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Au nanoparticle-decorated Dy2(WO4)3 nanocomposites were prepared by reduction of HAuCl4 on the surface of Dy2(WO4)3 nanobelts which were synthesized by hydrothermal method. The formation of nanocomposites was confirmed by transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and UV-vis absorption spectroscopy. Au-Dy2(WO4)3 based electrochemical sensor was fabricated by spreading Au-Dy2(WO4)3 aqueous solution on the surface of glassy carbon electrode (GCE) and investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The prepared sensor exhibited excellent electrocatalytic activity, stability, reproducibility and selectivity with well-separated oxidation peaks toward the electrooxidation of uric acid (UA) and nitrite (NO2−). Electrochemical determination of these two biomolecules in their mixture solution showed linear responses in the ranges of 0.04–1.0 mmol/L with a detection limit of 15 μmol/L for UA, and 0.01–1.0 mmol/L with a detection limit of 3.5 μmol/L for NO2−. The sensor can be applied in determination of UA and NO2− in human urine samples.

Single-crystalline Mn3O4 nanoflakes were grown on manganese sheets by one-step thermal oxidation process at 360–500 °C in ambient atmosphere. The samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Raman and transmission electron microscope (TEM). The nanoflakes with a size of 15–20 nm in thickness, ~60 nm in width, and ~210 nm in length are obtained at 360 °C for 24 h. A surface diffusion mechanism is proposed to explain the growth of manganese oxide nanostructures via thermal oxidation, which includes two steps: manganese oxide (MnO/Mn3O4) layers form firstly, and then Mn3O4 nanostructures grow above the upper metal oxide layer to form multi-layered structures, MnO/Mn3O4/Mn3O4–nanoflakes. The nucleation and growth of Mn3O4 nanostructures are related to the surface energy and different growth rates along different crystal directions, which are controlled by the diffusion of the metal and gas molecule.

A novel graphene oxide sheets/polyaniline/CdSe quantum dots (GO/PANi/CdSe) nanocomposites were successfully synthesized and used for the sensitive electrochemiluminescence (ECL) biosensing. The GO/PANi/CdSe nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), ultraviolet–visible (UV–vis) absorption spectroscopy, photoluminescence (PL) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Finally, the nanocomposites were employed to construct the biosensor via layer-by-layer assembly for the ECL detection of Cytochrome C (Cyt C). The whole process was characterized by cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS). Experimental parameters such as the ratio of GO/PANi, the K 2 S 4 O 8 concentration and the pH value of electrolyte solution were studied to investigate the effect on the ECL intensity. Under the optimized conditions, the ECL intensity decreased linearly with the Cyt C concentrations in the range from 5.0×10 −8 to 1.0×10 −4 M with detection limit of 2.0×10 −8 M. Besides, the as-proposed biosensor exhibits high specificity, good reproducibility, and stability, and may be applied in more bioanalytical systems.

Graphene is a single layer of carbon atoms in a closely packed honeycomb lattice. As a new class of two-dimensional nanomaterial, graphene has attracted considerable attention in terms of both the experimental and theoretical aspects in recent years. The unique nanostructure and its other properties endow graphene with potential applications such as capacitors, cell images, sensors, devices, drug delivery, and solar cells. This review presents a general description of preparation route for graphene and its composites in the last few years. The new developments and improvements in its electrochemical applications in inorganic analysis, organic analysis, immunoassay and other electrochemical fields are also discussed.

By employing functional diimine ligands coordinated dipalladium(II,II) or diplatinum(II,II) clips as corners and the coplanar 4,4'-bipyrazolate dianion (L(2-)) ligand as linker, a series of bipyrazolate-bridged metallo-macrocycles, namely, [M8L4](NO3)8 (M = Pd(dmbpy), 1; Pd(bpy), 2; Pt(bpy), 3a; Pd(phen), 4; Pt(phen), 5; Pd(15-crown-5-phen), 6; Pd(18-crown-6-phen), 8; Pd(benzo-24-crown-8-phen), 10a; Pt(15-crown-5-phen), 7a, Pt(18-crown-6-phen), 9a; Pt(benzo-24-crown-8-phen), 11a) and [M6L3](NO3)6 (M = Pt(bpy), 3b; Pt(15-crown-5-phen), 7b; Pt(18-crown-6-phen), 9b; Pd(benzo-24-crown-8-phen), 10b; Pt(benzo-24-crown-8-phen), 11b), have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the 1H-bipyrazolyl ligands in aqueous solution. All these compounds have a crown-shaped cavity that can serve as host to solvent molecules and anions. The structures are characterized by elemental analysis, (1)H and (13)C NMR, ESI-MS, and in the cases of 1a (the BF4(-) salt of 1), 2a (the BF4(-) salt of 2), and 3b by single-crystal X-ray diffraction analysis. Photophysical properties for complexes 1 and 2 are discussed.

