Electrochemical Detection of Flutamide by the Composite of Complex Based on Thiacalix[4]arene Derivatives and Reduced Graphene Oxide.

In this paper, a thiacalix[4]arene complex [Zn2(TIT4A)L2]·4DMF·2CH3OH (H2L = 4,4'-oxybisbenzoic acid) (Zn-TIT4A-L) was synthesized by a solvothermal method. The composites were prepared by combining Zn-TIT4A-L with reduced graphene oxide (RGO), mesoporous carbon (MC), and multi-walled carbon nanotubes (MWCNTs), respectively. Three representative composites are Zn-TIT4A-L@RGO(1:1), Zn-TIT4A-L@MC(1:2), and Zn-TIT4A-L@MWCNT(1:2). X-ray diffraction and scanning electron microscopy characterized their structures and morphologies. The results showed that three composites were successfully prepared, and the crystals of the complex remained in the composites. The electrochemical properties of the composites were characterized by electrochemical impedance spectroscopy and cyclic voltammetry. The results indicated that they had good electrocatalytic activity and conductivity. Among them, Zn-TIT4A-L@RGO(1:1) had the best performance and was used for the quantitative detection of flutamide (FTA). The linear range of detection is 0.1-200 µM, and the limit of detection is 0.015 µM. At the same time, the sensor also had good reproducibility, anti-interference, and stability. The sensor was also used for the detection of FTA in lake water, human urine, and serum with a satisfactory recovery rate. The possible mechanism of electrochemical detection of FTA was also discussed.

Single-Component White Light Emission from a Metal-Coordinated Cyclotriveratrylene-Based Coordination Polymer.

A coordination polymer, namely, [Cd3L(H2O)3]·DMA·4H2O (1) (DMA = N,N-dimethylacetamide), was prepared by the solvothermal reaction of cyclotriveratrylene-based ligand 5,6,12,13,19,20-hexacarboxy-methoxy-cyclotriveratrylene (H6L) and Cd(NO3)2·4H2O. In 1, a two-dimensional structure was constructed by the connection of hexanuclear Cd-O clusters and L6- anions. Photoluminescence measurements indicated that 1 displayed tunable photoluminescence through the variation of the excitation wavelength. Significantly, the white light emission of 1 can be observed with a broad excitation wavelength range from 320 to 385 nm. When 1 is excited by 385 nm light, its chromatic coordinate is (0.29, 0.34), which is located very close to the pure white light region (0.33, 0.33). Meanwhile, the color temperature (CCT) is 7994 K, which corresponds well to "cold" white light.

Simultaneous electrochemical detection of gallic acid and uric acid with p-tert-butylcalix[4]arene-based coordination polymer/mesoporous carbon composite.

Design and synthesis of an efficient electrocatalyst for simultaneous determination of gallic acid (GA) and uric acid (UA) is vital in the biological field. Herein, we synthesized a new p-tert-butylcalix[4]arene-based metal-organic electrocatalyst (Mn-L@MC) by combining Mn-L (H4L = tetrakis[(2-biphenylcarboxyl)oxy]-p-tertbutylcalix[4]arene) and mesoporous carbon (MC) via a simple mechanical grinding method. Synergistic effect between Mn-L and MC made the Mn-L@MC composite behave high-efficiency electrocatalytic performance toward simultaneous detection of GA and UA. Under optimal experimental conditions, the Mn-L@MC-2 electrode material featured relatively wide linear range (0.5-90 µM) for the two analytes, and low determination limits of 0.043 µM for GA and 0.059 µM for UA. The remarkable electrochemical detection behavior of Mn-L@MC-2 electrode material toward GA and UA are comparable to those known sensors containing precious metals. The Mn-L@MC-2 material exhibited high selectivity, superior reproducibility, and acceptable stability during the determination of the two analytes. The sensor was assembled to simultaneously detect GA and UA in healthy human urine with satisfactory recoveries.

Thiacalix[4]arene-based complex with Co(II) ions as electrode modifier for simultaneous electrochemical determination of Cd(II), Pb(II), and Cu(II).

