Cucurbituril-Encapsulating Metal-Organic Framework via Mechanochemistry: Adsorbents with Enhanced Performance.

The first examples of monolithic crystalline host-guest hybrid materials are described. The reaction of 1,3,5-benzenetricarboxylic acid (H3 BTC) and Fe(NO3 )3 ⋅9 H2 O in the presence of decamethylcucurbit[5]uril ammonium chloride (MC5⋅2 NH4 Cl⋅4 H2 O) directly affords MC5@MIL-100(Fe) hybrid monoliths featuring hierarchical micro-, meso- and macropores. Particularly, this "bottle-around-ship" synthesis and one-pot shaping are facilitated by a newly discovered Fe-MC5 flowing gel formed by mechanochemistry. The designed MC5@MIL-100(Fe) hybrid material with MC5 as active domains shows enhanced CH4 and lead(II) uptake performance, and selective capture of lead(II) cations at low concentrations. This shows that host-guest hybrid materials can exhibit synergic properties that out-perform materials based on individual components.

The Relevance of Size Matching in Self-assembly: Impact on Regio- and Chemoselective Cocrystallizations.

Decamethonium diiodide is reported to perform the chemo- and regioselective encapsulation of para-dihalobenzenes through the competitive formation of halogen-bonded cocrystals starting from solutions that also contain ortho and meta isomers. Selective caging in the solid occurs even when an excess ortho or meta isomers, or even a mixture of them, is present in the solution. A prime matching between the size and shape of the dication and the formed dianions plays a key role in enabling the selective self-assembly, as proven by successful encapsulation of halogen-bond donors as weak as 1,4-dichlorobenzene and by the results of cocrystallization trials involving mismatching tectons. Encapsulated para-dihalobenzenes guest molecules can be removed quantitatively by heating the cocrystals under reduced pressure and be recovered as pure materials. The residual decamethonium diiodide can be recycled with no reduction in selectivity.

Monodispersed Ag nanoparticles as catalyst: preparation based on crystalline supramolecular hybrid of decamethylcucurbit[5]uril and silver ions.

Monodispersed silver nanoparticles (Ag(0) NPs) have been first prepared on the basis of a postsynthesis via mild reduction from a new crystalline supramolecular hybrid solid assembled from Ag(+) ions and decamethylcucurbit[5]uril (Me10CB[5]). Uniform growth of nearly spherical Ag(0) NPs with an average size of ca. 4.4 nm was observed on the organic Me10CB[5] support to form Ag@Me10CB[5] composite material. The as-synthesized composite material was characterized by a range of physical measurements (PXRD, TGA, XPS, ICP, TEM, etc.) and was further exploited as a heterogeneous catalyst for the reduction of various nitrophenols in the presence of NaBH4. The kinetics of the reduction process was monitored under various experimental conditions. The Ag@Me10CB[5] composite material showed excellent catalytic performance over the reduction reactions and remained active after several consecutive cycles.

Crystalline hybrid solid materials of palladium and decamethylcucurbit[5]uril as recoverable precatalysts for Heck cross-coupling reactions.

A series of MPdMe10 CB[5] (M=Li, Na, K, Rb, and Cs; Me10 CB[5]=decamethylcucurbit[5]uril) hybrid solid materials have been successfully synthesized for the first time through a simple diffusion method. These as-prepared hybrid solids have been applied as phosphine-free precatalysts for Heck cross-coupling reactions with excellent catalytic performance and good recyclability. In the processes of the catalytic reactions, the activated Pd(II) species were released from the crystalline hybrid precatalysts and transformed into catalytically active Pd nanoparticles, which have been demonstrated as key to carry on the catalytic reactions for the recoverable precatalysts MPdMe10 CB[5] (M=K, Rb, and Cs). It has also been rationalized that the introduction of different alkali metals afforded crystalline hybrid precatalysts with different crystal structures, which are responsible for their diversified stability and reusability presented in Heck reactions.

Multinuclear Solid-State Magnetic Resonance as a Sensitive Probe of Structural Changes upon the Occurrence of Halogen Bonding in Co-crystals.