[structure: see text]. The self-assembly in aqueous solution of tripyrazolate trianion linkers (H3L = 1 and 2) with coordinated dimetallic clips leads to the formation of Pd12L4 cages with interior cavities of 1800 Angstroms3 and 1500 Angstroms3, respectively, confirmed by 1H NMR, 13C NMR, cold spray ionization mass spectrometry (CSI-MS), and single-crystal X-ray analysis.

The design and synthesis of novel polypyrazolyl aromatic bridging ligands 1,3,5-tris(3,5-dimethyl-1H-pyra- zol-4-yl)benzene and 2,4,6-tris(4-(3,5-dimethyl-1H-pyrazol-4-yl)phenyl)-1,3,5-triazine from simple starting materials mesitylene and p-tolunitrile were reported.

Two pyrazolate-bridged dinuclear Pd(II) diimine complexes {[(phen)Pd]2L2}(NO3)2 (1) and {[(bpy)Pd]2L2}(NO3)2 (2) have been synthesized through metal–metal interaction and spontaneous deprotonation from 1H-3,5-diphenylpyrazole (HL) in aqueous solution. These complexes show Pd(II)⋯Pd(II) interactions and anion binding have been characterized by elemental analyses, 1H and 13C NMR, ESI-MS, UV–Vis and luminescent spectroscopy, and single crystal X-ray diffraction methods.

In the crytal structure of the title compound, [Pd2(C56H50N8)]2(BF4)4·8CH3CN·H2O, the asymmetric 5-phenyl-3-p-tolyl­pyrazolate ligands bridge (4,4′-dimethyl-2,2′-bipyridine-κ2N,N′)palladium(II) units in cis and trans fashions, resulting in two coexistent dipalladium complexes. The six-membered rings consisting of the two Pd atoms and the four pyrazolyl N atoms have boat-shaped conformations in both independent complexes; the Pd atoms are four-coordinate in square-planar environments. The crystal structure is stabilized by electrostatic forces between the cations and anions, and weak inter­molecular hydrogen bonds involving tetraflurido­borate anions (C—H⋯F), the solvent acetonitrile mol­ecules (C—H⋯N) and water mol­ecules (C—H⋯O).

In the title complex, [Pd2(C10H12O4)2(C10H8N2)2](PF6)2·CH3CN, the PdII centers have a distorted cis-square-planar geometry defined by an O,O′-bidentate bis­acetyl­acetonate dianion ligand and a chelating 2,2′-bipyridine ligand. The crystal structure is stabilized by electrostatic forces between the cations and anions, inter­molecular π–π stacking inter­actions between pairs of 2,2′-bipyridine rings, and weak inter­molecular hydrogen bonds involving hexa­fluoro­phosphate anions (C—H⋯F) and the solvent acetonitrile mol­ecules (C—H⋯N).

The [M(3)L(3)](3+) metallo-macrocycles with syn, syn, syn conformation, self-assembled from crown ether functionalized 1,10-phenanthroline Pd(II) nitrates with naphthanoimidazole, bind a solvent CH(3)CN within the naphthanoimidazolate-built cavity through C-H...pi interactions in the crystalline state.

A series of nanosized cavity-containing bipyrazolate-bridged metallomacrocycles with dimetal centers, namely, {[(bpy)M]8L4}(NO3)8 [L=3,3',5,5'-tetramethyl-4,4'-bipyrazolyl, Pd, Pt; 1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene), Pd; and 1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbiphenyl, Pd], {[(phen)M]8L4}(NO3)8 [L=3,3',5,5'-tetramethyl-4,4'-bipyrazolyl, Pd, Pt; 1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene, Pd; and 1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbiphenyl, Pd], {[(bpy)Pd]6L3}(NO3)6 [L=1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene,], {[(phen)Pd]6L3}(NO3)6 [L=1,4-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene,], {[(bpy)Pd]4L2}(NO3)4 [L=1,3-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene, and 1,2-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene,], and {[(phen)Pd]4L2}(NO3)4 [L=1,3-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene, and 1,2-bis-4'-(3',5'-dimethyl)-pyrazolylbenzene,] (where bpy=2,2'-bipyridine and phen=1,10-phenanthroline) have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the 1H-bipyrazolyl ligands in aqueous solution. These complexes, with weak Pd(II)...Pd(II) or Pt(II)...Pt(II) interactions, have been characterized by elemental analysis, 1H and 13C NMR, cold-spray ionization or electrospray ionization mass spectrometry, UV-visible spectroscopy, and luminescence spectroscopy. Complexes and have also been characterized by single-crystal X-ray diffraction analysis.

