RESUMEN
This manuscript reports the synthesis, X-ray characterization and DFT study of three new [M(bipy)3]2[Au(CN)2]3(X) (M = Fe, Co, and Ni; bipy = 2,2'-bipyridine; X = anion) ionic compounds. These salts are composed of [M(bipy)3]2+ dications and [Au(CN)2]- anions in a 2 : 3 ratio. The positive charge is compensated by X = Cl- anions in compounds 1 (M = Fe) and 2 (M = Co) and X = OH- in 3 (M = Ni). The three tridentate bipyridine ligands define the coordination of the M2+ cation, resulting in a nearly octahedral coordination sphere. The linear dicyanoaurate(I) anions are completely surrounded by a cradle of aromatic rings with Au-ring centroid distances below the sum of van der Waals radii, evidencing the existence of a specific Auâ¯π attraction. This interaction has been analyzed in terms of the role of the Au-atom (Lewis acid or Lewis base) using DFT calculations combined with the quantum theory of atoms in molecules (QTAIM), noncovalent interaction plot index (NCIplot) and natural bond orbital (NBO) computational tools. The NBO suggests that the Auâ¯π interaction is an example of a coinage bond in spite of the anionic nature of the acceptor and the cationic nature of the donor.
RESUMEN
The title compound, C15H15Br2NO2, crystallizes with two mol-ecules in the asymmetric unit of the unit cell. In both mol-ecules, the tetra-hydro-furan rings adopt an envelope conformation with the O atom as the flap and the pyrrolidine rings adopt an envelope conformation. In the crystal, mol-ecules are linked by weak C-Hâ¯O hydrogen bonds, forming sheets lying parallel to the (002) plane. These sheets are connected only by weak van der Waals inter-actions. The most important contributions to the surface contacts are from Hâ¯H (44.6%), Brâ¯H/Hâ¯Br (24.1%), Oâ¯H/Hâ¯O (13.5%) and Câ¯H/Hâ¯C (11.2%) inter-actions, as concluded from a Hirshfeld surface analysis.