Materials Literature
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From dielectric relaxation and equation-of-state measurements on polymethylphenylsiloxane and polymethyltolylsiloxane, the relative contributions of volume and thermal energy to the temperature dependence of the segmental relaxation times are quantified. In both polymers, volume exerts a substantial effect, being almo…
The synthesis of linear multiporphyrin arrays with mono- and bisphosphine-substituted porphyrins as ligand donors and ruthenium(II) or rhodium(III) porphyrins as ligand acceptors is described. With appropriate amounts of the building blocks mixed, linear dimeric and trimeric arrays have been synthesized and analyzed b…
Mo K-edge XAFS spectra have been measured for ordered mesoporous silica MCM-41 grafted with the complexes [MoO2X2(thf)2] (X=Cl, Br). For grafting reactions in the absence of triethylamine, materials with 1 wt. % Mo are obtained; the Mo K-edge EXAFS results indicate the co-existence of isolated surface-fixed monomeric…
A highly birefringent, luminescent chiral nematic liquid crystal is shown to have an extremely broad photonic stop band (see dashed line in Figure) overlapping its emission spectrum. Highly circularly polarized photoluminescence is observed from the liquid crystal itself and from an indirectly excited dye dopant. The…
Periodic density functional calculations using pseudopotentials and a local basis set were performed on the type I clathrates A(8)Ga(16)Ge(30) (A=Sr, Ba). Both are known to show promising thermoelectric properties. Ab initio wave functions were analyzed within the framework of the quantum theory of atoms in molecules.…
Reduction of the dielectric constant k to the ultra low‐ k range is important for the continuing miniaturization of semiconductor devices. It is demonstrated that γ‐cyclodextrin can act as an effective porogen (see Figure) to reduce k while maintaining good film strength. A continuous thin pure‐silica zeolite MFI film…
A family of five metallodendrimers with pentamethylamidoferrocenyl termini were synthesized from the DSM dendrimers G(n)-DAB-dend-(NH(2))(x) (x=4, 8, 16, 32, 64) and characterized by standard techniques, including prominent molecular peaks (broad for x=64) in their MALDI-TOF mass spectra. Oxidation of G(4)-DAB-dend-(N…
The mixed-ligand complexes [Co(III)(tpy)(Cat-N-SQ)]Y and [Ni(II)(tpy)(Cat-N-BQ)]PF(6) (tpy = 2,2':6',2' '-terpyridine; Cat-N-BQ, Cat-N-SQ = mononegative and radical dinegative Schiff base diquinone ligand; Y = PF(6), BPh(4)) were prepared. Structural and spectroscopic data support the different charge distribution of…
Electrochemical coating of individual single‐walled carbon nanotubes (SWCNTs) with thin films obtained via oxidative coupling of an amine or reductive coupling of an aromatic diazonium salt is reported. The same SWCNTs have been characterized before and after modification by electrical transport measurements and confo…
Vanadium oxide hydrate has been used in a new, robust, and inexpensive shape‐templating synthesis leading to silica nanotubes (SiO 2 ‐NTs, see Figure) with good chemical purity, a well‐defined morphology, and high aspect ratio. Unidimensional nanosized cavities or channels are made accessible through the open ends of…
In this paper, we report on in situ optical/electrochemical investigations using a combination of surface plasmon resonance spectroscopy and electrochemistry in order to determine the complex dielectric constants of poly(3,4-ethylenedioxythiophene) (PEDOT) thin films. The PEDOT films were deposited by in situ electrop…
The perovskite-related crystal structure of the compound Sr 0.7 Y 0.3 CoO 2.62 was determined and refined using synchrotron X-ray and neutron powder diffraction, in space group I 4/ mmm, a = 7.6237(8) Å and c = 15.314(2) Å, to R I = 0.041 in the synchrotron data set. It contains layers of CoO 6 octahedra, perpendicula…
Tailored optical properties have been imparted to polystyrene (PS) colloids of various sizes by the layer-by-layer (LbL) assembly of silica-coated gold (Au@SiO 2 ) or silica-coated silver (Ag@SiO 2 ) nanoparticles with different shell thicknesses and an electrostatically bridging polyelectrolyte, poly(diallyldimethyla…
Highly ordered cobalt substituted MCM-41 samples were synthesized and characterized for application as catalytic templates for producing aligned single walled carbon nanotubes (SWNT). Highly reproducible Co−MCM-41 samples were successfully synthesized using alkyl templates with 10, 12, 14, 16, and 18 carbon chain leng…
A novel donor-acceptor bisphthalocyanine (bis-Pc, 1) in which two different Pc units (Zn(II)-Pc and Ni(II)-Pc) are linked via vinylene spacers to the pseudopara positions of a central [2.2]paracyclophane moiety is described. The synthesis of 1 is achieved by two successive Heck reactions of pseudopara-divinyl[2.2]para…
There is recently interests in the ``left-handed '' materials. In these materials the direction of the wave vector of electromagnetic radiation is opposite to the direction of the energy flow. We present simple arguments that suggests that magnetic composites can also be left-handed materials. However, the physics inv…
Organic monolayer-passivated Group III−V dilute magnetic semiconductor (DMS) Mn x In 1 - x As nanocrystals, ranging from 2.2 to 10 nm in diameter, were synthesized by high-temperature colloidal arrested precipitation using the dehalosilylation of InCl 3 and MnBr 2 with tristrimethylsilylarsine in the coordinating solv…
The effect of substrate surface energy on transcrystalline growth at the interface of a semicrystalline polymer and its effect on interfacial adhesion were investigated for substrates treated with various silane coupling agents. A thin film of isotactic polypropylene (iPP) crystallized on a high surface energy substra…
The magnetism of a series of tetranuclear complexes of the [Fe4IIL4]8+ [2x2]-grid-type was investigated, revealing the occurrence of spin transition behavior within this class of compounds. The phenomenon depends directly on the nature of the substituent R(1) in the 2-position on the central pyrimidine group of the li…
Soluble crosslinked macromolecules (microgels) used as stabilizers of catalytically active metal nanoclusters allow control of the nanocluster size by simply changing the crosslinking degree of the microgel. Microgel‐stabilized metal nanoclusters are easily prepared and stored in the solid state, and those of Pd (see…