A [3 + 3] modular self-assembly gives rise to the formation of basket-shaped, crown ether-functionalized, nano-sized trimetallo-macrocycles, which function as structural analogues of cyclotriveratrylenes (CTV).

The asymmetric unit of the title compound, μ-nitrato-bis­[(2,2′:6′,2′′-terpyridyl-κ3N)palladium(II)] hexa­kis(hexa­fluorido­phosphate) acetonitrile solvate, [Pd2(C15H11N3)2NO3]PF6·C2H3N, contains two cationic dimers, [Pd2(C15H11N3)2NO3]3+, six (PF6)− anions and one CH3CN solvent mol­ecule. Each cationic dimer is built upon (μ-1,3-NO3) bridging coordination to two cis-(2,2′:6′,2′′-terpyridine)PdII units in a cofacial arrangement. The Pd atom is four-coordinated by a tridentate chelating 2,2′:6′,2′′-terpyridine ligand and one bridging nitrate ion, to form a distorted square-planar geometry. The two dimers aggregate alternately along a linear chain via Pd⋯Pd inter­actions [intra­dimer, 3.09 (1) A; inter­dimer, 3.33 (1) A]. The dimer-to-dimer aggregates arrange in a zigzag orientation along the b axis through π–π inter­actions [centroid–centroid distances 3.521 (6)–3.894 (6)A] between terpyridine ligands and weak inter­molecular hydrogen bonds involving hexa­fluorido­phosphate anions (C—H⋯F) and the solvent acetonitrile mol­ecule (C—H⋯N).

In the crystal structure of the title compound, [Pd2(C22H17N2)2(C12H12N2)2](PF6)2·C4H10O·H2O, two Pd(dmbpy) units (dmbpy is 4,4′-dimethyl-2,2′-bipyridine) are bridged by 4-benzyl-3,5-diphenyl­pyrazolate ligands in an exodentate fashion, which results in a clip-like cavity between the two Pd(dmbpy)Pd planes. A disordered hexa­fluorido­phosphate anion is held in the cavity by an anion–π inter­action [P—F⋯Cg1 = 3.435 (15) A (Cg1 is the centroid of the Pd–dmbpy chelate ring system) and P—F⋯Cg2 = 3.187 (15) A (Cg2 is the centroid of a pyridine ring)]. A crystallographic twofold rotation axis passes through an F atom of the disordered anion and the mid-point of the two Pd atoms. The P and two F atoms of the second anion also lie on a twofold rotation axis, as do the O atom of the diethyl ether and the water O atom. The crystal structure is stabilized by electrostatic forces between the cations and anions, and inter­molecular hydrogen bonds involving hexa­fluorido­phosphate anions (C—H⋯F), the solvent diethyl ether mol­ecules and water mol­ecules (C—H⋯O).

The molecules of the title compound, C22H18N2, are connected by N—H...N hydrogen bonds, forming cyclic dimers. These dimers are linked by C—H...π hydrogen bonds involving the phenyl rings as acceptors.

In the crystal structure of the title salt, [Pd2(C15H11N2)2(C12H12N2)2](PF6)2, two (4,4′-dimethyl-2,2′-bipyridine)palladium(II) units are bridged by two pyrazolate ligands in an exodentate fashion. The six-membered ring consisting of the two Pd atoms and the four pyrazolyl N atoms has a boat-shaped conformation and the Pd atoms are four-coordinate in square-planar environments. The cation and both anions have crystallographically imposed mirror symmetry.

In the title complex, [Pd2(C10H12O4)(C12H8N2)2](PF6)2·CH3CN, the PdII centre has a distorted cis square-planar geometry defined by an O,O′-bidentate bis­acetyl­acetonate dianion ligand and a chelating 1,10-phenanthroline ligand. The crystal structure features electrostatic inter­actions between the cations and anions, inter­molecular π–π inter­actions between pairs of 1,10-phenanthroline rings, and weak hydrogen bonds involving hexa­fluoro­phosphate anions (C—H⋯F) and the acetonitrile solvent mol­ecules (C—H⋯N).

A luminescent supramolecular chiral Au16 ring with 4.822 nm perimeter that self-assembled from a tetrameric array of achiral Au2 units is described. Intra- and intermolecular Au...Au interactions play an important role in directing its chiral self-assembly.