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991.
Stoikov II Yantemirova AA Nosov RV Rizvanov IKh Julmetov AR Klochkov VV Antipin IS Konovalov AI Zharov I 《Organic & biomolecular chemistry》2011,9(9):3225-3234
New p-tert-butyl thiacalix[4]arenes differently substituted at the lower rim with amide, hydroxyl and ester groups were synthesized. Binding properties of the compounds toward some tetrabutylammonium salts n-Bu(4)NX (X = F(-), Cl(-), Br(-), I(-), CH(3)CO(2)(-), H(2)PO(4)(-), NO(3)(-)) were studied by UV spectroscopy. It was found that the stoichiometry of the complexes, generally, is 1 : 1, and the association constants are in the range of 10(3)-10(5) M(-1). The p-tert-butyl thiacalix[4]arenes containing secondary amide groups trisubstituted at the lower rim bind the studied anions most effectively. Selective receptors for fluoride and dihydrogen phosphate salts of tetrabutylammonium were found. 相似文献
992.
Gerus II Mironetz RX Kondratov IS Bezdudny AV Dmytriv YV Shishkin OV Starova VS Zaporozhets OA Tolmachev AA Mykhailiuk PK 《The Journal of organic chemistry》2012,77(1):47-56
Straightforward practical synthetic approaches to 3,4-bis- and 3,4,5-tris(trifluoromethyl)pyrazoles have been developed. The key step of the both syntheses is a transformation of the carboxylic group in a pyrazole core into the trifluoromethyl group by sulfur tetrafluoride. The elaborated synthetic protocols allow gram-scale preparation of the target products. The obtained compounds are comprehensively characterized by means of crystallographic analysis, determination of pK(a) values and fluorescence measurements. 相似文献
993.
Ekaterina P. Altova Anatolii N. Rykov Natalja Vogt Igor F. Shishkov 《Mendeleev Communications》2021,31(1):81-83
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994.
Igor Lomovskiy Aleksey Bychkov Oleg Lomovsky Tatiana Skripkina 《Molecules (Basel, Switzerland)》2020,25(22)
In recent years, we have witnessed an increasing interest in the application of mechanochemical methods for processing materials in biomass refining techniques. Grinding and mechanical pretreatment are very popular methods utilized to enhance the reactivity of polymers and plant raw materials; however, the choice of devices and their modes of action is often performed through trial and error. An inadequate choice of equipment often results in inefficient grinding, low reactivity of the product, excess energy expenditure, and significant wear of the equipment. In the present review, modern equipment employing various types of mechanical impacts, which show the highest promise for mechanochemical pretreatment of plant raw materials, is examined and compared—disc mills, attritors and bead mills, ball mills, planetary mills, vibration and vibrocentrifugal mills, roller and centrifugal roller mills, extruders, hammer mills, knife mills, pin mills, disintegrators, and jet mills. The properly chosen type of mechanochemical activation (and equipment) allows an energetically and economically sound enhancement of the reactivity of solid-phase polymers by increasing the effective surface area accessible to reagents, reducing the amount of crystalline regions and the diffusion coefficient, disordering the supramolecular structure of the material, and mechanochemically reacting with the target substances. 相似文献
995.
Taniya Olga S. Kopchuk Dmitry S. Khasanov Albert F. Kovalev Igor S. Zyryanov Grigory V. Charushin Valery N. Chupakhin Oleg N. 《Chemistry of Heterocyclic Compounds》2019,55(6):505-507
Chemistry of Heterocyclic Compounds - Microreview focuses on the main modern synthetic approaches toward 2-azaanthracene and its derivatives. These approaches are: inverse electron-demand... 相似文献
996.
997.
