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X‐ray Crystal Structure of a Metalled Double‐Helix Generated by Infinite and Consecutive C*‐Ag I ‐C* (C*:N 1 ‐Hexylcytosine) Base Pairs through Argentophilic and Hydrogen Bond Interactions
Author(s) -
Terrón Angel,
MorenoVachiano Blas,
Bauzá Antonio,
GarcíaRaso Angel,
Fiol Juan Jesús,
BarcelóOliver Miquel,
Molins Elies,
Frontera Antonio
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201604331
Subject(s) - crystal structure , crystallography , helix (gastropod) , x ray crystallography , chemistry , hydrogen , base (topology) , physics , diffraction , optics , ecology , organic chemistry , snail , biology , mathematical analysis , mathematics
The synthesis of a metalled double‐helix containing exclusively silver‐mediated C*−C* base pairs is reported herein (C*=N 1 hexylcytosine). 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(N 1 hexylcytosine) 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.