Materials Literature
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As a means of preparation of biocompatible molecular surfaces, an alternate assembly of charged polysaccharides and oppositely-charged synthetic polymers was conducted. Cationic chitosan was assembled alternately with anionic poly(sodium styrenesulfonate) (PSS) at pH 4. Regular film growth and its dependence on ionic…
Copper–organodiamine substructures are effective bridging groups for polyoxomolybdate anions in the construction of two-dimensional mixed metal networks, of which [{Cu(bpe)}4(α-Mo8O26)]·2H2O and [{Cu(pyrd)}4(γ-H4Mo8O26)] are representative [bpe = 1,2-bis(4-pyridyl)ethylene; pyrd = pyridazine].
Strong isotropic negative thermal expansion (α = –4.2 × 10–6 K–1) found for siliceous faujasite over a temperature range of 25 to 573 K is attributed to transverse vibrations of the bridging oxygen atoms, a model supported by structural refinements of X-ray diffraction data as a function of temperature.
Reactions between [M(H2O)3(tacn)]3+ (M = Cr, Co) and [Co(CN)3(tacn)] are demonstrated to produce the molecular box clusters [Cr4Co4(CN)12(tacn)8]12+ and [Co8(CN)12- (tacn)8]12+ with core structures consisting of a single cubic unit excised from the Prussian Blue type framework.
It is shown that the solid‐state equilibrium configuration of Bi‐doped ZnO grain boundaries is a nanometer‐thick amorphous film. Polycrystalline Bi‐doped ZnO was investigated using high‐resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM). The equilibrium state below…
Polydomain films of liquid crystalline polymer ( MACB- AB6 ) with low content (6 mol %) of azobenzene units were prepared and irradiated with linearly polarized light at 366 nm, thus inducing an alignment of the photochromic side groups as well as the nonphotoactive mesogens, the cyanobiphenyl groups. An induced order…
The synthesis of a poly(thiophene) polymer with an extremely narrow bandgap is described.
The size effect in ferroelectrics is examined by considering the semiconductivity of the ferroelectric. This approach is applied to a theoretical investigation of the stability of the spontaneous polarization in a ferroelectric film on a semiconductor using a homogeneous Ginzburg-Landau theory. The band structure in t…
The luminescence properties of several 1∶1 lanthanide ion (Sm3+, Tb3+, Dy3+, Pr3+, Nd3+, Ho3+, Tm3+ and Yb3+) complexes based on the m-terphenyl-containing ligands 1–3 have been studied in methanol solutions. The organic complexes show their typical luminescence in the visible (Sm3+, Tb3+, Dy3+ and Pr3+) and in the ne…
A structural determination confirms that the tripodal ligand tris[4-(2-hydroxy-3-methoxyphenyl)-3-aza-3-butenyl]amine (LH3) offers two coordination sites, an inner N4O3 one and an outer O6 one, in which two identical or different lanthanide ions can be successively encapsulated, thus providing access to a general rout…
The intercalation of two amphiphilic cationic azobenzene derivatives into the interlayer space of montmorillonite has been conducted by the ion exchange reactions between sodium montmorillonite andp-(ω-trimethylammoniopentyloxy)-p′-(dodecyloxy)azobenzene bromide or p-(ω-trimethylammoniodecyloxy)-p′-(octyloxy)azobenzen…
This article presents an overview of the chemistry of metal complexes of dibenzotetraaza[14]annulene ligands and highlights most of the recent developments. The title tetraazamacrocycles are related to the porphyrins but have a smaller N4 coordination cavity ‘hole size’ and typically possess a non-planar, saddle-shape…
Nanocrystalline gold particles passivated with alkane- and arenethiols were deposited on microphase-separated ultrathin films of poly(styrene- block -methyl methacrylate). The nanocrystals preferentially adsorbed to the polystyrene phases over areas of the substrate as large as 10 μm 2, as seen by transmission electro…
The reaction of Pt2(dba)3 with CO leads rapidly to the formation of platinum nanoparticles. Stabilization of the particles was achieved by octanethiol or various polymers. Spectroscopic studies demonstrate the coordination of thiol at the surface of the particles. The size distribution is quasi monodisperse and center…
We present a theory of resonant quantum tunneling of large spins through thermally activated states. It gives numerical results that are in good agreement with data from recent magnetic quantum tunneling experiments in Mn acetate. We show that neither dipolar fields nor crystal-field perturbations, acting separately,…
The objective of this investigation was to clarify the influence of water-soluble polymers on the dissolution behavior of nifedipine from solid dispersions with combined carriers. All the solid dispersions of nifedipine were prepared by the fusion method using nicotinamide and 4 different water-soluble polymers, hydro…
SIMS and XPS were used to characterise the chemistry of thin plasma polymerised acrylic acid films (ppAAc), and to determine how this was influenced by plasma power. Quartz microbalance weight measurements were used to monitor the effect of power on the deposition rate and identify the uptake of water vapour by the fi…
The dimerization and tendency to form higher aggregates of two isomeric metal-free phthalocyanine compounds with tetracumylphenoxy peripheral substitution at the alpha (1 or 4, 5 or 8, 9 or 12, 13 or 16) and beta (2 or 3, 6 or 7, 10 or 11, 14 or 15) positions has been analysed by spectroscopic measurements. The dimeri…
With the help of bibliometric mapping techniques, we have developed a methodology of “self-organized” structuring of scientific fields. This methodology is applied to the field of neural network research. We propose a field-definition based on the present situation. This is done by letting the data themselves generate…
A series of conjugated porphyrin oligomers have been prepared and the evolution in their electronic properties is discussed; the crystal structure of the dimer is presented, as well as the MALDI TOF mass spectrum of the hexamer.