Although the understanding of intermolecular interactions, such as hydrogen bonding, is relatively well-developed, many additional weak interactions work both in tandem and competitively to stabilize a given crystal structure. Due to a wide array of potential applications, a substantial effort has been invested in understanding the halogen bond. Here, we explore the utility of multinuclear ((13)C, (14/15)N, (19)F, and (127)I) solid-state magnetic resonance experiments in characterizing the electronic and structural changes which take place upon the formation of five halogen-bonded co-crystalline product materials. Single-crystal X-ray diffraction (XRD) structures of three novel co-crystals which exhibit a 1:1 stoichiometry between decamethonium diiodide (i.e., [(CH3)3N(+)(CH2)10N(+)(CH3)3][2 I(-)]) and different para-dihalogen-substituted benzene moieties (i.e., p-C6X2Y4, X=Br, I; Y=H, F) are presented. (13)C and (15)N NMR experiments carried out on these and related systems validate sample purity, but also serve as indirect probes of the formation of a halogen bond in the co-crystal complexes in the solid state. Long-range changes in the electronic environment, which manifest through changes in the electric field gradient (EFG) tensor, are quantitatively measured using (14)N NMR spectroscopy, with a systematic decrease in the (14)N quadrupolar coupling constant (CQ) observed upon halogen bond formation. Attempts at (127)I solid-state NMR spectroscopy experiments are presented and variable-temperature (19)F NMR experiments are used to distinguish between dynamic and static disorder in selected product materials, which could not be conclusively established using solely XRD. Quantum chemical calculations using the gauge-including projector augmented-wave (GIPAW) or relativistic zeroth-order regular approximation (ZORA) density functional theory (DFT) approaches complement the experimental NMR measurements and provide theoretical corroboration for the changes in NMR parameters observed upon the formation of a halogen bond.

New types of hybrid solids of tetravanadate polyanions and cucurbituril.

Three inorganic-organic hybrid solids based on tetravanadate polyanions, {V(4)O(12)}(4-) and cucurbituril, Me(10)Q[5] and Q[5], namely (NH(4))(4)[(V(4)O(12))·(Me(10)Q[5]@0.5H(2)O)(2)]·âˆ¼13H(2)O (1), Li(4)(H(2)O)(5)[(V(4)O(12))·(Me(10)Q[5]@H(2)O)(2)]·âˆ¼20H(2)O (2), and Na(4)(H(2)O)(2)[(V(4)O(12))·(Q[5])(2)]·âˆ¼15H(2)O (3), have been synthesized under hydrothermal conditions. In the structure of compound 1, two {Me(10)Q[5]@0.5H(2)O} moieties connect to one {V(4)O(12)}(4-) cluster through an NH(4)(+) counter-cation to form a trimer unit, which further forms a three-dimensional (3D) supramolecular architecture via extensive hydrogen bonds (H-bonds). Compound 2 contains a one-dimensional (1D) covalently bonded chain structure built by alternate {Me(10)Q[5]@H(2)O} moieties and {Li(2)O(4)(H(2)O)(3)}(2+) dimer units. The anionic {V(4)O(12)}(4-) units bond to every another {Li(2)O(4)(H(2)O)(3)}(2+) dimer unit sitting on the chain through multi-uncoordinated water molecules via H-bonds. Compound 3 is built from {V(4)O(12)}(4-) clusters, Q[5], and sodium cations into a two-dimensional (2D) covalent wavy structure, showing interesting connection between the building units, which is packed into 2D through plentiful H-bonds. It has been found that the cations dramatically affect the coordination of the tetravanadate polyanion and cucurbituril.

Photochromic hybrid materials of cucurbituril and polyoxometalates as photocatalysts under visible light.

Two isostructural organic-inorganic hybrid solid materials based on cucurbituril derivatives and polyoxometalates, {[K(2)(H(2)O)(2)Na(2)(H(2)O)(2)Na(2)(H(2)O)(6)](P(2)W(18)O(62))(Me(10)Q(5))(2)}·~7H(2)O (1) and {[Rb(2)(H(2)O)(2)Na(2)(H(2)O)Na(2)(H(2)O)(4)](P(2)W(18)O(62))(Me(10)Q(5))(2)}·~8H(2)O (2), which exhibit reversible photochromic properties as well as excellent photocatalytic activities toward the degradation of methyl orange (MO) and rhodamine-B (RB) under visible light irradiation, are reported.

