity arising from fluorophore saturation with a new version of I5S to produce quasi-isotropic three-dimensional (3D) wide-field (WF) super-resolution imaging. This extended technique—saturated I5S (SI5S)—promises lateral and axial resolutions below 60 nm when the illuminating light intensity approaches the saturation threshold in simulation. A linear processing algorithm is used to acquire SI5S image reconstructions, and comparisons with 3D structured illumination microscopy (3D-SIM) and I5S show that a substantial improvement in resolution can be realized using SI5S. The notable improvement in 3D resolution means that SI5S could facilitate volumetric visualization of intracellular fine structure within biological samples. more...

Both second-order nonlinear optical and single-molecule magnet properties are observed in a novel 1D homochiral Zn–Dy heterometallic left-handed helical chain complex (1) without chiral ligands, which evolves from a Zn3Dy2 pentanuclear cluster complex (2), thanks to the structural guiding role of perchlorate anions. more...

A facile post-synthetic modification of a tetracationic tetraimidazolium macrocycle, 14+ (i.e., the “Texas-sized” molecular box (cyclo[2](2,6-di(1H-imidazol-1-yl)pyridine)[2](1,4-dimethylenebenzene)), is described. Under mild basic conditions, ring-opening of the imidazolium moieties occurs. This results in two new isomeric dicationic macrocycles. This simple yet efficient modification serves to alter the size of the molecular cavity, the charge of the macromolecular receptor, and the manner whereby it interacts with dianionic guest molecules. The isomeric mixture of imidazolium ring opened macrocycles can be synthesized in relatively high overall yield (86–93%). The reaction shows regioselectivity and the ratio of major to minor (i.e., trans : cis ring-opened products) was determined to be ca. 3 : 1 via1H NMR spectroscopy. The major isomer, trans-cyclo[2]((Z)-N-(2-((6-(1H-imidazol-1-yl)pyridin-2-yl)amino)vinyl)formamide)[2](1,4-bismethylbenzene) hexafluorophosphate (22+·2PF6−), was isolated in its pure form in 42% yield via recrystallization. The molecular recognition properties of 22+ were investigated using a series of dianionic guests (i.e., 2,6-naphthalenedicarboxylate (4), 2,6-naphthalenedisulfonate (5), and 1,5-naphthalenedisulfonate (6)) whose binding interactions with 14+ have been previously reported. This allowed us to evaluate how imidazolium ring-opening affects the inherent host/guest interactions of 14+. On the basis of solution spectroscopic studies (e.g., 1H NMR, 1H–1H COSY NMR, DOSY NMR, and NOESY NMR), in tandem with mass spectrometric analyses (ESI-MS) and single-crystal X-ray diffraction studies, we conclude that opening up the macrocyclic structure (i.e., converting 14+ to 22+) leads to considerable changes in the recognition behavior, with so-called outside binding or weak ion pair interactions, rather than pseudorotaxane formation, being favored both in solution and the solid-state. We postulate that methodologies such as those described herein could provide a means to control the molecular interactions of both free-standing macrocycles and those used to construct mechanically-interlocked molecules. Indeed, the application of hydroxide anion under the present conditions not only serves to effect the ring-opening of 14+, but also pseudorotaxane structures, such as, e.g., [14+·4] or [14+·5] derived there from. more...

Two isostructural dense lanthanide metal–organic frameworks derived from an extended ligand 1,3,5-tris(4-carboxyphenyl)benzene (H3BTB), [Ln(BTB)H2O]n (Ln = Eu, 1; Ln = Dy, 2), which are constructed via a cross-like folding assembly strategy, were yielded by ‘two-step warming solvothermal synthesis’. Complex 1 shows luminescence while complex 2 exhibits field-induced two-step magnetic relaxation. more...

Herein we describe a scalable four-step preparation of α-methylene-γ-lactone 3 from steroidal sapogenin. This method allowed a facile synthesis of clionamine D, a natural aminosteroid with potent autophagy bioactivity and unprecedented chemical structure. more...

