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81.
Eric Sidler Dr. Patrick Zwick Charlotte Kress Ksenia Reznikova Dr. Olaf Fuhr Prof. Dr. Dieter Fenske Prof. Dr. Marcel Mayor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(53):e202201764
The synthetic access to macrocyclic molecular topologies with interesting photophysical properties has greatly improved thanks to the successful implementation of organic and inorganic corner units. Based on recent reports, we realized that pseudo-meta [2.2]paracyclophanes (PCPs) might serve as optimal corner units for constructing 3D functional materials, owing to their efficient electronic communication, angled substituents and planar chirality. Herein, we report the synthesis, characterization and optical properties of four novel all-carbon enantiopure macrocycles bearing three to six pseudo-meta PCPs linked by 1,3-butadiyne units. The macrocycles were obtained by a single step from enantiopure, literature-known dialkyne pseudo-meta PCP and were unambiguously identified and characterized by state of the art spectroscopic methods and in part even by x-ray crystallography. By comparing the optical properties to relevant reference compounds, it is shown that the pseudo-meta PCP subunit effectively elongates the conjugated system throughout the macrocyclic backbone, such that already the smallest macrocycle consisting of only three subunits reaches a polymer-like conjugation length. Additionally, it is shown that the chiral pseudo-meta PCPs induce a remarkable chiroptical response in the respective macrocycles, reaching unprecedented high molar circular dichroism values for all-carbon macrocycles of up to 1307 L mol−1 cm−1. 相似文献
82.
Ksenia I. Kaskevich Maria A. Simonova Margarita M. Romasheva Matvey D. Zelentsov Andrey V. Ziminov Stanislav M. Ramsh Larisa S. Litvinova Sergei A. Cherevkov Alexander P. Filippov Alexander V. Yakimansky 《Journal of polymer science. Part A, Polymer chemistry》2024,62(9):1975-1987
A series of molecular brushes with a polyfluorene (PF) backbone and polymethacrylic acid side chains of varying lengths were prepared by atom transfer radical polymerization. The structure and composition of the synthesized compounds were confirmed by 1H NMR and IR spectroscopy. Effect of the length of the backbone on spectral and conformational parameters of the macromolecules in solutions was analyzed. The grafting density of side chains was about 90%. Spectral methods have been used to determine the dependence of side chain grafting on the luminescent properties of polymer solutions, including quantum yields. It was shown that an optimal length of polymethacrylic acid side chains provides solubility of the polymer brushes. Solutions of PF-graft-polymethacrylic acid complexes with the model substance curcumin were investigated. It was established that the molecular brushes containing curcumin form monomolecular micelles. Molecular brushes with zinc phthalocyanine, potential systems for photodynamic, and photothermal therapy, were studied. 相似文献
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S.S. Khasanov B.Z. Narymbetov L.V. Zorina L.P. Rozenberg R.P. Shibaeva N.D. Kushch E.B. Yagubskii R. Rousseau E. Canadell 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,1(4):419-428
The effect of the first-order phase transition occurring around 220 K on the crystal and electronic structure of the molecular
superconductor (BEDO-TTF) has been studied. The crystal structure at 170 K has been determined and it is found that the main structural change resulting
from the phase transition is connected with a rotation of the anions. This rotation leads to changes in the SS and SO intermolecular contacts within the BEDO-TTF donor layers. How these structural changes affect the electronic structure of
the salt is studied by comparing the transfer integrals for the different donordonor intermolecular interactions calculated for the room temperature and 170 K crystal structures. It is shown that Fermi
surfaces for the 170 K and room temperature structures are very similar, do not exhibit nesting properties, and can be described
as resulting from the hybridization of superposing ellipses.
Received: 4 September 1997 / Received in final form: 2 December 1997 / Accepted: 3 December 1997 相似文献
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88.
S. V. Borodaev M. E. Kletskii N. V. Shibaeva 《Chemistry of Heterocyclic Compounds》1994,30(5):612-615
It has been shown that recyclization of 4-acylmethyl-3-azapyrylium salts under the influence of primary amines affords 4-(-hydrozystyryl)pyrimidinium salts, which, upon further heating with the amine, are recyclized to form 4-acylaminopyridinium salts. It has been established that nucleophilic attack of 6-acylmethyl-substituted 3-azapyrylium salts in aqueous NaOH solution leads to functionally substituted pyridines. By means of MNDO quantum-chemical calculations with an accounting for solvation effects, in a continuum model, it has been shown that two directions of nucleophilic attack of the azapyrylium ring — at positions 2 and 6 — are equally probable.Rostov State University. Scientific-Research Institute of Physical and Organic Chemistry, Rostov State University, Rostov-on-Don 344010. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 697–700, May, 1994. Original article submitted April 18, 1994. 相似文献
89.
N. V. Shibaeva I. I. Nechayuk S. V. Borodaev D. S. Yufit Yu. T. Struchkov A. I. Pyshchev S. M. Luk'yanov 《Chemistry of Heterocyclic Compounds》1991,27(11):1256-1261
Under the influence of DMF/Ac2O 2,4-diphenyl-6-methyl-3-azapyrylium perchlorates undergo condensation to give pyrido[1,2-c]pyrimidinium perchlorates. The structure of one of the perchlorates was proved by x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1556–1561, November, 1991. 相似文献
90.
Let G be a group, and let X be a G-space with the action G × X → X, (g, x) ?gx. A subset A of X is called a kaleidoscopical configuration if there is a coloring χ : X → κ (i.e., a mapping of X onto a cardinal κ) such that the restriction χ|gA is a bijection for each g ∈ G. We survey some recent results on kaleidoscopical configurations in metric spaces considered as G-spaces with respect to the groups of their isometries and in groups considered as left regular G-spaces. 相似文献