Homochiral nickel coordination polymers based on salen(Ni) metalloligands: synthesis, structure, and catalytic alkene epoxidation.

One-dimensional (1D) homochiral nickel coordination polymers [Ni(3)(bpdc)(RR-L)(2)·(DMF)](n) (2R, RR-L = (R,R)-(-)-1,2-cyclohexanediamino-N,N'-bis(3-tert-butyl-5-(4-pyridyl)salicylidene), bpdc = 4,4'-biphenyldicarboxylic acid) and [Ni(3)(bpdc)(SS-L)(2)·(DMF)](n) (2S, SS-L = (S,S)-(-)-1,2-cyclohexanediamino-N,N'-bis(3-tert-butyl-5-(4-pyridyl)salicylidene) based on enantiopure pyridyl-functionalized salen(Ni) metalloligand units NiL ((1,2-cyclohexanediamino-N,N'-bis(3-tert-butyl-5-(4-pyridyl)salicylidene))Ni(II)) have been synthesized and characterized by microanalysis, IR spectroscopy, solid-state UV-vis spectroscopy, thermogravimetric analysis (TGA), circular dichroism (CD) spectroscopy, cyclic voltammetric measurement, and powder and single crystal X-ray diffraction. Each NiL as unbridging pendant metalloligand uses one terminal pyridyl group to coordinate achiral unit (nickel and bpdc(2-)) building a helical chain, while the other pyridyl group remains uncoordinated. Both 2R and 2S contain left- and right-handed helical chains made of the achiral building blocks, while the NiL as remote external chiral source is perpendicular to the backbone of the helices. The nickel coordination polymers 2R and 2S containing unsaturated active nickel center in metalloligand NiL can be used as self-supported heterogeneous catalysts. They show catalytic activity comparable with their homogeneous counterpart in alkene epoxidation and exhibit great potential as recyclable catalysts.

Development of a polyoxometallate-based photocatalyst assembled with cucurbit[6]uril via hydrogen bonds for azo dyes degradation.

A water insoluble cucurbit[6]uril-polyoxometallates (CB[6]-POMs) composite assembled from α-Keggin type polysilicontungstate anions and macrocycle cucurbit[6]uril (CB[6]) via hydrogen bonding has been synthesized as visible light active photocatalyst. The physical and photocatalytic properties of such photocatalyst have been fully characterized by PXRD, FTIR, TG, XPS, and UV/vis diffuse reflectance spectra. The catalyst shows a good photocatalytic activity towards the degradation of methyl orange (MO) under visible light irradiation and displays good reproducibility of photocatalytic degradation by a simple recycled procedure without obvious loss in catalytic activity, which is of great significance for practical use of the photocatalyst. In the photodegradation process, the {Ni-CB[6]}(n) chain of the photocatalyst acts as sensitizer and can be induced by visible light, meanwhile the POMs chain of the photocatalyst acts as electron acceptor and deposits the electron in its LUMO. The effects of various experimental parameters and the proposed mechanisms are discussed in detail.

Facile synthesis of palladium nanoparticles with high chemical activity using cucurbit[6]uril as protecting agent.

Using cucurbit[6]uril as protecting agent, well-defined Pd NPs were prepared via a simple one-pot method under mild conditions. The CB[6]-Pd NPs are very stable and have high chemical activities for catalyzing Suzuki-Miyaura cross-coupling reactions.

pH-Dependent syntheses and crystal structures of a series of organic-inorganic hybrids constructed from Keggin or Wells-Dawson polyoxometalates and silver coordination compounds.

