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排序方式: 共有148条查询结果,搜索用时 15 毫秒
91.
92.
Luis Sanhueza Diego Cortés-Arriagada Ramiro Díaz Paulina Dreyse Camilo García Iván A. Gonzalez Bárbara Loeb 《International journal of quantum chemistry》2020,120(24):e26412
Density functional theory calculations of polypyridyl ruthenium complexes with polyaromatic ligands have been performed to understand the metal fragment effect on the modulation of their electronic properties and the influence on the aromatic character. The change of positions of the nitrogen atoms in the ligand structure, as well as the metal moiety, seems to influence the electronic behavior of the π-extended structure and the aromatic character of the complexes at both the ground and excited states. In this framework, structural, electronic, and magnetic-based aromaticity indices were used to understand the aromaticity of the free and coordinated ligands. The aromaticity character of the ligands is highly influenced by the metal fragment, and the aromaticity/antiaromaticity is achieved according to both the electron-withdrawing capability of the ligand and the metal fragment. The electronic distribution observed on the aromatic ligand determines their π-stacking ability; thus, it is proposed that the control of the π-stacking ability is modulated according to the electronic nature of the ruthenium moiety. 相似文献
93.
We show that cold dark matter particles interacting through a Yukawa potential could naturally explain the recently observed cores in dwarf galaxies without affecting the dynamics of objects with a much larger velocity dispersion, such as clusters of galaxies. The velocity dependence of the associated cross section as well as the possible exothermic nature of the interaction alleviates earlier concerns about strongly interacting dark matter. Dark matter evaporation in low-mass objects might explain the observed deficit of satellite galaxies in the Milky Way halo and have important implications for the first galaxies and reionization. 相似文献
94.
A general Fatou Lemma is established for a sequence of Gelfand integrable functions from a vector Loeb space to the dual of a separable Banach space or, with a weaker assumption on the sequence, a Banach lattice. A corollary sharpens previous results in the finite-dimensional setting even for the case of scalar measures. Counterexamples are presented to show that the results obtained here are sharp in various aspects. Applications include systematic generalizations of the distribution of correspondences from the case of scalar Loeb spaces to the case of vector Loeb spaces and a proof of the existence of a pure strategy equilibrium in games with private and public information and with compact metric action spaces. 相似文献
95.
A method has been developed for determining the chloride anion with silver nitrate in presence of the hypochlorite, chlorite and chlorate anions.The chlorate anion does not interfere with the determination. In the presence of chlorite anions the figures for Cl' are too low in acid media.The hypochlorite anion should be reduced to the Cl' anion by PENOT'S solution. 相似文献
96.
Sturdy harmonic functions constitute all but the least tractable of the positive harmonic functions in potential-theoretic settings. They are the uniform limits on compact sets of positive, bounded harmonic functions and are also produced by a simple integral representation on the boundary of a natural compactification of the space on which they are defined. The boundary of that compactification is metrizable, and more regular for the Dirichlet problem, in general, than is the Martin boundary if that boundary is even defined in the setting. 相似文献
97.
A pair of bistable [2]rotaxane, molecular shuttles were prepared that combine 1,2-bis(pyridinium)ethane and benzylanilinium recognition sites; acid-base controlled shuttling of DB24C8 was accompanied by a change in colour and/or fluorescence intensity. 相似文献
98.
Loeb SJ 《Chemical Society reviews》2007,36(2):226-235
This tutorial review documents the discovery and application of the supramolecular template (1,2-bis(pyridinium)ethane) subset (24-crown-8) for preparing interlocked molecules. Focus is on the supramolecular chemistry of the pseudorotaxanes formed with various pyridinium axles and crown ether wheels and how this particular class of mechanically linked molecule has been (i) used to construct rudimentary molecular machines such as molecular shuttles and flip switches, (ii) used as ligands for coordination chemistry and (iii) used to create metal-organic framework (MORF) materials. 相似文献
99.
A necessary condition is given on the Fourier transforms of a finite family of functions in Rsso that the finite family and their translates will approximate an arbitrary function within certain precision. 相似文献
100.