Novel Hybrids Constructed from Keggin-Polyoxometalate and Mixed Copper Complex

Abstract  Two new Keggin-polyoxometalate hybrids, {[Cu₂(4,4′-bpy)₂][PW₁₀^VIW₂^VO₄₀]}[Cu₂(obpy)₂]₄ · 2 H₂O (1) and {[Cu₄(2,2′-bpy)₄(4,4′-bpy)₃][SiW₁₂O₄₀]} · 2H₂O (2) (4,4′-/2,2′-bpy = 4,4′-/2,2′-bipyridyl, Hobpy = 6-hydroxy-2,2′-bipyridyl), were hydrothermally synthesized and structurally characterized. Gillard type hydration of 2,2′-bipy is observed during the synthesis of 1, resulting in a new obpy ligand in situ. X-ray structural analyses show that 1 consists of 1D hybrid chain {[Cu₂(4,4′-bpy)₂][PW₁₀^VIW₂^VO₄₀]}_∞ and [Cu₂(obpy)₂] dimer, whereas 2 possesses 1D hybrid structure based on Keggin-type [SiW₁₂O₄₀]⁴⁻ anions and tetra-nuclear copper complexes [Cu₄(2,2′-bpy)₄(4,4′-bpy)₃]⁴⁺. Both compounds present interesting supramolecular architectures based on π–π stacking and hydrogen bonds. Graphical Abstract  Compounds {[Cu₂(4,4′-bpy)₂][PW₁₂O₄₀]}[Cu₂(obpy)₂]₄ · 2H₂O (1) and [Cu₄(2,2′-bpy)₄(4,4′-bpy)₃][SiW₁₂O₄₀] · 2H₂O (2) were hydrothermally synthesized. 1 features that the [Cu₂(obpy)₂] dimers based on in situ generated obpy ligands are stumped between the layers where 1D hybrid chain {[Cu₂(4,4′-bpy)₂][PW₁₂O₄₀]}_∞ locates, while 2 exhibits 1D chain-like structure based on anions [SiW₁₂O₄₀]⁴⁻ and tetra-copper complexes [Cu₄(2,2′-bpy)₄(4,4′-bpy)₃]⁴⁺.      

The fractal dimension as estimator of the fractional content of metal matrix composite materials

Electrochemical techniques are applied to estimate the fractal dimension value of electroactive surface structures. However, the fractal dimension value is an abstract concept, which sometimes is hard to understand. Herein, this abstract concept is used to calculate the fractional content of the nickel/graphite–polypropylene hybrid composite material, putting into practice this concept in the study of composite materials.     

A Thermally and Hydrolytically Stable Microporous Framework Exhibiting Single‐Chain Magnetism: Structure and Properties of [Co2(H0.67bdt)3]⋅20 H2O

Fixing a hole : Hydrothermal chemistry has been exploited in the preparation of a 3D framework material exhibiting 48 % accessible void volume and 1.5 % hydrogen uptake by weight at 120 kPa (see picture). The title compound also exhibits single‐chain magnetic behavior and reversible changes in magnetic properties upon solvation and desolvation.

     

Incorporation of Fe3O4 Nanoparticles into Organometallic Coordination Polymers by Nanoparticle Surface Modification

Surface‐modified Fe ₃ O ₄ nanoparticles (NPs) can be obtained by substituting [(η⁵‐semiquinone)Mn(CO)₃] for oleylamine surface protecting groups. The resulting NP can function as a nucleus or template to generate crystalline coordination polymers that contain superparamagnetic Fe₃O₄ NPs. Hybridized magnetic properties can be obtained by introducing paramagnetic metal nodes, such as Mn²⁺, into the polymers (see picture).