Two trinucleating ligands N(CH2-m-C6H4-CH(2)tacn)(3) (L1, tacn = 1,4,7-triazacyclononane) and 1,3,5-C6H3(o-C6H4-CH2N(CH(2)py)(2))(3) (L2, py = pyridine) were synthesized, and their tricopper(II) complexes [(CuCl)(3)L1]Cl-3 (1) and [(CuCl)(3)L-2]Cl-3 (2) were investigated as catalysts for the hydrolysis of 4-nitrophenyl phosphate (NPP). Structural analysis revealed that the three Cu(II) ions in L1 are adjacent to each other, while those in L2 lack such features due to the steric hindrance of dipicolylamine (dpa) units. Hydrolysis results indicated that vicinal metal ions within same ligand backbone have high levels of cooperation for substrate recognition and thus high initial catalytic efficiency, but the binding of inorganic phosphate as the hydrolysis product at the tricopper site is a major disadvantage. Significantly, complex [((CuCl)-Cl-II)(3)(HPO4)L1](PF6) (3) was isolated from NPP hydrolysis with 1 and was characterized by single crystal X-ray diffraction. In this structure, the triply bridging phosphate at the tricopper site disorders in two opposite orientations. These results, in collaboration with high-resolution mass spectrometry studies, indicated that NPP was first coordinated at the tricopper site, and was subsequently attacked by a water molecule from the underneath of the tricopper plane, a reaction model that supports the proposed mechanism of biological phosphate hydrolysis at the trimetallic active site of pyrophosphatases. (C) 2015 Elsevier B.V. All rights reserved. more...

Silver acetylide complex [Ag(ArC≡C)]n (Ar = 3,5-di-tert-butylphenyl) with unprecedented high solubility in common organic solvents has been designed and synthesized. The high solubility is due to two bulky tert-butyl substituents on the phenyl ring. This feature is significant to construct and isolate single crystals of all-alkynyl-stabilized silver clusters, which are crucial to investigate the intrinsic binding interaction and coordination modes between Ag(I) and ethynide ligands. Crystallization of [Ag(ArC≡C)]n under various conditions resulted in three high-nuclearity homoleptic silver acetylide clusters, namely, [Ag21(ArC≡C)20](OH) (1), [Ag16(ArC≡C)16] (2), and [Ag15(ArC≡C)15] (3). Complex 1 has a [Ag21] cluster protected by twenty 3,5-di-tert-butyl-phenylethynide ligands. Complexes 2 and 3 have neutral [Ag16] and [Ag15] clusters, respectively. In addition to these homoleptic silver clusters, two new silver acetylides [Ag20(ArC≡C)16(CH3COO)4] (4) and [Ag22(ArC≡C)16(NO3)4(CH3CH2OH)4](OH)2 (5) were syn... more...

A series of 1-(2,6-dibenzhydryl-4-fluorophenylimino)- 2-aryliminoacenaphthylene derivatives (L1-L5) and their halonickel complexes LNiX2 (X=Br, Ni1-Ni5; X=Cl, Ni6-Ni10) are synthesized and well characterized. The molecular structures of representative complexes Ni2 and Ni4 are confirmed as the distorted tetrahedron geometry around nickel atom by the single crystal X-ray diffraction. Upon activation with methylaluminoxane, all nickel complexes show high activities up to 1.49 x 10(7) g of PE (mol of Ni)(-1) h(-1) toward ethylene polymerization, producing polyethylenes with high branches and molecular weights up to 1.62 x 10(6) g mol(-1) as well as narrow polydispersity. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1369-1378 more...

A series of 1-(2,4-dibenzhydryl-6-chlorophenylimino)-2-aryliminoacenaphthylene derivatives (L1-L5) was synthesized and reacted with nickel halides to form the corresponding nickel complexes LNiX2 (X = Br, Ni1-Ni5; X = Cl, Ni6-Ni10). The molecular structures of representative complexes Ni2 and Ni5 were determined by single crystal X-ray diffraction, indicating the distorted square planar geometry around the nickel atom of complex Ni2 and the distorted tetrahedral geometry around the nickel atom of complex Ni5, respectively. Upon activation with low amounts of ethylaluminium sesquichloride (Et3Al2Cl3, EASC), all nickel complexes exhibited high activities up to 1.09 x 10(7) g of PE per mol of Ni per h toward ethylene polymerization, producing branched polyethylenes. Most importantly, these systems showed good thermo-stability, even at 80 degrees C maintaining the activity with 3.76 x 10(6) g of PE per mol of Ni per h. more...

A rapid, accurate and specific high-performance liquid chromatographic -tandem mass spectrometry method has been validated for the simultaneous determination of cefoperazone and sulbactam in a small volume sample for children. A Shim-pack XR-ODS C18 column with gradient elution of water (0.1% formic acid) and acetonitrile (0.1% formic acid) solution was used for separation at a flow rate of 0.3 mL/min. The calibration curves of two analytes in serum showed excellent linearity over the concentration ranges of 0.03-10 μg/mL for cefoperazone, and 0.01-3 μg/mL for sulbactam, respectively. This method involves simple sample preparation steps and was validated according to standard FDA and EMA guidelines in terms of selectivity, linearity, detection limits, matrix effects, accuracy, precision, recovery, and stability. This assay can be easily implemented in clinical practice to determine concentrations of cefoperazone and sulbactam in children. more...