A complex [Co4(TCTA)2(H2O)8]∙10H2O (Co-TCTA) based on thiacalix[4]arene derivative has been synthesized for the first time using the solvothermal method. The glassy carbon electrode (GCE) modified with Co-TCTA (Co-TCTA/GCE) could simultaneously determine Cd2+, Pb2+, and Cu2+ at around - 0.75 V, - 0.60 V, and - 0.10 V (vs. ref. Ag/AgCl) and had good stability, selectivity, and reproducibility with relative standard deviation (RSD) of 4.4% for Cd2+, 1.4% for Pb2+, and 5.4% for Cu2+. Co-TCTA/GCE showed wide linear range of 0.4-8.0 µM for Cd2+, 0.4-7.0 µM for Pb2+, and 0.6-6.0 µM for Cu2+ when three ions were determined simultaneously. The limits of detection (LODs) of Cd2+, Pb2+, and Cu2+ were 0.071 µM, 0.022 µM, and 0.021 µM, respectively. Moreover, the sensor was used to determine three ions in lake water sample with satisfactory recoveries of 93.6-93.8% for Cd2+, 93.8-103.3% for Pb2+ and 94.6-95.3% for Cu2+. The good adsorption capacity of Co-TCTA and Co(II)/Co(0) circular mechanism on the surface of the electrode were proposed to enhance the electrochemical signals. This work enriched the theoretical research on the complexes for the determination of heavy metal ions.

Self-Assembly of Polyoxometalate-Resorcin[4]arene-Based Inorganic-Organic Complexes: Metal Ion Effects on the Electrochemical Performance of Lithium Ion Batteries.

With their adjustable structures and diverse functions, polyoxometalate (POM)-resorcin[4]arene-based inorganic-organic complexes are a kind of potential multifunctional material. They have potential applications for lithium ion batteries (LIBs). However, the relationship between different coordinated metal ions and electrochemical performance has rarely been investigated. Here, three functionalized POM-resorcin[4]arene-based inorganic-organic materials, [Co2 (TMR4 A)2 (H2 O)10 ][SiW12 O40 ]⋅2 EtOH⋅4.5 H2 O (1), [Ni2 (TMR4 A)2 (H2 O)10 ][SiW12 O40 ]⋅4 EtOH⋅13 H2 O (2), and [Zn2 (TMR4 A)2 (H2 O)10 ][SiW12 O40 ]⋅2 EtOH⋅2 H2 O (3), have been synthesized. Furthermore, to enhance the conductivities of these compounds, 1-3 were doped with reduced graphene oxide (RGO) to give composites 1@RGO-3@RGO, respectively. As anode materials for LIBs, 1@RGO-3@RGO can deliver very high discharge capacities (1445.9, 1285.0 and 1095.3 mAh g-1 , respectively) in the initial run, and show discharge capacities of 898, 665 and 651 mAh g-1 , respectively, at a current density of 0.1 A g-1 over 100 runs. More importantly, the discharge capacities of 319, 283 and 329 mAh g-1 were maintained for 1@RGO-3@RGO even after 400 cycles at large current density (1 A g-1 ).

Three Resorcin[4]arene-Based Two-Dimensional Zn(II) Supramolecular Isomers Synthesized via a Structure-Directing Strategy for Knoevenagel Condensation.

Herein, in the presence of three structure-directing agents (SDAs), a family of imidazole-functionalized resorcin[4]arene-based coordination polymers (CPs), [Zn(TIC4R)(HCOO)]·HCOO·0.5DMF·1.5H2O (1), [Zn(TIC4R)(CN)]·HCOO·DMF·2.5H2O (2), and [Zn(TIC4R)(H2O)]·2HCOO·2H2O (3), were assembled under solvothermal conditions [TIC4R = tetra(imidazole) resorcin[4]arene]. 1 exhibits a double-layer structure with rectangle windows, and 2 and 3 display monolayer structures. The layers of CPs 2 and 3 are slides with different offsets along the a-axis. In addition, three CPs were used as catalysts to catalyze Knoevenagel condensations. Strikingly, all CPs exhibit remarkable catalytic performance for several substrates. To the best of our knowledge, this is the first time that a small organic acid as SDA was used in the syntheses of resorcin[4]arene-based supramolecular isomers.

Polyoxometalate-Templated Cobalt-Resorcin[4]arene Frameworks: Tunable Structure and Lithium-Ion Battery Performance.

