Polyoxometalate-Intercalated Tremella-Like CoNi-LDH Nanocomposites for Electrocatalytic Nitrite-Ammonia Conversion.

The electrocatalytic reduction of NO2- (NO2RR) holds promise as a sustainable pathway to both promoting the development of emerging NH3 economies and allowing the closing of the NOx loop. Highly efficient electrocatalysts that could facilitate this complex six-electron transfer process are urgently desired. Herein, tremella-like CoNi-LDH intercalated by cyclic polyoxometalate (POM) anion P8W48 (P8W48/CoNi-LDH) prepared by a simple two-step hydrothermal-exfoliation assembly method is proposed as an effective electrocatalyst for NO2- to NH3 conversion. The introduction of POM with excellent redox ability tremendously increased the electrocatalytic performance of CoNi-LDH in the NO2RR process, causing P8W48/CoNi-LDH to exhibit large NH3 yield of 0.369 mmol h-1 mgcat-1 and exceptionally high Faradic efficiency of 97.0% at -1.3 V vs the Ag/AgCl reference electrode in 0.1 M phosphate buffer saline (PBS, pH = 7) containing 0.1 M NO2-. Furthermore, P8W48/CoNi-LDH demonstrated excellent durability during cyclic electrolysis. This work provides a new reference for the application of POM-based nanocomposites in the electrochemical reduction of NO2- to obtain value-added NH3.

The water-soluble inclusion complex of ilexgenin A with ß-cyclodextrin polymer--a novel lipid-lowering drug candidate.

A new water-soluble inclusion complex of ilexgenin A (IGA) with ß-cyclodextrin polymer (CDP) was prepared by a facile strategy and characterized by (1)H NMR , FT-IR, and UV-vis spectroscopy. Compared with IGA and the inclusion complex of IGA with ß-cyclodextrin (IGA-CD), the solubility of IGA-ß-cyclodextrin polymer (IGA-CDP) was greatly enhanced due to the water-soluble CDP host. The ratio of ß-cyclodextrin (ß-CD) units in CDP to IGA was determined as 2 : 1. KD of the inclusion complex was evaluated as 2.6 × 10(-3) mol L(-1). The effects of IGA-CDP on a hyperlipidemia mouse model were studied by intragastric administration. After 4 weeks, the IGA-CDP treatment resulted in decreased serum levels of total cholesterol and low-density lipoprotein-cholesterol. The effects of IGA-CDP on serum apolipoprotein levels were similar to its effects on lipid levels. By comparing liver area, the effects of IGA-CDP on pre-existing lesions were assessed. Furthermore, the efficacy and potency of water-soluble inclusion complex of IGA-CDP was 2-3 times higher than that of IGA. Taken together, it was possible to develop it to a novel drug candidate to regulate lipid abnormality.

Electrogenerated trisbipyridyl Ru(II)-/nitrilotriacetic-polypyrene copolymer for the easy fabrication of label-free photoelectrochemical immunosensor and aptasensor: application to the determination of thrombin and anti-cholera toxin antibody.

A bifunctional copolymer was electrogenerated, which allows efficient bioreceptor immobilization and transduction of the biorecognition event. This copolymer was formed using pyrenebutyric acid Nα',Nα-bis(carboxymethyl)-L-lysine amide (NTA-pyrene) and [tris-(2,2'-bipyridine) (4,4'-bis(4-pyrenyl-1-ylbutyloxy)-2,2'-bipyridine] ruthenium(II) hexafluorophosphate (Ru(II)-pyrene) complex. The pyrene groups, present in both compounds, undergo oxidative electropolymerization on platinum electrodes. The resulting copolymer contains NTA moieties, which were used as a versatile immobilization system for biotin- and histidine-tagged biomolecules, while Ru(II)-pyrene was employed as a photoelectrochemical transducing molecule. The efficiency of this copolymer for biomolecule anchoring was investigated with biotin- and histidine- tagged glucose oxidases, biotin-tagged cholera toxin and a histidine-tagged thrombin aptamer. The constructed enzyme electrodes exhibited an amperometric response toward glucose at 0.6 V vs SCE, demonstrating the anchoring of this enzyme via two coordination systems. An immunosensor configuration based on the immobilization of biotin-tagged cholera toxin was applied to the detection of anti-cholera antibody while the aptasensor based on the immobilization of histidine-tagged thrombin aptamer was tested for thrombin determination. The biorecognition events were monitored via the evolution of the photocurrent intensity generated by the polymerized Ru(II)-pyrene in the presence of visible light and a sacrificial donor (ascorbate). The binding of the targets hinders the diffusion of the sacrificial donor, inducing thus a photocurrent decrease. The constructed immunosensor presents a specific label-free photoelectrochemical response to anti-cholera antibody without labeling step, the detection limit being 0.2 µg mL⁻¹. The label-free photoelectrochemical response of the aptasensor varies linearly with thrombin concentrations up to 10 pmol L⁻¹, the detection limit being 1×10⁻¹³ mol L⁻¹.