A series of silver complexes of polyoxometalates (POMs), formulated as, [Ag(2)(4,4'-bpy)(2)(4,4'-Hbpy)(H(2)O)][PW(12)O(40)] (4,4'-bpy = 4,4'-bipyridine, 1), [Ag(4)(4,4'-bpy)(4)][4,4'-H(2)bpy][P(2)W(18)O(62)].4H(2)O (2), [Ag(4)(4,4'-bpy)(4)][H(2)P(2)W(18)O(62)].7H(2)O (3), and Na(8)[Ag(3)(4,4'-bpy)(3)][PW(10)Ag(2)O(39)].6H(2)O (4), have been hydrothermally synthesized in situ at different pH. Complex 1, based on saturated Keggin POM building blocks and silver coordination compounds, exhibits an interesting 3-fold interpenetration of diamondlike network in the POM chemistry. Different from complex 1, complexes 2-3 consist of Wells-Dawson polyoxoanions and silver coordination compounds. Complex 2 represents the highest coordination number of Wells-Dawson polyoxoanions, which helps to form a high-dimensional framework with (4.6(4).8)(4)(4(4).6(16).8(8)) topology. Thee-dimensional (3D) Wells-Dawson phosphotungstate 3 reveals another new topology (4.6(4).7)(4.6(4).8)(2)(4(3).6(8).7(2).8(2)). Complex 4 forms a 3D framework constructed from divacant Keggin polyoxoanions and silver coordination compounds. Their structural differences indicate that the pH value of the reaction system plays a key role on the structures and topologies of these complexes, and the whole self-assembly process is pH-dependent.

[Expression of Aurora-B in non-small cell lung cancer and its clinical significance].

OBJECTIVE: To study the expression of Aurora-B in non-small cell lung cancer (NSCLC) tissues and NSCLC cell lines. METHOD: Aurora-B expression was examined using immunohistochemical SP method in 91 stage I and 69 stage II-III NSCLC tissues and 40 adjacent tissues. The mRNA and protein expressions of Aurora-B in NSCLC cell lines (A549, H460 and H1299) were examined by RT-PCR and Western blotting, respectively. RESULTS: The protein expression of Aurora-B was detected in 77.7% (94/121) of the tumor tissues and 9.8% (4/41) of the adjacent tissues, showing a significant difference between them (P<0.01). The positivity rate of Aurora-B protein was not related with the gender and age of NSCLC patients, but with lymph node metastasis, differentiation and histological type of NSCLC (P<0.05). Aurora-B was expressed in all the NSCLC cell lines (A549, H460 and H1299) at both mRNA and protein levels. A549 cells showed the highest expression of Aurora-B. CONCLUSION: Aurora-B protein is highly expressed in NSCLC tissues and cell lines, and may play a crucial role in the invasion, metastasis and development of NSCLC. The mRNA and protein expression levels of Aurora-B differ significantly between different NSCLC cell lines.

Systematic investigation on the coordination chemistry of a sulfonated monoazo dye: ligand-dominated d- and f-block derivatives.

Ten coordination compounds based on a sulfonated monoazo dye, formulated as M(H(2)O)(2)(4,4'-abs)(2) (M = Mn , Co , Cu , Zn , Cd and Pb ; 4,4'-abs = 4-aminoazobenzene-4'-sulfonic anion), Ag(4,4'-abs) (), [Ln(H(2)O)(phen)(2)(4,4'-abs)(3)].3H(2)O (Ln = Gd , Tb , and Ho ; phen = 1,10-phenanthroline), as well as the parent ligand L [(4,4'-Habs)(2).4H(2)O] and precursor NaL.HL [Na(4,4'-abs)(4,4'-Habs)] were successfully isolated. Structural analyses revealed that the structures of compounds, and vary according to the coordination geometries of the metal ions, and vary from double-strand chain structures () to a 3-D pillared-layer framework to mononuclear complexes. The double-strand chain structures of are isostructural, and are built on octahedral metal centers and double bridging 4,4'-abs ligands coordinating via terminal N- and O-donors. The silver-containing compound displays a pillared-layer structure constructed from 4.8(2) silver sulfonate nets pillared by the linear backbones of 4,4'-abs ligands. Compounds , which are also isostructural, possess mononuclear structures consisting of a metal cation, three 4,4'-abs anions, two auxiliary phen ligands, one aqua ligand and three non-coordinated water molecules. Evidence on two series of isostructural compounds indicates that structures of d- and f-block metal derivatives are dominated by the coordination mode of the ligands. The surface chemistry of compound has been investigated based on the LBL (layer-by-layer) technique. The as-synthesized multilayer films with different composite components exhibit different surface behaviours.

Supramolecular assembly from decavanadate anion and decamethylcucurbit[5]uril.

Three supramolecular compounds constructed from decamethylcucurbit[5]uril (Me(10)Q(5)) and decavanadate [H(2)V(10)O(28)](4-) were synthesized and characterized.

