title: X-ray Crystal Structure of a Metalled Double-Helix Generated by Infinite and Consecutive C*-AgI-C* (C*:N1-Hexylcytosine) Base Pairs through Argentophilic and Hydrogen Bond Interactions.
abstract: 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*-AgI-C* base pairs that form a double helix. The AgIion occupies the center between two C* residues with N(3)-Ag bond lengths of 2.1 Å and short AgI-AgIdistances (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.
authors.affiliation: Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Angel
authors.identifier: http://orcid.org/0000-0002-7599-8288
authors.initials: A
authors.lastname: Terrón
authors.affiliation: Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Blas
authors.initials: B
authors.lastname: Moreno-Vachiano
authors.affiliation: Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Antonio
authors.identifier: http://orcid.org/0000-0002-5793-781X
authors.initials: A
authors.lastname: Bauzá
authors.affiliation: Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: García-Raso
authors.affiliation: Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Juan Jesús
authors.identifier: http://orcid.org/0000-0003-2480-265X
authors.initials: JJ
authors.lastname: Fiol
authors.affiliation: Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Miquel
authors.identifier: http://orcid.org/0000-0003-4309-4118
authors.initials: M
authors.lastname: Barceló-Oliver
authors.affiliation: Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
authors.forename: Elies
authors.identifier: http://orcid.org/0000-0003-1012-0551
authors.initials: E
authors.lastname: Molins
authors.affiliation: Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Antonio
authors.identifier: http://orcid.org/0000-0001-7840-2139
authors.initials: A
authors.lastname: Frontera
keywords: X-ray crystallography; density functional calculations; helical structures; silver; solid-state structures