排序方式: 共有70条查询结果,搜索用时 15 毫秒
41.
Fluorescent Phosphorus Dendrimer as a Spectral Nanosensor for Macrophage Polarization and Fate Tracking in Spinal Cord Injury
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42.
Dzmitry S. Firaha Dr. Oldamur Hollóczki Prof. Dr. Barbara Kirchner 《Angewandte Chemie (International ed. in English)》2015,54(27):7805-7809
Ionic liquids (ILs), vary strongly in their interaction with CO2. We suggest simple theoretical approach to predict the CO2 absorption behavior of ILs. Strong interaction of the CO2 with the IL anions corresponds to chemical absorption whereas weak interaction indicates physical absorption. A predictive estimate with a clear distinction between physical and chemical absorption can be simply obtained according to geometries optimized in the presence of a solvation model instead of optimizing it only in gas phase as has been done to date. The resulting Gibbs free energies compare very well with experimental values and the energies were correlated with experimental capacities. Promising anions, for ionic liquids with reversible CO2 absorption properties can be defined by a reaction Gibbs free energy of absorption in the range of ?30 to 16 kJ mol?1. 相似文献
43.
Roux MV Notario R Zaitsau DH Emel'yanenko VN Verevkin SP 《The journal of physical chemistry. A》2012,116(18):4639-4645
This paper reports an experimental and computational thermochemical study on 2-thiobarbituric acid (2-thioxodihydropyrimidine-4,6(1H,5H)-dione), [CAS 504-17-6]. The value of the standard (p(0) = 0.1 MPa) molar enthalpy of formation in the gas phase at T = 298.15 K has been determined. The energy of combustion was measured by bomb combustion calorimetry, using a rotatory bomb, and from the result obtained, the standard molar enthalpy of formation in the crystalline state at T = 298.15 K was calculated as -(396.8 ± 0.9) kJ·mol(-1). The enthalpy of sublimation was determined using a transference (transpiration) method in a saturated N(2) stream and a value of the enthalpy of sublimation at T = 298.15 K was derived as (118.3 ± 2.2) kJ·mol(-1). From these results a value of -(278.5 ± 2.4) kJ·mol(-1) for the gas-phase enthalpy of formation at T = 298.15 K was determined. Theoretical calculations at the G3 and G4 levels were performed, and a study of the molecular and electronic structure of the compound has been carried out. Calculated enthalpies of formation are in very good agreement with the experimental value. 相似文献
44.
Sergei Kotelnikov Andrey Alekseenko Cong Liu Mikhail Ignatov Dzmitry Padhorny Emiliano Brini Mark Lukin Evangelos Coutsias Ken A. Dill Dima Kozakov 《Journal of computer-aided molecular design》2020,34(2):179-189
We describe a new template-based method for docking flexible ligands such as macrocycles to proteins. It combines Monte-Carlo energy minimization on the manifold, a fast manifold search method, with BRIKARD for complex flexible ligand searching, and with the MELD accelerator of Replica-Exchange Molecular Dynamics simulations for atomistic degrees of freedom. Here we test the method in the Drug Design Data Resource blind Grand Challenge competition. This method was among the best performers in the competition, giving sub-angstrom prediction quality for the majority of the targets. 相似文献
45.
Verevkin SP Zaitsau DH Emel'yanenko VN Schick C Jayaraman S Maginn EJ 《Chemical communications (Cambridge, England)》2012,48(55):6915-6917
We used DSC for determination of the reaction enthalpy of the synthesis of the ionic liquid [C(4)mim][Cl]. A combination of DSC and quantum chemical calculations presents a new, indirect way to study thermodynamics of ionic liquids. The new procedure was validated with two direct experimental measurements and MD simulations. 相似文献
46.
Zaitsau DH Kabo GJ Strechan AA Paulechka YU Tschersich A Verevkin SP Heintz A 《The journal of physical chemistry. A》2006,110(22):7303-7306
Vapor pressures for a series of 1-n-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (alkyl = ethyl, butyl, hexyl, and octyl) ionic liquids (ILs) were measured by the integral effusion Knudsen method. Thermodynamic parameters of vaporization for ILs were calculated from these data. The absence of decomposition of ILs during the vaporization process was proved by IR spectroscopy. Enthalpies of vaporization of ILs were correlated with molar volumes and surface tensions of the compounds. 相似文献
47.
ZAITSAU Dzmitry H. YERMALAYEU Andrei V. EMEL’YANENKO Vladimir N. VEREVKIN Sergey P. WELZ-BIERMANN Urs SCHUBERT Thomas 《中国科学:化学(英文版)》2012,55(8):1525-1531
The enthalpies of vaporization for the series of pyridinium-based ionic liquids with bis(trifluoromethylsulfonyl)imide anion [CnPy][NTf2] (n = 2, 3, 4, 5, and 6) have been determined with the quartz crystal microbalance technique combined with the Langmuir evaporation. The linear dependence of vaporization enthalpies on the chain length has been revealed. New approach based on volumetric, surface tension, and speed of sound measurements has been developed for estimation of heat capacity differences between gas and liquid phase, which were required for adjustment of measured vaporization enthalpies to the ref- erence temperature 298 K. 相似文献
48.
Dispersion and Hydrogen Bonding Rule: Why the Vaporization Enthalpies of Aprotic Ionic Liquids Are Significantly Larger than those of Protic Ionic liquids
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Dr. Dzmitry H. Zaitsau Dr. Vladimir N. Emel'yanenko Peter Stange Prof. Dr. Christoph Schick Prof. Dr. Sergey P. Verevkin Prof. Dr. Ralf Ludwig 《Angewandte Chemie (International ed. in English)》2016,55(38):11682-11686
It is well known that gas‐phase experiments and computational methods point to the dominance of dispersion forces in the molecular association of hydrocarbons. Estimates or even quantification of these weak forces are complicated due to solvent effects in solution. The dissection of interaction energies and quantification of dispersion interactions is particularly challenging for polar systems such as ionic liquids (ILs) which are characterized by a subtle balance between Coulomb interactions, hydrogen bonding, and dispersion forces. Here, we have used vaporization enthalpies, far‐infrared spectroscopy, and dispersion‐corrected calculations to dissect the interaction energies between cations and anions in aprotic (AILs), and protic (PILs) ionic liquids. It was found that the higher total interaction energy in PILs results from the strong and directional hydrogen bonds between cation and anion, whereas the larger vaporization enthalpies of AILs clearly arise from increasing dispersion forces between ion pairs. 相似文献
49.
Karolin Maljutenko Victor Borovkov Dzmitry Kananovich Ivar Järving Margus Lopp 《Tetrahedron》2018,74(6):661-664
A method for the aerobic cascade oxidation of cyclopentane-1,2-diones using metal porphyrins as catalysts, yielding hydroxydiacids 2, ketoacid 3 and diketoacids 4 which are the intermediates of important biologically active compounds is reported. This method is operationally simple and can be employed under ambient conditions. 相似文献
50.