[Evaluation on the analytical sensitivity of 31 HBsAg enzyme immunoassay kits].

OBJECTIVE: To study the analytical sensitivity on 31 HBsAg enzyme immunoassy (EIA) test kits. METHODS: Thirty one HBsAg EIA kits produced by domestic or overseas manufactories and applied for approval during May 2007 to May 2008, were evaluated using the national reference panels. The hyperbolic curve of the log A value and log concentration for the national sensitivity standards was established. The cut-off value of each kit was substituted into the curvilinear equation to determine the analytical sensitivity which was compared between different HBsAg EIA kits. RESULTS: Twenty seven (351 lots) domestic and 4 (27 lots) overseas kits were compared. Among 378 lots of the 31 HBsAg EIA kits, only 2 lots of the domestic kits had a lower sensitivity when tested with the national HBsAg reference panels, with an average approvalr ate of 99.43% (349/351). The mean analytical sensitivity of the domestic kits for adr, adw, ay serotypes were 0.307, 0.419, 0.513 ng/ml, respectively. There was a significant difference between serotypes (F = 97.30, P < 0.01). The mean analytical sensitivity of the overseas kits for adr, adw, ay serotypes were 0.054, 0.066, 0.050 ng/ml respectively, with no significant difference between serotypes (F = 0.65, P > 0.05). The analytical sensitivity of the overseas kits for all the three serotypes was higher than that of the domestic kits (P < 0.01). There was no significant difference found between the analytical sensitivities of the kits produced by the same manufactory using 30- or 60-minute incubation of detection (P > 0.05). In contrast, there was significant difference noticed between the analytical sensitivities of the kits produced by the same manufactory when tested for 10 or 15-minute coloration of the results (P < 0.01). CONCLUSION: Analytical sensitivity of the HBsAg EIA domestic kits should be further improved, especially for detecting adw and ay serotypes.

[Preparation and application of the national reference panel for hepatitis B virus DNA].

OBJECTIVES: To calibrate the national hepatitis B virus (HBV) DNA standard according to world health organization's standard material and prepare the national reference panel for HBV DNA reagents. METHODS: Sera from blood donors and HBV patients were collected and detected by home-made HBV DNA PCR kits, HBsAg kits, and anti-HBc kits, and then confirmed by HBV DNA PCR kits produced by Roche in German, which was recognized by the world health organization. The stability of the panel was detected by acceleration method. RESULTS: The convinced copies of the sensitivity samples were gotten by seven independent experiments, the coefficients of variation of logarithm of the copies of L0-L5 were all less than 15%. Regarding the national reference panel as the standard, the quality of most domestic HBV DNA PCR kits was improved, while part of the kits should be further qualified. CONCLUSION: The national reference panel for HBV DNA reagents is developed. It contains eight negative, nine positive sera and seven samples for sensitivity test

Prevalence, isolation, and partial sequence analysis of hepatitis E virus from domestic animals in China.

Evidence that hepatitis E is zoonotic is accumulating. Serum samples were collected from pigs, cattle, and goats from various regions of China to determine whether they had been infected with hepatitis E virus (HEV). An in-house enzyme immunoassay (EIA) and reverse transcriptase-polymerase chain reaction (RT-PCR) with primers from open reading frame (ORF) 2 were used to detect anti-HEV antibodies and HEV RNA. The mean positivity rates of anti-HEV antibody for pigs and cattle were 78.8% and 6.3% but none of the goat sera were positive. Pigs may be more susceptible to infection with HEV than cattle or goats. Five of 263 pig sera were positive for HEV RNA and four of these five were also positive for anti-HEV. The PCR products (nt 6007-6354) were cloned and sequenced and compared to other HEV sequences in the nucleotide databases. The five sequences shared 83-93% identity to each other at the nucleotide level and 74-79%, 73-74%, 73-78%, and 83-99% identity to HEV genotypes 1, 2, 3, and 4, respectively. They were closely related to human isolates of HEV genotype 4. Phylogenetic analyses also place these swine sequences in HEV genotype 4, resembling most closely viruses isolated from Chinese patients with acute hepatitis. These data support the hypothesis that sporadic hepatitis E in China is zoonotic.