BRIDGED POLYCYCLIC AROMATIC HYDROCARBONS. A REVIEW
(1997). BRIDGED POLYCYCLIC AROMATIC HYDROCARBONS. A REVIEW. Organic Preparations and Procedures International: Vol. 29, No. 3, pp. 243-283.
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Synthesis and properties of polyimides derived from 1,4-Bis(4-Aminophenoxy)2,5-di-tert-Butylbenzene
Novel aromatic polyimides containing symmetric, bulky di-tert-butyl substituents unit were synthesized from 1,4-bis(4-aminophenoxy)2,5-di-tert-butylbenzene (BADTB) and various aromatic tetracarboxylic dianhydrides by the conventional two-stage procedure that included ring-opening polyaddition in a polar solvent such a…
Quasi-Elastic Light Scattering Study of Highly Swollen Lamellar and “Sponge" Phases
We investigate experimentally, using quasi–elastic light scattering the dynamical properties of highly swollen lamellar and “sponge" phases. In our system the structural sizes – smectic period for lamellar phases or characteristic cell size for “sponge" phases – may be changed continuously by adding solvent up to scal…
Magnetization and conductivity forLa1−xSrxMnO3-type crystals
We use a model previously formulated based on the double-exchange mechanism and diagonal disorder to calculate magnetization and conductivity for ${\mathrm{La}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Sr}}_{\mathrm{x}}$${\mathrm{MnO}}_{3}$-type crystals as a function of temperature. We use the results of the mo…
Cloning, sequencing, and overexpression of the Anaerobiospirillum succiniciproducens phosphoenolpyruvate carboxykinase (pckA) gene
The phosphoenolpyruvate (PEP) carboxykinase-encoding gene from the anaerobic, CO2-fixing, succinate-producing bacterium Anaerobiospirillum succiniciproducens was cloned, sequenced, and expressed in Escherichia coli. The gene encoded a 532-residue polypeptide with a calculated molecular mass of 58.7 kDa. The sequence o…
Synthesis and magnetic properties of novel compounds R3(Fe, T)29 (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy; T=V and Cr)
A systematic investigation of structure and intrinsic magnetic properties of the novel compounds R3(Fe, T)29 (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy; T=V and Cr) has been performed. The lattice constants and unit cell volume decrease with increasing the rare-earth atomic number from R=Nd to Dy, except for Ce, reflecting the…
Phase Behavior of Isotactic Polypropylene−Poly(ethylene/ethylethylene) Random Copolymer Blends
The melt-state phase behavior of isotactic polypropylene (i-PP) blended with a series of poly(ethylene/ethylethylene) random copolymers has been investigated using small-angle neutron scattering (SANS). These PEE xx copolymers, where xx is the percentage of ethylethylene (EE) units, were prepared by hydrogenation of a…
The Luminescence of Mn2 + ‐Activated ZnGa2 O 4
The luminescence of and doped with divalent manganese was studied by performing excitation, emission, and decay time measurements in the temperature range from 4.2 to 500 K. From the results of these measurements the following mechanism can be proposed. Excitation into the gallate host lattice leads to the formation o…
Water-Soluble Neutral Calix[4]arene−Lanthanide Complexes: Synthesis and Luminescence Properties
Water-soluble calix[4]arenes 10a,b with chromophores ("antenna") attached to the lower rim via a short spacer are described. In the neutral lanthanide complexes of 10a,b photoexcitation of the antenna induces lanthanide emission via intramolecular energy transfer. Calix[4]arene 10b with a chrysene moiety as sensitizer…
Bulk polymerization of lactides initiated by aluminium isopropoxide, 2. Beneficial effect of lewis bases and transfer agents
Abstract A high increase in the bulk polymerization rate of L,L‐lactide and racemic D,L‐lactide is observed when aluminium isopropoxide is added with an equimolar amount of a Lewis base, such as triphenylphosphine (P(ϕ) 3 ) and better 4‐picoline (C 6 H 7 N). Polylactide of high molecular weight and narrow molecular we…