Lanthanide-ion-tuned magnetic properties in a series of three-dimensional cyano-bridged Ln(III)W(V) assemblies.

The reaction of [W(CN)(8)](3-) with Ln(3+) and pyrazine in acetonitrile yielded a series of isostructural compounds formulated as Ln(H(2)O)(4)(pyrazine)(0.5)W(CN)(8) (Ln = La(1), Ce(2), Pr(3), Nd(4), Sm(5), Eu(6), Gd(7)). The Ln(III) and W(V) centers in the structure are linked through cyanide groups to form two-dimensional (2D) layers, which are further pillared by pyrazine, generating 3D frameworks. The magnetic behavior for compounds 1-7 were driven by the lanthanide ions involved. The Ln(III) and W(V) ions in compounds 2 and 5 are ferromagnetically coupled with magnetic ordering occurring at 2.8 K, comparable with magnetic ordering with the critical temperature of 1.9 K for compound 4. In addition, the antiferromagnetic interactions were observed in compounds 3 and 7, while no significant magnetic couplings were found in compounds 1 and 6.

Efficient synthetic strategy to construct three-dimensional 4f-5d networks using neutral two-dimensional layers as building blocks.

The reaction of neutral two-dimensional (2D) layer Tb(H(2)O)(5)W(CN)(8) with pyrazine in the acetonitrile solution has led to a 3D bimetallic complex, Tb(H(2)O)(4)(pyrazine)(0.5)W(CN)(8) (1). In the structure of 1, the eight-coordinated W center adopts a slightly distorted dodecahedron, while the Tb center exhibits a nine-coordinated slightly distorted tricapped trigonal prism. The Tb(3+) atoms and the [W(CN)(8)](3-) units are linked in alternating fashion in the ab crystallographic plane, resulting in an infinite 2D corrugated layers. The linear bis-monodentate pyrazine ligands acting as pillars link adjacent layers along the c axis to form an extended 3D open framework. The possible formation mechanism is proposed, and the temperature has played a crucial role for the formation of 1. Magnetic measurements revealed the presence of ferromagnetic interaction between Tb(III) and W(V) centers. 1 marks the first structural pattern using the neutral 2D layer as building block and the first 3D complex with Ln(III)-[W(V)(CN)](8) found in octacyanometallate-based system. Such a novel and effective building-block methodology will provide a new attractive path forward in developing functionalities of 3D 4f-5d system and may provide an opportunity to obtain 3D magnet in 4f-5d assembly.

4-(4-Pyrid-yl)pyridinium 3-amino-5-carb-oxy-2,4,6-triiodo-benzoate-5-amino-2,4,6-triiodo-isophthalic acid (1/1).

In the title ammonium carboxyl-ate-carb-oxy-lic acid co-cystal, C(10)H(9)N(2) (+)·C(8)H(3)I(3)NO(4) (-.)C(8)H(4)I(3)NO(4), the carboxyl-ate anion and carb-oxy-lic acid mol-ecule are linked by O-H⋯O and N-H⋯O hydrogen bonds to form a chain running along the c axis of the monoclinic unit cell. The chains are linked by pyridinum and pyridine N-H⋯O hydrogen bonds, generating a layer motif. O-H⋯N and O-H⋯O hydrogen bonds are also observed.

(5-Amino-isophthalato-κN)triaqua-(1,10-phenanthroline-κN,N')cobalt(II) trihydrate.

The Co(II) atom in the title compound, [Co(C(8)H(5)NO(4))(C(12)H(8)N(2))(H(2)O)(3)]·3H(2)O, is six-coordinated in a CoN(3)O(3) octa-hedral geometry; the water-coordinated Co(II) atom is chelated by the N-heterocycle. An inter-molecular N-H⋯O hydrogen bond occurs. The carboxyl-ate entity coordinates through the amino group. The carboxyl-ate donor unit, coordinated and uncoordinated water mol-ecules inter-act through O-H⋯O and N-H⋯O hydrogen bonds, generating a tightly-held three-dimensional cage-like network.

Tetra-kis(1H-imidazole-κN)(2-phenyl-propanedioato-κO,O)nickel(II).

In the title complex, [Ni(C(9)H(6)O(4))(C(3)H(4)N(2))(4)], the Ni(II) ion is O,O'-chelated by the phenyl-malonato ligand and coordinated by four imidazole ligands in a slightly distorted octa-hedral geometry. In the crystal structure, symmetry-related mol-ecules are linked by N-H⋯O hydrogen bonds, generating a three-dimensional network.