By employing a bowl-like tetra(benzimidazole)resorcin[4]arene (TBR4A) ligand, two new polyoxometalate-templated metal-organic frameworks (POMOFs), [Co8Cl14(TBR4A)6]·3[H3.3SiW12O40]·10DMF·11EtOH·20H2O (1) and [Co3Cl2(TBR4A)2(DMF)4]·[SiW12O40]·2EtOH·3H2O (2), have been prepared under solvothermal conditions (DMF = N,N'-dimethylformamide). 1 shows a 2D cationic layer, whereas 2 exhibits a 3D framework. Remarkably, the Keggin POMs in 1 and 2 were located in the cavities formed by two bowl-like resorcin[4]arenes in sandwich fashions. Their framework structures were highly dependent on the coordination modes of the TBR4A ligands. To increase the conductivity of POMOFs, the samples of 1 and 2 were loaded on the conductive polypyrrole-reduced graphene oxide (PPy-RGO) via ball milling (1@PG and 2@PG). Then, the obtained composites experienced calcination at a proper temperature to produce 1@PG-A and 2@PG-A. The resulting 1@PG-A and 2@PG-A composites, with improved conductivities, uniform sizes and micropores, exhibited promising electrochemical performance for lithium-ion batteries. We herein proposed a size-controlled route for the rational fabrication of functional POMOFs and their usage in energy fields.

A Porous Metal-Organic Framework as an Electrochemical Sensing Platform for Highly Selective Adsorption and Detection of Bisphenols.

The design of artificial receptors with a specific recognition function and enhanced selectivity is highly desirable in the electrochemical sensing field, which can be used for detection of environmental pollutants. In this facet, metal-organic frameworks (MOFs) featured adjustable porosities and specific host-guest recognition properties. Especially, the large hydrophobic cavity formed in the porous MOFs may become a potential artificial receptor. We herein designed a new porous MOF [Zn2(L)(IPA)(H2O)]·2DMF·2MeOH·3H2O (Zn-L-IPA) by using a functionalized sulfonylcalix[4]arene (L1) and isophthalic acid (H2IPA) (DMF = N,N'-dimethylformamide). The specific pore size and pore shape of Zn-L-IPA made it efficiently selective for absorption of bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS). Therefore, a rapid, highly selective, and ultrasensitive electrochemical sensing platform Zn-L-IPA@GP/GCE was fabricated by using Zn-L-IPA as a host to recognize and absorb bisphenol guests (GP = graphite powder, GCE = glassy carbon electrode). Most strikingly, the extremely low detection limits were up to 3.46 and 0.17 nM for BPA and BPF, respectively, using the Zn-L-IPA@GP/GCE electrode. Furthermore, the "recognition and adsorption" mechanism was uncovered by density functional theory with the B3LYP function. This work offered a prospective strategy for selective absorption and detection of harmful bisphenols with the MOF-based porous material.

Efficient Catalytic Oxidative Desulfurization toward Thioether and Sulfur Mustard Stimulant by Polyoxomolybdate-Resorcin[4]arene-Based Metal-Organic Materials.

The design and synthesis of effective and recyclable oxidative desulfurization catalysts is of great importance in view of environmental protection and human health. Herein, a family of polyoxomolybdate-based inorganic-organic hybrid materials, namely, [Mn(TMR4A)(H2O)4][Mo6O19]·0.5CH3CH2OH·H2O (1), [Ni(TMR4A)(H2O)4][Mo6O19]·0.5CH3CH2OH·H2O (2), [Zn(TMR4A)(H2O)4][Mo6O19]·0.5CH3CH2OH·H2O (3), and [Co2(TMR4A)2(H2O)4(ß-Mo8O26)]·CH3CN·12H2O (4), were assembled by the functionalized resorcin[4]arene ligand (TMR4A) with polyoxomolybdate and metal ions under solvothermal conditions. In isostructural 1-3, the [M(TMR4A)(H2O)4]2+ species (M = MnII, NiII, ZnII) and [Mo6O19]2- anions are held together via C-H···O hydrogen bonds to give a 3D supramolecular architecture. In 4, two [Co(TMR4A)(H2O)2]2+ cations were linked by one [ß-Mo8O26]4- anion to produce an attractive molecular dimer. Remarkably, 1-4, as recyclable heterogeneous catalysts, exhibit efficient catalytic oxidation desulfurization activities toward thioethers. Particularly, 1, as a representative example, features selective catalytic oxidation for sulfur mustard simulant. Moreover, their electrochemical properties were also studied.

