Materials Literature
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The monobutyl ester of H8DOTP, the ligand H4DOTPMB, was synthesized, and the protonation constants (KHi) and the stability constant of Gd(DOTPMB) were determined by pH-potentiometry (25 °C, 0.1 M Me4NCl): logKHi, (i = 1, 2, and 3) = 10.34(0.02), 7.72(0.025), and 2.42(0.030), respectively, and logKGdL = 12.19(0.05). Th…
An antimony-substituted polyoxomolybdate, [PSbIII(H2O)Mo11O39]4−, of the α-Keggin structure, has been synthesized. Although the molecular structure is typical, we have found from the analysis of the X-ray diffraction data that the crystal is anisotropic with alignment of the molecular units so that the substituted ant…
Diamond nucleation by biased hot filament chemical vapor deposition was investigated by scanning electron microscopy and atomic force microscopy. It was found that a number of microdefects were produced on a substrate surface owing to energetic ion bombardment under negative substrate bias, which increased with increa…
Microporous dodecahedral aggregates of a polyoxotungstate were synthesized by homogeneous precipitation from aqueous solution using hydrolysis of urea at 373 K (H 3 PW 12 O 40 + 3 / 2 (NH 2 ) 2 CO + 3 / 2 H 2 O → (NH 4 ) 3 PW 12 O 40 ↓ + 3 / 2 CO 2 ). The aggregates isolated after various reaction periods were charact…
Two polymorphous compounds with the general formula [Cu(NCS)2(dpk·CH3OH)]n (dpk = di-2-pyridyl-ketone) have been synthesised and have been characterised both structurally and magnetically. The dpk·CH3OH ligand is the result of the metal-promoted solvolysis of dpk in methanol and acts as a neutral donor. X-ray analysis…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTGrowth of Ionic Crystals in Carbon NanotubesMark Wilson and Paul A. MaddenView Author Information Physical and Theoretical Chemistry Laboratory Oxford University, South Parks Road, Oxford OX1 3QZ, U.K. Cite this: J. Am. Chem. Soc. 2001, 123, 9, 2101–2102Publication Dat…
We present the crystal structure of pcFe(4-methylpiperidine)2 as a first example of a low-spin iron(II) phthalocyanine (pc) complex bis-axially coordinated by aliphatic amines. It is shown that electronic rather than steric effects are responsible for the elongation of the Fe−N(axial) bond in pcFeL2 complexes. Using d…
Up to eight redox-active ferrocenyl units have been incorporated, through the unsaturated ethynyl linkers, on the periphery of a series of cyclic tetrapyrrole derivatives including zinc(II) phthalocyanine and 2,3-naphthalocyanine, and nickel(II) meso-diphenylporphyrin. The synthesis of the former two macrocycles 4 and…
Crackling noise arises when a system responds to changing external conditions through discrete, impulsive events spanning a broad range of sizes. A wide variety of physical systems exhibiting crackling noise have been studied, from earthquakes on faults to paper crumpling. Because these systems exhibit regular behavio…
The competitions between ferroelectric and rotational instabilities in rhombohedral ${\mathrm{PbZr}}_{x}{\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{O}}_{3}$ near $x=0.5$ are investigated using first-principles density-functional supercell calculations. As expected, we find a strong ferroelectric instability. However, we…
Correlation between orbital structure and magnetic ordering in layered manganites is examined. A level separation between the ${3d}_{{3z}^{2}\ensuremath{-}{r}^{2}}$ and ${3d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ orbitals in a Mn ion is calculated in the ionic model for a large number of the compounds. It is found that the…
The results of electrical resistance (1.4 - 300 K), magnetization (2-300 K) and heat-capacity (2 - 50 K) measurements in Y$_2$PdGe$_3$, found to crystallize in a AlB$_2$-derived hexagonalstructure, are reported. The results establish that this compound is superconducting below 3 K. This obervation is interesting consi…
Uniform iron−molybdenum nanoparticles were prepared by thermal decomposition of metal carbonyl complexes using a mixture of long-chain carboxylic acid and long-chain amine as protective agents. The sizes of the nanoparticles can be systematically varied from 3 to 14 nm by changing the experimental conditions. High-res…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTCarbon Nanotubes as Superior Sorbent for Dioxin RemovalRichard Q. Long and Ralph T. YangView Author Information Department of Chemical Engineering University of Michigan Ann Arbor, Michigan 48109-2136 Cite this: J. Am. Chem. Soc. 2001, 123, 9, 2058–2059Publication Date…
The thermal conductivity and heat capacity of Pb modified Ge–Se glasses, Pb20GexSe80−x (x=17–24) and PbyGe42−ySe58 (y=0–20), which exhibit carrier-type reversal from p type to n type at specific compositions, have been measured simultaneously by the photopyroelectric technique. The thermal conductivity as well as the…
We study quantum fluctuation effects on light absorption spectra of one-dimensional (1D) interacting electron systems in the framework of the 1D extended Hubbard model. Our targets are halogen-bridged (HB) Ni(Ni-Br) complex and ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3},$ which are typical 1D spin-density-wave or antiferrom…
The CaS:Pb phosphor emitting blue electroluminescence (EL) induced by dimeric Pb2+ luminescent centers was deposited using the controlled atomic layer deposition technique. The effect of the incorporation method and concentration of Pb2+ ions on the color of high luminance CaS:Pb phosphor was investigated at the depos…
We describe the direct observation of surface states on individual CdSe quantum dots by conductive scanning force spectroscopy at room temperature and the dependence of these states on size quantization and humidity conditions. Peaks corresponding to surface states that lie within the gap appear at both voltage polari…
The interactions between nanoparticles coated by end-grafted homopolymers of comparable size are studied using Edwards' self-consistent field (SCF) theory. The equilibrium monomer density distribution is obtained by solving the SCF equations in bispherical coordinates. It is shown that, because of the spherical geomet…
Copper tetraazaporphyrin is used as a model for copper phthalocyanine in theoretical simulations of the features observed at the Cu ${L}_{2,3}$ near-edge x-ray absorption spectra. Theoretical results obtained by a density-functional theory approach provided interpretations of the different features observed experiment…