Phase behavior and structure formation of hairy-rod supramolecules

Phase behavior and microstructure formation of rod and coil molecules, which can associate to form hairy-rod polymeric supramolecules, are addressed theoretically. Association induces considerable compatibility enhancement between the rod and coil molecules and various microscopically ordered structures can appear in the compatibility region. The equilibria between microphase-separated states, the coil-rich isotropic liquid and the rod-rich nematic are discussed in detail. In the regime where hairy-rod supramolecules with a high grafting density appear as a result of the association, three phase diagram types are possible depending on the value of the association energy. In the low grafting density regime only the lamellar microstructure is proven to be stable.Received: 10 June 2003, Published online: 21 November 2003PACS: 36.20.-r Macromolecules and polymer molecules - 64.60.Cn Order-disorder transformations; statistical mechanics of model systems     

Correlated strength in the nuclear spectral function

We have carried out an (e,e'p) experiment at high momentum transfer and in parallel kinematics to measure the strength of the nuclear spectral function S(k,E) at high nucleon momenta k and large removal energies E. This strength is related to the presence of short-range and tensor correlations, and was known hitherto only indirectly and with considerable uncertainty from the lack of strength in the independent-particle region. This experiment locates by direct measurement the correlated strength predicted by theory.     

Proton spin structure in the resonance region

We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV相似文献   

Reactions of bromine-containing organozinc compounds derived from α,α-dibromo ketones with 2-arylmethylideneindan-1,3-diones and 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones

Bromine-containing organozinc compounds generated from 1,1-dibromo-3,3-dimethylbutan-2-one reacted with 2-arylmethylideneindan-1,3-diones and 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones to give 3-aryl-2-(2,2-dimethylpropanoyl)spiro[cyclopropane-1,2′-indan]-1′,3′-diones and 1-aryl-6,6-dimethyl-2-(2,2-dimethylpropanoyl)-5,7-dioxaspiro[2.5]octan-4,8-diones, respectively. Reactions of 2-arylmethylideneindan-1,3-diones with bromine-containing zinc enolates derived from 1-aryl-2,2-dibromopropan-1-ones and 2,2-dibromo-1,2,3,4-tetrahydronaphthalen-1-one resulted in the formation of 2-aroyl-3-aryl-2-methylspiro-[cyclopropane-1,2′-indan]-1′,3′-diones and 2,3: 8,9-dibenzo-12-phenyldispiro[4.0.5.1]dodecane-1,4,7-trione, respectively.     

Synthesis and Antibacterial Activity of New Oxadiazolylbenzodioxane Derivatives

Russian Journal of Organic Chemistry - Reactions of 5-(1,4-benzodioxan-2-yl)-1,3,4-oxadiazole-2-thiol with N-substituted chloroacetamides gave a series of the corresponding derivatives at the...     

X-ray diffraction study of organic and inorganic polymeric binders

For improving water-resistivity, adhesion, and physical-mechanical properties of silicate coatings, we have developed a technique of modification of silicate film-forming materials with organic polymer-forming monomers (e.g., aldehydes and amines), oligomers, and other additives. The inner structure of the modified silicate converter was studied by X-ray diffraction method. It is shown that addition of polymer-forming monomers leads to increase in the fraction of crystalline phase with respect to amorphous. The described modification technique seems to be more perspective, since it allows producing coatings with good anticorrosive, physical-mechanical, and other valuable properties.     

Power series with radius of convergence zero — Overconvergence,elongations, summability

We deal with overconvergence phenomena of power series with radius of convergence zero. Among others it is shown that the partial sums of such a series can be elongated to become Cesàro summable on a set S ⊂ {z: |z| > 0} if and only if the considered power series is overconvergent.     

Synthesis of novel chiral NiII complexes of dehydroalanine Schiff bases and their reactivity in asymmetric nucleophilic addition reactions. Novel synthesis of (S)-2-carboxypiperazine

New chiral Ni^II complexes of Schiff bases of dehydroalanine with modified chiral auxiliaries (S)-2-N-[N′-(3,4-dichlorobenzyl)prolyl]aminobenzophenone (3,4-DCBPB), (S)-2-N-[N′-(3,4-dimethylbenzyl)prolyl]aminobenzophenone (3,4-DMBPB), (S)-2-N-[N′-(2-chlorobenzyl)prolyl]aminobenzophenone (2-CBPB), and (S)-2-N-[N′-(2-fluorobenzyl)prolyl]-aminobenzophenone (2-FBPB) have been synthesized. Asymmetric Michael addition reactions of primary and secondary amines and thiols to the dehydroalanine moieties of the complexes were studied. (S)-2-FBPB was found to be the best chiral auxiliary in terms of both selectivity of the reactions (de ～92–96%) and reactivity of the complexes. A novel synthetic route toward (S)-2-carboxypiperazine was developed based on the auxiliary.     

Three-component spiro-heterocyclization of 4,5-diphenyl-1H-pyrrole-2,3-dione under the action of malononitrile and 3-hydroxycyclohex-2-en-1-ones

Russian Journal of Organic Chemistry -