Radical polymerization of radical-labeled monomers: The triarylmethyl-based radical monomer as an example

Recent development of spin-labeled nitroxide-mediated polymerization (NMP) involving successful polymer preparation with high livingness and narrow dispersity in the presence of persistent trityl-based stable radicals attached to the initiators (90% recovery of a trityl radical signal after the polymerization) led us to the preparation of stable organic radical polymers based on trityl radical-substituted monomers using NMP as the method of polymerization despite the claims in the literature about its expected failure. Here, we present successful radical polymerization and NMP of a trityl radical-based tri- and mono-monomer yielding more than 90% recovery of the trityl radical signal. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2656–2664     

Polyvariant modification of di- and tetrahydroxydinaphthylmethanes

Modification of di- and tetrahydroxydinaphthylmethanes yielded a new family of aromatic systems differing by the nature, the number, and positions of functional groups and by the mode of fusion of the naphthalene nuclei. The effect of the starting dinaphthylmethane structure on the modification route was demonstrated.     

Exploiting morph-DAST mediated ring-expansion of substituted cyclic β-amino alcohols for the preparation of cyclic fluorinated amino acids. Synthesis of 5-fluoromethylproline and 5-fluoropipecolic acid

The synthesis of proline analogues bearing a fluorine-containing substituent at the fifth position of the pyrrolidine ring, racemic trans- and cis-5-fluoromethyl prolines, was performed. The key step of the synthesis is a transformation of the CH₂OH-group into the CH₂F-one using morpholinosulfur trifluoride. During the synthesis, an efficient procedure to prepare trans- and cis-5-fluoropipecolic acids was elaborated.     

[3+2] Cyclodimerization of 2-arylcyclopropane-1,1-diesters. Lewis acid induced reversion of cyclopropane umpolung

A novel Lewis acid catalyzed [3+2] cyclodimerization of 2-arylcyclopropane-1,1-dicarboxylates is reported. It is the first example of a reaction wherein a donor-acceptor cyclopropane provides two carbons in a newly formed ring. The described cyclodimerization represents a general convenient approach to polyfunctionalized cyclopentanes.     

Ni基催化剂上未掺杂和氮掺杂的碳纳米纤维生长机理的比较

研究了Ni催化剂上碳纳米纤维,以及Ni和Ni-Cu催化剂上N掺杂的碳纳米纤维的生长机理.结果表明,这两个过程的机理均包含了表面非计量碳化镍的形成,然后是碳或碳和氮通过催化剂颗粒体相的溶解和扩散.     

Nanostructured materials obtained under conditions of hierarchical self-assembly and modified by derivative forms of fullerenes

Gas-sensitive nanocomposites, based on silicon dioxide–metal oxide systems, were obtained via self-assembly using the sol–gel method. Surface morphology diagnostics of nanomaterials, synthesized from sol solutions in a precursor medium based on tetraethoxysilane, were made using atomic force microscopy. The main evolution stages of nanocomposites based on two-component systems were determined. Specific surface area measurements of nanocomposites were made using a Sorbi analytical instrument by the thermal desorption method. A method for increasing the specific surface area and gas-sensitivity of nanomaterials by modifying them using fullerenols is suggested.     

Advanced piezoelectric crystal Ca3TaGa3Si2O14: growth,crystal structure perfection,and acoustic properties

A five-component crystal of the lanthanum–gallium silicate family Ca₃TaGa₃Si₂O₁₄ (CTGS) was grown by the Czochralski method. The CTGS crystal, like the langasite crystal (La₃Ga₅SiO₁₄, LGS), possesses unique temperature properties and the fewer number of the Ga atoms in the unit cell makes the density much lower and, consequently, increases the velocity of acoustic wave propagation. The unit-cell parameters were determined by the powder diffraction technique. The defects in the CTGS crystal structure were studied by X-ray topography, which enables the visualization of growth banding characteristics of crystals grown by the Czochralski method. Surface acoustic wave (SAW) propagation in the CTGS crystal was investigated by the high-resolution X-ray diffraction method on the BESSY II synchrotron radiation source. The velocities of propagation and power flow angles of SAWs in the Y- and X-cuts of the CTGS crystal were determined from the X-ray diffraction spectra.     

DNA sequencing through graphene nanogap: a model of sequential electron transport

Transverse electron transport through DNA nucleobases in graphene nanogap with armchair edges is investigated within the sequential tunneling model using the tight-binding approximation and the master equation technique. The effects of both random positions of nucleotides when DNA repeatedly pulls through graphene nanogap during the decoding process and the Coulomb blockade are studied. We have shown that combined measurements of the tunnel current and its root-mean-square deviation in the regime of sequential electron transport allow to facilitate identification of nucleotides while the effects of Coulomb blockade disturb DNA sequencing.     

On the dynamical coherence of structurally stable 3-diffeomorphisms

We prove that each structurally stable diffeomorphism f on a closed 3-manifold M ³ with a two-dimensional surface nonwandering set is topologically conjugated to some model dynamically coherent diffeomorphism.