A Nanosized Propeller-like Polyoxometalate-linked Copper(I)-Resorcin[4]arene for Efficient Catalysis.

The design and assembly of polyoxometalate-resorcin[4]arene-based metal-organic molecular materials are particularly attractive for their elegant structures and potential functions. By applying a newly designed resorcin[4]arene ligand (TPC4R-II), a copper(I)-coordinated polyoxometalate-based metal-organic molecular material, namely, [CuI6(Br)3(TPC4R-II)3(PMo12O40)]·8H2O (1), was rationally assembled. Three copper(I)-coordinated resorcin[4]arenes are held together by a central [PMo12O40]3- to yield a supramolecular propeller. 1 features efficient catalytic performances for oxidation desulfurization (ODS) and azide-alkyne cycloaddition (AAC) reactions. This work affords a feasible method for the nanosized polyoxometalate-based metal-resorcin[4]arene assemblies by well combinating two types of large composites as well as low coordination metal cations.

Highly Stable Copper(I)-Thiacalix[4]arene-Based Frameworks for Highly Efficient Catalysis of Click Reactions in Water.

Environmentally friendly metal-organic frameworks (MOFs) have gained considerable attention for their potential use as heterogeneous catalysts. Herein, two CuI -based MOFs, namely, [Cu4 Cl4 L]⋅CH3 OH⋅1.5 H2 O (1-Cl) and [Cu4 Br4 L]⋅DMF⋅0.5 H2 O (1-Br), were assembled with new functionalized thiacalix[4]arenes (L) and halogen anions X- (X=Cl and Br) under solvothermal conditions. Remarkably, catalysts 1-Cl and 1-Br exhibit great stability in aqueous solutions over a wide pH range. Significantly, MOFs 1-Cl and 1-Br, as recycled heterogeneous catalysts, are capable of highly efficient catalysis for click reactions in water. The MOF structures, especially the exposed active CuI sites and 1D channels, play a key role in the improved catalytic activities. In particular, their catalytic activities in water are greatly superior to those in organic solvents or even in mixed solvents. This work proposes an attractive route for the design and self-assembly of environmentally friendly MOFs with high catalytic activity and reusability in water.

A Calix[4]resorcinarene-Based [Co12] Coordination Cage for Highly Efficient Cycloaddition of CO2 to Epoxides.

The design and synthesis of polynuclear metal cluster-based coordination cages is of considerable interest due to their appealing structural characteristics and potential applications. Herein, we report a calix[4]resorcinarene-based [Co12] coordination cage, [Co12(TPC4R-I)2(1,3-BDC)10(µ3-OH)4(H2O)10(DMF)2]·7DMF·23H2O (1), assembled with 2 bowl-shaped calix[4]resorcinarenes (TPC4R-I), 10 angular 1,3-benzenedicarboxylates (1,3-BDC), and 12 Co(II) cations. Remarkably, it is shown to be a highly efficient recyclable heterogeneous catalyst for CO2 conversion due to its exposed Co(II) Lewis acid sites.

Polyoxometalate-Bridged Cu(I)- and Ag(I)-Thiacalix[4]arene Dimers for Heterogeneous Catalytic Oxidative Desulfurization and Azide-Alkyne "Click" Reaction.

Two remarkable polyoxometalate-bridged Cu(I)- and Ag(I)-thiacalix[4]arene dimers, namely, [Cu4(SiW12O40)(L)2(DMF)2]·2EtOH·DMF (1-Cu) and [Ag4(PMo12O40)(L)2]·OH (1-Ag), were prepared by using a new thiacalix[4]arene, metal cation and polyoxometalate (L = tetra[2-(ethylthio)-1-methyl-1H-imidazole]-thiacalix[4]arene). In 1-Cu and 1-Ag, two thiacalix[4]arenes were linked together by one [SiW12O40]4- or [PMo12O40]3- anion via two metal cations to give a molecular dimer. Further, adjacent dimers were extended into a high-dimensional supramolecular architecture through hydrogen bonds. Markedly, these molecular dimers are exceedingly stable in organic solvents and then were employed as efficient catalysts for catalytic oxidation desulfurization as well as the azide-alkyne "click" reaction.

