Materials Literature
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The solubility of pyridine-4-carbohydrazide (isoniazid) in ethanol, methanol, ethyl acetate, and acetone has been measured gravimetrically at various temperatures ranging from (301 to 313) K at atmospheric pressure. Isoniazid is most soluble in methanol, followed by acetone, ethanol, and ethyl acetate at a temperature…
A semiquantitative mean-field model for the thermally induced (heating-induced) polymer coil-to-globule transition (HCGT) is developed with no adjustable parameters. The transition temperature Θ is given for a long chain by the equation Θ = 2 T p * [1 − ρ̃ B (Θ)], where T p * is the characteristic temperature of the p…
The synthesis and characterization of a new sapphyrin analogue, dioxabenzosapphyrin, are reported. The benzodifuran moiety upon which this system is based leads to the incorporation of two oxygen atoms within the central macrocyclic core, thus replacing two protonated nitrogen centers found in normal pentaaza sapphyri…
Cadmium sulfide (CdS) quantum dots (QDs) grafted with thermoresponsive poly( N-isopropylacrylamide) chains have been prepared. As the temperature increases, PNIPAM chains shrink and aggregate so that the QDs exhibit enhanced fluorescence emission. At a temperature around the lower critical solution temperature (LCST)…
Hyperbranched polyethers having poly(ethylene glycol) (PEG) segments at their molecular periphery were prepared by a simple procedure wherein an AB 2 type monomer was melt-polycondensed with an A-type monomer, namely, heptaethylene glycol monomethyl ether. The presence of a large number of PEG units at the termini ren…
Symmetric poly(ethylene oxide- b -styrene- b -isoprene- b -styrene- b -ethylene oxide) (OSISO) pentablock terpolymers with narrow molecular weight distributions in all blocks were synthesized by anionic polymerization. These OSISO pentablock terpolymers have a common poly(styrene- b -isoprene- b -styrene) (SIS) core c…
Facile photochemical exocyclic [2 + 2 + 2] cycloaddition produced a series of electron-donating 1,1'-bi(isobenzofuran)s having various aryl groups at the 3,3' positions. The 1,1'-bi(isobenzofuran) skeleton with a highly coplanar structure is a useful building unit to construct the narrow bandgap pi-conjugated systems…
The binding dynamics of the guests acenaphthene, phenanthrene, fluorene, and acenaphthenol with sodium cholate aggregates were studied using laser flash photolysis and fluorescence. The location of the guests in the bile salt aggregate is determined by the guest's hydrophobicity, where acenaphthene, phenanthrene, and…
High-quality single-walled carbon nanotubes (SWNT) with high yield were produced by using small-pore Co-MCM-41 catalyst, templated by a C10 surfactant and containing 3 wt % Co. A complete incorporation of Co ions in the silica matrix without formation of surface Co oxides and the contact time of the reaction, in the c…
Zinc sulfide (ZnS) is an important functional material for electronics and optoelectronics. In this paper, heteroepitaxial growth of ZnS nanowire arrays on Zn 3 P 2 crystals, which are structural uniform with preferred (0001) growth directions, was fulfilled by using a simple thermal evaporation method. Studies found…
New methodology is described for the synthesis of porphyrins bearing four (A 4, cis-A 2B 2, cis-ABC 2, trans-A 2B 2) or fewer (A, cis-AB, cis-A 2, trans-A 2) meso substituents. The method entails condensation of two 1-acyldipyrromethanes in the presence of a metal salt (MgBr 2, 3 mol equiv) and a noncoordinating base…
Abstract The coordination of carboxylate capping agents on silver and gold nanoparticles is investigated by Fourier transform infrared spectroscopy (FTIR). The shift of carboxylate stretching frequency confirmed that carboxylate bound on gold nanoparticle forms unidentate coordination, while that on silver nanoparticl…
Spatial distribution of surface enhanced Raman activity is visualized for two-dimensional (2D) nearly close-packed and well-ordered monolayer array of gold nanoparticles by using scanning near-field optical microscope. The 2D arrays exhibit highly nonuniform enhancement in Raman scattering, i.e., the regions along the…
We describe the preparation of inclusion complexes composed of amylose and strongly hydrophobic polyesters in a parallel enzymatic polymerization system. This was achieved by carrying out phosphorylase-catalyzed enzymatic polymerization of α- d -glucose 1-phosphate from maltoheptaose, giving rise to amylose as a host,…
Reported solution-processed field-effect transistor (FET) devices based on single-walled carbon nanotube (SWNT) networks have either high mobility but low on/off ratio or vice versa. Recently, Arnold et al. ( Nat. Nanotechnol. 2006, 1, 60−65) have made significant improvements in obtaining semiconductor-enriched SWNTs…
A quantitative structure−property relationship (QSPR) study was performed to develop a model for prediction of the lower flammability limit (LFL) of pure compounds. The obtained model is a four-parameter multilinear equation. These four parameters are calculated from the chemical structure of every molecule. The avera…
The relationship between stabilities and shape configurations of carbon and boron nitride (BN) nanographenes (NGs) was studied at the B3LYP/6-31G* level of theory. The HOMO−LUMO energy gaps of rectangular-shaped carbon nanographenes (CNGs) decrease as the graphene sizes increase with a direct inverse dependence on the…
We have measured the Young’s modulus and thickness of ultrathin polyelectrolyte multilayer (PEM), polystyrene (PS), and poly(methyl methacrylate) (PMMA) films as a function of relative humidity. We demonstrate that PEMs undergo substantial swelling and plasticization in the presence of ambient water and that both the…
A photochemical active triangle terarylene was synthesized and the photochromic behavior was investigated. Its photochromic reactivity can be strongly suppressed by selected oxidization of the sulfur atoms in the molecules. Reactivated photochromic reactivity was obtained by deoxidization of the S, S-dioxide moieties.…
The 2:2 complex of Co-carbene is generated by photolysis of [Co(hfpip)2(D2py2(TBA))]2, 1, having a cyclic structure functioning as a single-molecule magnet with Ueff = 96 K and Hc = 10 kOe at 1.9 K after annealing at 70 K.