X-ray Crystal Structure of a Metalled Double-Helix Generated by Infinite and Consecutive C*-Ag^I-C* (C*:N¹-Hexylcytosine) Base Pairs through Argentophilic and Hydrogen Bond Interactions

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• 作者：Prof. Dr. Angel Terró ; n ; Blas Moreno-Vachiano ; Antonio Bauz&aacute ; Prof. Dr. Angel Garcí ; a-Raso ; Prof. Dr. Juan Jesú ; s Fiol ; Prof. Miquel Barceló ; -Oliver ; Prof. Dr. Elies Molins and Prof. Antonio Frontera
• 刊名：Chemistry - A European Journal
• 出版年：2017
• 出版时间：February 10, 2017
• 年：2017
• 卷：23
• 期：9
• 页码：2103-2108
• 全文大小：1652K
• ISSN：1521-3765

文摘

The synthesis of a metalled double-helix containing exclusively silver-mediated C*−C* base pairs is reported herein (C*=N¹hexylcytosine). Remarkably, it is the first crystal structure containing infinite and consecutive C*-Ag^I-C* base pairs that form a double helix. The Ag^I ion occupies the center between two C* residues with N(3)−Ag bond lengths of 2.1 Å and short Ag^I−Ag^I distances (3.1 Å) suggesting an interesting argentophilic attraction as a stabilization source of the helical disposition. The solid-state structure is further stabilized by metal-mediated base-pairs, hydrogen bonding and π-stacking interactions. Moreover, the angle N(3)−Ag-N(3) is almost linear in the [Ag(N¹hexylcytosine)₂]⁺ motif and the bases are not coplanar, thus generating a double-strand helical aggregate in the solid state. The noncovalent and argentophilic interactions have been rationalized based on DFT calculations.