Intraventricular infusion of clusterin ameliorated cognition and pathology in Tg6799 model of Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is characterized by the deposition of amyloid-ß (Aß) in brain parenchyma and cerebral blood vessels as cerebral amyloid angiopathy (CAA). Clusterin, a chaperon protein associated with Aß aggregation, toxicity and transport through blood-brain barrier, may play a key role in the development of AD. Recently, clusterin peptide D-[113-122] was shown to mimic clusterin's function and exerted therapeutic effect in atherosclerosis. In this study, we investigated whether this clusterin peptide also affected (Aß) deposition in AD transgenic mouse. RESULTS: Using a micropump, synthetic peptide 113-122 of clusterin protein (20 µg/200 µl) was infused into the lateral ventricle of 8-month 5 × FAD transgenic mouse model (Tg6799), for 2 weeks. Water-maze testing showed an improved cognitive function of the Tg6799 mice treated with clusterin. Immunocytochemistry and quantitative analysis revealed that intraventricular (icv) administration of clusterin peptide in Tg6799 mouse reduced Aß plaques as well the severity of cerebral amyloid angiopathy. Enzyme-linked immunosorbent assay demonstrated a decreased in the soluble levels of Aß (Aß40 and Aß42) in the brain. Western-blot revealed an increased level of LRP-2 after clusterin peptide treatment. CONCLUSION: These results suggest that icv infusion of clusterin peptide D-[113-122] offers a promising therapeutic approach to reduce Aß deposition as well as CAA. The LRP2-mediated clearance system might be involved in the mechanism of these effects.

Water-Stable Metal-Organic Framework for Effective and Selective Cr2O72- Capture through Single-Crystal to Single-Crystal Anion Exchange.

Effective and selective capture of environmentally toxic Cr2O72- from water is desirable for both environment protection and human health, but it still remains a significant challenge. We present a water-stable cationic metal-organic framework (MOF) with large nanotubular channels ( ca. 1.4 × 1.4 nm2), (1-Cl). Remarkably, the resulting porous material exhibits rapid aqueous-phase removal of Cr2O72- via an anion-exchange manner. Meaningfully, the capture and separation of aqueous Cr2O72- are highly selective even in the presence of other disturbing anions. More importantly, the crystal structure of 1-Cl after anion exchange (1-Cr2O7) could be determined by single crystal X-ray diffraction, elaborating the single-crystal-to-single-crystal (SC-SC) transformation. The Cr2O72- removal process by 1-Cl thus was directly uncovered by the crystal structure of Cr2O72--incorporated 1-Cr2O7.

Current approaches for the management of Parkinson's disease in Chinese hospitals: a cross-sectional survey.

BACKGROUND: Chinese guidelines for management of Parkinson's disease (PD) have been issued and updated regularly since 2006. We undertook a cross-sectional survey to evaluate the impact of the latest edition (2014) on current approaches to the management of PD based on previous pilot works. METHODS: Seven hundred and seventeen participants, divided into 3 groups (GPs, Neurologists, and Specialists), recruited from 138 randomly chosen hospitals from 30 cities across China, participated by completing the questionnaire describing their current approaches before and after the guidelines were issued. RESULTS: Considerable discrepancies in management were apparent across the three categories, with different selection of first-choice medication for PD patients. There were also variations in management of concurrent psychiatric symptoms and dementia. Notably, over 50% of participants reported improvements in PD recognition and management by following the guidelines. CONCLUSIONS: The increasing use of Chinese clinical practice guidelines for PD management is having a positive impact on the optimization of care, which in turn offers important economic benefits.

Versatile Assembly of Metal-Coordinated Calix[4]resorcinarene Cavitands and Cages through Ancillary Linker Tuning.

