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Anton Lishchynskyi Fedor M. Miloserdov Eddy Martin Jordi Benet‐Buchholz Eduardo C. Escudero‐Adn Andrey I. Konovalov Vladimir V. Grushin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(50):15504-15508
First evidence for the existence of free trifluoromethyl anion CF3− has been obtained. The 3D‐caged potassium cation in [K(crypt‐222)]+ is inaccessible to CF3−, thus rendering it uncoordinated (“naked”). Ionic [K(crypt‐222)]+ CF3− has been characterized by single‐crystal X‐ray diffraction, solution NMR spectroscopy, DFT calculations, and reactivity toward electrophiles. 相似文献
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Polly L. Arnold Alessandro Prescimone Joy H. Farnaby Stephen M. Mansell Simon Parsons Nikolas Kaltsoyannis 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(23):6839-6843
The diuranium(III) compound [UN′′2]2(μ‐η6:η6‐C6H6) (N′′=N(SiMe3)2) has been studied using variable, high‐pressure single‐crystal X‐ray crystallography, and density functional theory . In this compound, the low‐coordinate metal cations are coupled through π‐ and δ‐symmetric arene overlap and show close metal CH contacts with the flexible methyl CH groups of the sterically encumbered amido ligands. The metal–metal separation decreases with increasing pressure, but the most significant structural changes are to the close contacts between ligand CH bonds and the U centers. Although the interatomic distances are suggestive of agostic‐type interactions between the U and ligand peripheral CH groups, QTAIM (quantum theory of atoms‐in‐molecules) computational analysis suggests that there is no such interaction at ambient pressure. However, QTAIM and NBO analyses indicate that the interaction becomes agostic at 3.2 GPa. 相似文献
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