Materials Literature
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Tetrakisarylporphyrins are conveniently chlorosulphonated in high yields.These chlorosulphonyl compounds may he converted in high yield into sulphonic acid derivatives through reaction with a variety of nucleophiles so as to give, for example, the free sulphonic acid, a sulphonamide or a sulphonate ester.
The silylation of borosilicate with APTS ((γ-aminopropyl)triethoxysilane) is studied as a tool to improve zeolite incorporation in PI (polyimide) films. Among other experimental parameters, a quantification of the zeolite outer surface silanols is performed in order to determine the most appropriate silylation conditi…
High-resolution electron microscopy (HREM), combined with digital image processing and computer simulation techniques, has been used to carry out a microstructural characterization of some Rh/TiO2 catalysts reduced at 473, 773 or 823 K. A sample resulting from the reduction of the catalyst at 773 K, reoxidized with fl…
Silica pillared Ca 2 Nb 3 O 10 was prepared from the layered perovskite KCa 2 Nb 3 O 10 via alkylammonium ion intercalated Ca 2 Nb 3 O 10 . The obtained materials were characterized by XRD, TEM, NMR, and BET measurements. The interlayer spacing increased in parallel with the length of the alkyl chain of intercalated a…
The driving force behind the research on advanced materials has largely been aerospace and defense applications. In such applications the customer-induced limitations and infrastructural economic factors are secondary to the application-oriented parameters. Automobiles, on the other hand, represent the primary consume…
The incorporation of divalent cations (Mg2+, Mn2+, Cu2+, Sr2+, Cd2+, Ba2+ and Pb2+) in vaterite and calcite has been studied by atomic absorption spectroscopy (AAS), optical and scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) spectroscopy. The samples of vaterite a…
Adsorption of HCl, HBr, NO and SO 3 on nanoscale MgO (autoclave prepared = AP-MgO) and microscale MgO (conventionally prepared = CP-MgO) has been studied. The higher surface area of AP-MgO allows a higher capacity of these gases to be adsorbed/mol MgO. However, at pressures of 100 Torr or higher, the amounts adsorbed/…
Abstract Construction of dendritic macromolecules based on the mimicry of macroscopic branching patterns found in trees is reviewed. From this mimicry, synthetic strategies have been developed for the preparation of precise macromolecular building blocks referred to as Starburstr̀/Cascade dendrimers. These dendrimer c…
High-impact-modified polystyrene (HIPS) is made by thermal or radical polymerization of styrene containing dissolved polybutadiene (PB). The reaction leads, intermediately, to blends of yet ungrafted PB, of the homopolymer PS, and of graft copolymers PBgS varying in the number of PS grafts per PB chain. The polymeriza…
This paper presents a general overview of calcification and involves aspects of the chemical, physical, and biological nature of mineral crystals in invertebrate and vertebrate tissues, with selected examples of the latter. Two broad areas are described: mineral structure and composition. Mineral formation is detailed…
Eight tris(organotin)-substituted Keggin tungstosilicate heteropolyanions have been synthesized and characterized by elemental analysis, infrared and Mössbauer spectroscopy, multinuclear NMR, and X-ray crystallography. The new anions contain alpha- or beta-SiW(9)O(34)(10)(-) moieties and are of two structural types, […
Transient absorption measurements with subpicosecond resolution have been performed on nickel(II) dodecaphenylporphyrin (NiDPP), a highly nonplanar tetrapyrrole. Following photoexcitation, NiDPP deactivates by the pathway (π,π*) → (d,d) → ground state, the route proposed previously for planar analogues. However, the (…
This communication describes the synthesis of a novel low band gap hydrocarbon polymer, poly(indenofluorene), PIF, composed of 3,9-di- tert -butylindeno[1,2- b ]fluorene building blocks. The polymer, with high degrees of polymerization (DP > 20), was generated by coupling alkylated 6,6,12,12-tetrachloro-6,12-dihydroin…
In this paper, the high chemical activity of the newly synthesized nanosize carbon spheres is demonstrated. The carbon spheres can be accreted by a treatment in acetone. The mechanism for the accretion is attributed to the combination of the hydrogen and oxygen atoms belonging to the acetone molecules with the adsorbe…
Hydrotalcite-like compounds (HTLCs), which are also called anionic clay minerals or Layered Double Hydroxides (LDHs), can be formulated by M(II) 1−x M(III) X (OH) 2 (A n− ) X/n yH 2 O. This chemical, which has anoin exchange capacity, could be an alternative chemical for phosphorus removal. The phosphate uptake by HTL…
A phenylethynyl terminated imide (PETI) oligomer from the reaction of 3,3',4,4'-biphenyltetracarboxylic dianhydride, an 85:15 molar ratio of 3,4'-oxydianiline and 1,3-bis(3-aminophenoxy)benzene and 4-phenylethynylphthalic anhydride as the end-capper at a theoretical number average molecular weight (Mn) of - 5,000 g/mo…
New molecules with dimesitylboron as the acceptor group and bithiophene as the unsaturated chain have been synthesized and their non-linear optical properties investigated. The theoretical first hyperpolarizabilities determined by calculations are compared with experimental results.
Four crystal structures of the title complexes have been analyzed by X-ray crystallography. 1: C 80 H 68 N 17 Nd, a = 17.0545(6) Å, c = 22.807(3) Å, tetragonal, P 4/ ncc, Z = 4. 2: C 80 H 68 N 17 Gd, a = 17.399(8) Å, c = 11.377(6) Å, tetragonal, P 42 1 2, Z = 2. 3: C 80 H 70 N 17 OHo, a = 18.096(5) Å, c = 11.079(6) Å,…
The breakdown of benzene, ethylbenzene, styrene, and o -chlorotoluene in aqueous solution by 520 kHz ultrasonic waves was studied at various initial concentrations in the millimolar range. First-order reaction rates depend upon both initial concentration and sonication time. These variations can be explained by a mode…
Thin films of monophasic crystalline hexagonal ZnO were deposited from solutions of zinc acetate in presence of ethane-1,2-diamine and sodium hydroxide onto glass microscope slides and tin oxide coated glass. At least two distinct morphologies of ZnO were observed, depending on the deposition conditions, by scanning e…