We propose a design strategy for assembly of metal-coordinated calix[4]resorcinarene cavitands and cages by tuning of the ancillary linkers. Assembly of newly functionalized cavitand with angular isophthalic acid analogs affords three intriguing metal-coordinated cavitands with deep cavities, 1a-1c. Further, by mediating appropriate spacers between two isophthalic acids, two bowl-shaped cavitands are successfully joined together to produce three elegant coordination cages with tunable sizes and shapes, 2a-2c. The cavitand and cage crystals possess considerable amount of accessible porosities, as clearly established by gas adsorption measurements. Remarkably, 1a-1c also exhibit high structural flexibilities, reversibly transforming between the open-pore and the narrow-pore structures, upon removal and sorption of guest molecules, as evidenced by diffraction and gas adsorption measurements. By combining experimental studies with density functional theory (DFT) calculations, we thoroughly elucidated the mechanism of the structural transformations in response to external stimuli in this new class of flexible porous solids.

A Polyoxovanadate-Resorcin[4]arene-Based Porous Metal-Organic Framework as an Efficient Multifunctional Catalyst for the Cycloaddition of CO2 with Epoxides and the Selective Oxidation of Sulfides.

In this work, we report a new polyoxovanadate-resorcin[4]arene-based metal-organic framework (PMOF), [Co2L0.5V4O12]·3DMF·5H2O (1), assembled with a newly functionalized wheel-like resorcin[4]arene ligand (L). 1 features an elegant porous motif and represents a rare example of PMOFs composed of both a resorcin[4]arene ligand and polyoxovanadate. Remarkably, 1 shows open V sites in the channel, which makes 1 an efficient heterogeneous Lewis acid catalyst for the cycloaddition of carbon dioxide to epoxides with high conversion and selectivity. Strikingly, 1 also exhibits high catalytic activity for the heterogeneous oxidative desulfurization of sulfides. Particularly, the heterogeneous catalyst 1 can be easily separated and reused with good catalytic activity.

A Stable Porphyrin-Based Porous mog Metal-Organic Framework as an Efficient Solvent-Free Catalyst for C-C Bond Formation.

We herein report the porous 4-fold interpenetrated mog (moganite) metal-organic framework (MOF) [Cd3(tipp)(bpdc)2]·DMA·9H2O (1·Cd; H2tipp = 5,10,15,20-tetrakis(4-(imidazol-1-yl)phenyl)porphyrin, H2bpdc = biphenyl-4,4'-dicarboxylic acid, DMA = N,N'-dimethylacetamide). The incorporation of Cd and carboxylate oxygen affords 1·Cd rich Lewis acid and basic sites. This MOF 1·Cd was then applied as an efficient heterogeneous catalyst for the important cyanosilylation of aldehydes and Knoevenagel condensation reactions. 1·Cd features excellent catalytic performance and recyclability for the cyanosilylation of various aldehydes with trimethylsilyl cyanide (TMSCN). Moreover, 1·Cd shows highly efficient catalysis and substrate selectivity for Knoevenagel condensation reactions of various aldehydes with malononitrile. The high catalytic activity and stability toward C-C bond formation make 1·Cd a promising heterogeneous catalyst.

[Research in rheological properties of four types of ophthalmic preparations].

This study is prepared to provide the basis of rheological parameters for the additional quality standard of ophthalmic gels, the rheological properties of the ophthalmic gels and the other three types of ophthalmic preparations. The medicines were compared through the study of the rheological properties for four types of ophthalmic preparations. The cone-plate rheometer was used to determine the dynamic and steady rheological parameters of four types of ophthalmic preparations. The similarities and differences of the measured results were analyzed to summarize the rheological indexes and parameters which are applied to distinguish the ophthalmic gels and the other types of ophthalmic preparations. 1 The elastic modulus should be greater than the viscous modulus for the ophthalmic gels in the range of the linear viscoelastic region. 2 The ophthalmic gels should be shear thinning non-Newtonian fluid with a certain yield stress and thixotropy. 3 The dynamic viscosity of the ophthalmic gels should be greater than 0.5 Pa·S at the temperature of 25 ℃ with the 50 s-1 shear rate. The typical rheological indexes and parameters of the ophthalmic gels were proposed in this article. The determination methods are simple and feasible. The rheological indexes and parameters have an important significance in the prescription design, production technology and quality control of the ophthalmic gels.