     

[Al4(OH)2(OCH3)4(H2N‐bdc)3]⋅x H2O: A 12‐Connected Porous Metal–Organic Framework with an Unprecedented Aluminum‐Containing Brick

Al together now! A new stable aluminum aminoterephthalate system contains octameric building blocks that are connected by organic linkers to form a 12‐connected net (see picture). The structure adopts a cubic centered packing motive in which octameric units replace individual atoms, thus forming distorted octahedral (red sphere) and tetrahedral cages (green spheres) with effective accessible diameters of 1 and 0.45 nm, respectively.

     

Oligothiophene Self‐Assembly on the Surface of ZnO Nanorods: Toward Coaxial p–n Hybrid Heterojunctions

We describe herein the design, synthesis and detailed structural characterization of hybrid 1D nanostructures. They are prepared by supramolecular self‐assembly of oligothiophene molecules on the surface of zinc oxide nanorods in solution at room temperature. Electronic absorption spectroscopy and X‐ray diffraction show that both organic and inorganic components in the coaxial p–n heterojunctions are crystalline. Especially, it is demonstrated that the organic compounds form a self‐assembled monolayer at the surface of the nanorods, which is not the case when zinc oxide quantum dots are instead used. As a result of their hybrid nature, the 1D nanostructures lead to ambipolar semiconducting nanostructured materials as active layers in field‐effect transistors.     

Reachability sets of hybrid systems in the presence of successive switchings

The concept of reachability domains of hybrid systems is described together with the use of ellipsoidal methods for calculation of such domains in the case when there are successive switchings on several given hyperplanes or bands. An algorithm for calculation of the reachability sets for a hybrid system that uses ellipsoidal approximations is given for the cases in which the switching sets are planes or bands. The parametrization of nonconvex reachability domains is obtained as a union of intersections of the corresponding ellipsoidal estimates.     

Hybrid Dynamics of Stochastic π-Calculus

In this paper we describe a method to map stochastic π-calculus processes in chemical ground form into hybrid automata. Hybrid automata are tools widely employed to model systems characterized by both discrete and continuous evolution and their use in the context of Systems Biology allows us to address rather fundamental issues. Specifically, the key ingredient we use in this work is the possibility granted by hybrid automata to implement a separation of control and molecular terms in biochemical systems. The computational counterpart of our analysis turns out to be related to the determination of conservation properties of the system.      

Langmuir monolayer properties of the fluorinated-hydrogenated hybrid amphiphiles with dipalmitoylphosphatidylcholine (DPPC)

Surface pressure–area (π–A), surface potential–area (ΔV–A), and dipole moment–area (μ–A) isotherms were obtained for the Langmuir monolayer of two fluorinated-hydrogenated hybrid amphiphiles (sodium phenyl 1-[(4-perfluorohexyl)-phenyl]-1-hexylphosphate (F6PH5PPhNa) and (sodium phenyl 1-[(4-perfluorooctyl)-phenyl]-1-hexylphosphate (F8PH5PPhNa)), DPPC and their two-component systems at the air/water interface. Monolayers spread on 0.02 M Tris buffer solution (pH 7.4) with 0.13 M NaCl at 298.2 K were investigated by the Wilhelmy method, ionizing electrode method and fluorescence microscopy. Moreover, the miscibility of two components was examined by plotting the variation of the molecular area and the surface potential as a function of the molar fraction for the fluorinated-hydrogenated hybrid amphiphiles on the basis of the additivity rule. The miscibility of the monlayers was also examined by construction of two-dimensional phase diagrams. Furthermore, assuming the regular surface mixture, the Joos equation for analysis of the collapse pressure of two-component monolayers allowed calculation of the interaction parameter (ξ) and the interaction energy (−Δ) between the fluorinated-hydrogenated hybrid amphiphiles and DPPC. The observations by a fluorescence microscopy also supported our interpretation as for the miscibility in the monolayer state. Comparing the monolayer behavior between the two binary systems, no remarkable difference was found among various aspects. Among the two combinations, the mole fraction dependence in monlayer properties was commonly classified into two ranges: 0 ≤ X ≤ 0.3 and 0.3 < X ≤ 1. Dependence of the chain length of fluorinated part was reflected for the molecular packing and surface potential.