Chen Xiaolong He Yaowu Ali Muhammad Umair He Yu Zhu Yanan Li Aiyuan Zhao Changbin Perepichka Igor F. Meng Hong 《中国科学:化学(英文版)》2019,62(10):1360-1364
Herein, we propose a new strategy to develop air-stable n-type organic semiconductors with non-classical thiophene aromatic diimide derivatives by replacing aromatic naphthalene with a heteroaromatic isothianaphthene core. We designed and successfully synthesized the isothianaphthene core based diimide material, N,N′-bis(n-hexyl)isothianaphthene-2,3,6,7-tetracarboxylic acid diimide(BTDI-C6) as an n-type semiconductor. Compared to N,N′-bis(n-hexyl)naphthalene-1,4,5,8-tetracarboxylic acid diimide(NDI-C6), BTDI-C6 possesses a deeper LUMO energy level of-4.21 eV, which is 0.32 eV lower than that of NDI-C6. Both molecular modelling and experimental results elucidated that organic thin film transistors(OTFTs)based on both of these materials exhibit comparable mobilities; however, the threshold voltage of BTDI-C6 based device(+7.5 V) is significantly lower than that of NDI-C6 based counterpart(+34V). Moreover, the low-lying LUMO energy level of BTDI-C6 ensures excellent air-stability which is further validated by the device performance. In addition, BTDI-C6 shows high luminescence while NDI-C6 is not luminescent at all in solution, which reveals the potential application of our newly synthesized material in n-type light-emitting transistors. 相似文献
998.
Zadesenets Andrey V. Garkul Ilia A. Filatov Evgeny Yu. Plyusnin Pavel E. Filippov Tikhon N. Asanova Tatyana I. Korolkov Ilya V. Baidina Iraida A. Asanov Igor P. Korenev Sergey V. 《Journal of Thermal Analysis and Calorimetry》2019,135(1):111-121
Journal of Thermal Analysis and Calorimetry - The explanation of abnormal enhancement of transported energy in colloidal nanoparticles in a liquid has sparked much interest in recent years. The... 相似文献
999.
Dr. Jinhua Sun Artem Iakunkov Dr. Igor A. Baburin Boby Joseph Prof. Vincenzo Palermo Dr. Alexandr V. Talyzin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(3):1103-1108
COF-1 has a structure with rigid 2D layers composed of benzene and B3O3 rings and weak van der Waals bonding between the layers. The as-synthesized COF-1 structure contains pores occupied by solvent molecules. A high surface area empty-pore structure is obtained after vacuum annealing. High-pressure XRD and Raman experiments with mesitylene-filled (COF-1-M) and empty-pore COF-1 demonstrate partial amorphization and collapse of the framework structure above 12–15 GPa. The ambient pressure structure of COF-1-M can be reversibly recovered after compression up to 10–15 GPa. Remarkable stability of highly porous COF-1 structure at pressures at least up to 10 GPa is found even for the empty-pore structure. The bulk modulus of the COF-1 structure (11.2(5) GPa) and linear incompressibilities (k[100]=111(5) GPa, k[001]=15.0(5) GPa) were evaluated from the analysis of XRD data and cross-checked against first-principles calculations. 相似文献
1000.
Sofia Curland Leah Javitt Isabelle Weissbuch David Ehre Meir Lahav Igor Lubomirsky 《Angewandte Chemie (International ed. in English)》2020,59(36):15570-15574
By performing icing experiments on hydrophilic and hydrophobic surfaces of pyroelectric amino acids and on the x‐cut faces of LiTaO3, we discovered that the effect of electrofreezing of super cooled water is triggered by ions of carbonic acid. During the cooling of the hydrophilic pyroelectric crystals, a continuous water layer is created between the charged hemihedral faces, as confirmed by impedance measurements. As a result, a current of carbonic acid ions, produced by dissolved environmental CO2, flows through the wetted layer towards the hemihedral faces and elevates the icing temperature. This proposed mechanism is based on the following: (i) on hydrophilic surfaces, water with dissolved CO2 (pH 4) freezes at higher temperatures than pure water of pH 7. (ii) In the absence of the ionic current, achieved by linking the two hemihedral faces of hydrophilic crystals by a conductive paint, water of the two pH levels freeze at the same temperature. (iii) On hydrophobic crystals with similar pyroelectric coefficients, where there is no continuous wetted layer, no electrofreezing effect is observed. 相似文献