Direct X‐Ray Scattering Evidence for Metal–Metal Interactions in Solution at the Molecular Level

Abstract

The study of the aggregation of small molecules in solution induced by metallophilic interactions has been traditionally performed by spectroscopic methods through identification of chemical changes in the system. Herein we demonstrate the use of SAXS (small‐angle X‐ray scattering) to identify structures in solution, taking advantage of the excellent scattering intensity of heavy metals which have undergone association by metallophilic interactions. An analysis of the close relationship between solid‐state and solution arrangements of a dynamic [Ag2(bisNHC)2]2+ (NHC=N‐heterocyclic carbene) system, and how they are complementary to each other, is reported.

From Imidazole toward Imidazolium Salts and N-Heterocyclic Carbene Ligands: Electronic and Geometrical Redistribution

“…7 Their strong electron donor ability modifies the electronic properties of the metals, including metallophilicity. 8,9 This enhancement of electron density is systematically exploited in homogeneous and heterogeneous catalysis 10,11 and in the design of potential antitumor metallodrugs. 12 NHCs also exhibit an interesting main-group reaction chemistry that involves, for example, the stabilization of E−E multiple bonds, activation of E−E bonds, ring expansion reactions, and so forth.…”

“…The N1C21N1′ angle between them is 107.8(2)°, close to the expected tetrahedral angle supported by the bridging carbon atom. In addition, the aromatic tails of the phenoxyethyl substituents display a dihedral angle of 52.29 (9)°with the imidazolium rings. The N3C6C7O8 torsion angle is 68.8(2)°.…”