Materials Literature
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The influence of substituents with increasing steric demands on the structure of nickel(II) 5,15-disubstituted porphyrins has been investigated with X-ray crystallography, UV−visible absorption spectroscopy, resonance Raman spectroscopy, molecular energy optimization calculations, and INDO/s molecular orbital calculat…
A modular building-block approach has been developed for the construction of linear amphipathic porphyrin arrays. The reaction of meso-(trifluoromethyl)dipyrromethane and an aldehyde under the conditions of the two-step room temperature porphyrin synthesis affords the trans-substituted porphyrin (13-56% yields). A sim…
The synthesis and thermal evolution of new hydrotalcite-type (HT) anionic clays containing rhodium or ruthenium are investigated in order to obtain catalysts containing well dispersed and stable noble-metal particles, active, for example, in the partial oxidation of methane to synthesis gas.
Two-dimensional arrays of 1000 Å silver particles were prepared by adsorption from colloidal suspensions onto glass slides derivatized with (3-mercaptopropyl)trimethoxysilane. By variation of the concentration of the colloidal suspensions, slides with different interparticle distances were obtained, and their extincti…
Rhodium in nanosize (1−3 nm) was prepared by vapor deposition of Rh on a well-ordered TiO 2 (110)1 × 2 single crystal. The morphology and the sizes of Rh had been determined by scanning tunneling microscopy in ultrahigh vacuum. The adsorption of CO at 300 K induces the disruption of Rh crystallites as indicated by a d…
Cobalt(II) hexacyanoferrate(III,II), a system analogous to prussian blue, is a unique electrochromic material: its color is not only dependent on the oxidation potential, but also on the nature of the countercations sorbed from electrolyte during reduction. The electrodeposition of cobalt hexacyanoferrate thin films,…
These experiments assessed and quantitated the release of free manganese Mn++ from the hepatobiliary contrast agent Mn-DPDP (manganese dipyridoxal diphosphate), using several magnetic resonance techniques (EPR spectroscopy, 31P-NMR spectroscopy, and relaxometry) to differentiate between free Mn++ and Mn++ in complexes…
The structure of cubic ZrP(2)O(7) at room temperature has been solved and refined using a combination of modeling and high-resolution neutron powder diffraction data. The cell edge is 24.74 Å, the space group is Pa&thremacr;, and Z is 108. For those P(2)O(7) units not on a 3-fold axis, the P-O-P angles range from 134…
Attempts to discover molecular chromophores with large hyperpolarizabilities have largely focused on closed-shell organic species. This contribution explores the use of sum over states (SOS) perturbation theory and the computationally efficient intermediate neglect of differential overlap (INDO) model Hamiltonian, com…
In the present paper, we report an unprecedented selectivity in the products during singlet oxygen mediated oxidation of olefins included within dye-exchanged X and Y zeolites. Singlet oxygen is generated within a zeolite by irradiating a thiazine dye exchanged into zeolites. Oxazine and thiazine dye molecules can be…
Au-dispersed TiO2(anatase) thin films have been prepared by a novel method, liquid-phase deposition (LPD). The deposited films were characterized by XRD, XPS, TEM and UV–VIS absorption spectroscopy. The results showed that the titanium oxide thin film containing AuIII ions was formed from a mixed solution of ammonium…
Monolithic and transparent gels were prepared by mixing various ethoxide silicon precursors containing Si—CH3 and Si—H groups, the composition ensuring the same number of C—H and Si—H bonds. Pyrolysis of these samples was followed under helium flow by connecting thermogravimetry, gas chromatographic and mass spectrome…
We numerically analyze mesh entanglements in model polymer networks. We find G-${\mathit{G}}_{\mathit{ph}}$\ensuremath{\approxeq}0.85${\mathrm{\ensuremath{\rho}}}_{\mathit{ent}}$${\mathit{k}}_{\mathit{BT}}$, where ${\mathrm{\ensuremath{\rho}}}_{\mathit{ent}}$ is the entanglement density, G the shear modulus which was…
Hydrotalcite-like compounds containing Mg(II) and Cr(III) or Ni(II) and Cr(III) cations in the brucite-like layers have been synthesized by the coprecipitation method. The layered structure has been confirmed by Powder X-ray diffraction, and characterization has been completed by elemental chemical analysis, FT-IR and…
In this paper we report a comparative experimental thermochemical and ab initio quantum chemical study of metal−ligand bonding and bonding energetics in the group 3, lanthanide, group 4, and group 5 zerovalent bis(arene) sandwich complexes Sc(TTB) 2 ( 1 ) Y(TTB) 2 ( 2 ), Gd(TTB) 2 ( 3 ), Dy(TTB) 2 ( 4 ), Ho(TTB) 2 ( 5…
The heterobimetallic one-dimensional arrays {(DMF) 4 EuNi(CN) 4 } ∞ and {(DMF) 4 EuPt(CN) 4 } ∞ were prepared from the metathesis of (NH 3 ) x EuCl 2 with K 2 Ni(CN) 4 and K 2 Pt(CN) 4, respectively, in DMF. The analogous reaction between (NH 3 ) x YbCl 2 and K 2 Ni(CN) 4 in DMF or DMA resulted in oxidation of Yb 2+ a…
The performance of several different two-dimensional NMR methods for the measurement of carbon−proton dipolar couplings in liquid crystalline phases is analyzed. Proton-detected local field spectroscopy allows the measurements of short range C−H couplings, which correspond to directly bond pairs, by direct inspection…
Contact-angle measurements, the ASTM standard wetting test for polyolefin films, and X-ray photoelectron spectroscopy (XPS or ESCA) were used to characterize flame-treated polypropylene (PP) films. Two combustion models, STANJAN and PREMIX, were then used to determine the chemical and physical properties of the flames…
Fumarase C catalyzes the stereospecific interconversion of fumarate to L-malate as part of the metabolic citric acid or Kreb's cycle. The recent three-dimensional structure of fumarase C from Escherichia coli has identified a binding site for anions which is generated by side chains from three of the four subunits wit…
The electrochemical properties of poly(3,4-ethylenedioxythiophene) are studied using the bending beam method to detect volume changes during electrochemical transformations of the material. Thin films of poly(3,4-ethylenedioxythiophene) immersed in different supporting electrolytes first contract very rapidly and then…