Materials Literature
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The ring-opening polymerization of a novel heterocyclic monomer of the 1,4-dioxane 2,5-dione type, namely 3-(1,2-3,4-tetraoxobutyldiisopropylidene)dioxane-2,5-dione (DIPAGYL), derived from glycolic acid and partially protected gluconic acid, was investigated. Polymerization of DIPAGYL was carried out in the presence o…
Solutions of Co(3)(dpa)(4)Cl(2), where dpa = di(2-pyridyl)amide ion, in CD(2)Cl(2) were studied by NMR in the temperature range 183-303 K. The spectra show only four (1)H and five (13)C resonance signals, consistent with the D(4) symmetry of the molecules found in the solid. The magnetic susceptibility in solution was…
The need to grow high quality semiconducting hydrogenated amorphous carbon (a-C:H) thin films to allow n-type electronic doping by nitrogenation has lead us to deposit films with low paramagnetic defect density (1017 cm−3). The films were grown on the earthed electrode of a radio frequency driven plasma enhanced chemi…
The aluminium alkoxide mediated ring-opening polymerization of (di)lactones offers a great versatility to the point where the main situations covered by the definition of living and controlled polymerizations can be illustrated. Furthermore, substitution of a coordination-insertion mechanism for the traditional anioni…
Abstract Summary: ModBase is a database of evaluated and annotated comparative protein structure models. The database also includes fold assignments and alignments on which the models were based. Availability: ModBase is accessible on the Web at http://guitar.rockefeller.edu/modbase. Models for yeast proteins are also…
Ferromagnetic and antiferromagnetic alternating interactions within and between chains, respectively, were interpreted for a one-dimensional coordination polymer having high-spin (S = 5/2) MnII centers bridged by azido ligands, namely, [Mn(bpm)(N3)2]n (bpm = bis(pyrazol-1-yl) methane).
The adsorption of the cationic dye rhodamine 3B in the clay hectorite is studied using electronic absorption and fluorescence emission spectroscopy. The results show the presence of various dye monomers, dimers, and higher aggregates and their interconversion subject to variations in loadings and stirring times. The g…
Oxidation of the non-mesomorphic ferrocene derivative 1 with silver toluene-4-sulfonate gave the ferrocenium derivative 2, which showed a monotropic columnar phase. The latter two-dimensional phase is composed of ribbons, in which derivative 2 is organized into bilayers, and has a centered rectangular symmetry with a…
Solutions of the poly(propylene imine) dendrimers DAB- dendr -(PA) 32 and DAB- dendr -(PA) 64 in methanol are investigated with small angle neutron scattering over the range of dendrimer mass fraction 0.01 ≤ x ≤ 0.80. The single particle scattering function, P ( q ), is used to calculate the structure factor, S ( q ),…
A density-functional theory for spherical particles interacting via an arbitrary soft pair potential is presented. The derivation is solely based on limits, where the behavior is exactly known, namely, a zero-dimensional cavity and the low-density virial expansion. The approach generalizes the fundamental-measure theo…
Measurements of the basal-plane resistivity ρ a ( T , H ) performed on highly oriented pyrolitic graphite, with magnetic field H ∥ c -axis in the temperature interval 2–300K and fields up to 8 T, provide evidence for the occurrence of both field-induced and zero-field superconducting instabilities. Additionally, magne…
Elastic-plastic rate-independent materials with isotropic hardening/softening of nonlocal nature are considered in the context of small displacements and strains. A suitable thermodynamic framework is envisaged as a basis of a nonlocal associative plasticity theory in which the plastic yielding laws comply with a (non…
Epoxidation of olefins by TiIV peroxo and hydroperoxo (alkylperoxo) complexes was investigated using a hybrid DFT method (B3LYP). Reaction energies and activation barriers for direct oxygen transfer to ethylene as a model olefin were computed for various model complexes to compare the epoxidation activity of Ti(η2-O2)…
High-field, multifrequency EPR data are presented for vanadium(III)-doped CsGa(SO4)2·12X2O, where X = D or H, which afford the direct determination of the spin-Hamiltonian parameters pertaining to the 3Ag (S6) ground term. A pronounced change in the g values and zero-field splitting is observed upon isotopic substitut…
The electrochemical growth of thick (∼2 mm) emeraldine, polyaniline ( PANI E ) films from solutions containing 2 M HBF 4 and 0.25 M aniline is demonstrated. Electrochemically and chemically prepared PANI E films, cast from formic acid solutions, are compared. The combination of electrochemical results with Fourier tra…
The crystallization of colloidal particles at an air-water interface is investigated by computer simulations. We numerically clarify the bond-orientational order parameter Phi(6) with different particle concentrations. In addition, the profiles of the pair-correlation function g(r), the orientational correlation funct…
The structural, electronic, and magnetic properties of the highly mismatched perovskite oxides, ${\mathrm{Th}}_{0.35}{A}_{0.65}{\mathrm{MnO}}_{3},$ where A is for the alkaline earth divalent cations (Ca, Ba, Sr), which are all characterized by the same large tolerance factor $(t=0.934),$ have been investigated by usin…
We report the preparation, absorption spectra, and photophysical properties (fluorescence spectrum, quantum yield, and lifetime) of five dendrimers of the poly(propylene amine) family (POPAMs) functionalized with dansyl units at the periphery. Each dendrimer n D, where n = 1 to 5 is the generation number, comprises 2…
A new strategy for the fabrication of wire/sheath nanocableswith an inner diameter as small as 6 nm is presented. Under the right conditions organic monomers with polar groups can self-organize into cylindrical supramolecules as shown in the Figure. After γ-irradiation, polymerization occurs to form polymer tubules, i…
We report the results of a systematic study on the temperature dependence of the normal state conductivity, measured along the a, b', and c* axis, in a representative set of Bechgaard salts.The anisotropic electron transport of four compounds are compared: (TMTSF)zC104, (TMTSF)zPF6, (TMTTF),Br and (TMTTF)2PF6.We analy…