Evolution of Switching Characteristics from Tristable to V-Shaped in an Apparently Antiferroelectric Liquid Crystal
We have identified three smectic phases, smectic A, ferrielectric and antiferroelectric, in a free-standing film of the first component compound of the mixture which was reported to show the V-shaped switching usable for realizing attractive displays [Inui et al. .: J. Mater. Chem. 6 (1996) 671]. The switching in the…
Electronic Structure, Porphyrin Core Distortion, and Fluxional Behavior of Bis-Ligated Low-Spin Iron(II) Porphyrinates
Three axially bis-ligated Fe(II) porphyrinates, [PFeL 2 ], have been investigated by Mössbauer spectroscopy over the temperature range 4.2−230 K and in an applied field of 6 T. Relatively large differences in the quadrupole splitting Δ E Q were found among [TMPFe(2-MeImH) 2 ] ( 1 ), [TMPFe( N -MeIm) 2 ] ( 2 ), and [OE…
Phase Behavior of Ternary Homopolymer/Diblock Blends: Microphase Unbinding in the Symmetric System
We consider the phase behavior of a symmetric AB diblock, blended with corresponding A and B homopolymers, all of equal chain length. Evaluating the phase diagram in mean-field theory at all compositions of the ternary blend, we find no hexagonal and cubic phases. However, up to three distinct lamellar phases can coex…
Preparation and Probable Structure of Layered Complexes of Vanadyl Phosphate with 1-Alkanols and 1,ω-Alkanediols
The direct reaction of liquid (or melted solid) 1-alkanols or 1,omega-alkanediols with solid finely ground VOPO(4). 2H(2)O in a microwave field leads to layered complexes of the composition VOPO(4).2C(n)()H(2)(n)()(+1)OH (n = 1-18) or VOPO(4).C(n)()H(2)(n)()(OH)(2) (n = 2-10), respectively. The results of X-ray diffra…
“Link-Functionalized” Polymers: An Unusual Macromolecular Architecture through Bifunctional Initiation
Bimetallic complexes of the type (C 5 Me 5 ) 2 Sm−R−Sm(C 5 Me 5 ) 2 were used for the living bis-initiated polymerization of methyl methacrylate and ε-caprolactone, giving polymers with discrete functionalities at the center of the backbone (“link-functionalized”). Poly(methyl methacrylate) containing olefin units was…
Synthesis of CdS Nanoparticles in Solution and in a Polyphosphazene Matrix
The synthesis and characterization of a polymer composite system containing quantum-confined II−VI semiconductor particles entrapped in a polyphosphazene network is discussed. A hybrid material was constructed using a guest:host approach in which the ion transporting ability of [NP(OCH 2 CH 2 OCH 2 CH 2 OCH 3 ) 2 ] n…
Fast chemical sensing with metal-insulator silicon carbide structures
It is demonstrated that the current-voltage characteristics of platinum-thin insulator silicon carbide diodes react rapidly to changes of the concentration of oxygen and hydrocarbons in the ambient already at temperatures around 500/spl deg/C-600/spl deg/C. In this letter, we use moving gas outlets to, for the first t…
Spin Delocalization in the Copper(I) Complexes of Bis(verdazyl) Diradicals
1,1‘,5,5‘-tetramethyl-6,6‘-dioxobis(verdazyl) (BVD) reacts with copper(I) halides in acetonitrile and copper(II) halides in methanol to give copper(I) coordination polymers of composition [Cu 2 X 2 (BVD)] x . When X = Cl and X = Br, these polymers crystallize in orthorhombic unit cells with dimensions a = 6.684(1) Å,…
Spin dynamics in mesoscopic size magnetic systems:AHtNMR1study in rings of iron (III) ions
Two magnetic molecular clusters containing almost coplanar rings of iron (III) ions with spin S=5/2 have been investigated by $^{1}\mathrm{H}$ NMR and relaxation measurements. The first system, which will be referred to as Fe6, is a molecule of general formula [${\mathrm{NaFe}}_{6}$(${\mathrm{OCH}}_{3}$${)}_{12}$(${\m…
Self‐assembled second order nonlinear optical multilayer azo polymer
Abstract An epoxy based polymer with nonlinear optical azo chromophores was designed to contain anionic groups to induce water solubility and self assembly. Using this polyanion with a polycation, multilayers were prepared on a glass substrate by alternating adsorption from dilute aqueous solutions. The azo chromophor…