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Maria Brandl Klaus Lindauer Michael Meyer Jürgen Sühnel 《Theoretical chemistry accounts》1999,101(1-3):103-113
Small molecule studies indicate that C–H...X interactions (X: O,N) constitute weak H-bonds. We have performed a comprehensive
analysis of their occurrence and geometry in RNA structures. Here, we report on statistical properties of the total set of
interactions identified and discuss selected motifs. The distance/angle distribution of all interactions exhibits an excluded
region where the allowed C–H...X angle range increases with an increasing H...X distance. The preferred short C–H...X interactions
in RNA are backbone-backbone contacts between neighbour nucleotides. Distance/angle distributions generated for various interaction
types can be used for error recognition and modelling. The axial C2′(H)...O4′ and C5′(H)...O2′ interactions connect two backbone
segments and form a seven-membered ring that is specific for RNA. An AA base pair with one standard H-bond and one C–H...N
interaction has been identified in various structures. Despite the occurrence of short C–H...X contacts their free energy
contribution to RNA stability remains to be assessed.
Received: 17 May 1998 / Accepted: 4 August 1998 / Published online: 2 November 1998 相似文献
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Systematization of the available literature data on C-F...π, F...H, and F...F interactions, namely, statistical studies of
the geometry of the corresponding contacts were carried out using the Cambridge Structural Database (CSD) and theoretical
quantum-chemical estimations of their energies. The most typical supramolecular motifs (finite or infinite) involving the
F atom were revealed based on recent X-ray studies of a few dozens of fluoroarenes carried out at the Novosibirsk Institute
of Organic Chemistry. Our recent data were summarized. To assess the role of the above interactions, we used topological analysis
of electron density distribution in terms of Bader’s QTAIM theory. Our DFT/PBE/3z quantum-chemical calculations of the interaction
energies of molecular pairs in diazafluorene crystals formed by C-F...π, C-F...H, and F...F nonvalent short contacts are presented. 相似文献
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