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.

Enhanced Metallophilicity in Metal–Carbene Systems: Stronger Character of Aurophilic Interactions in Solution

“…In the past, we discussed the effect of strong electron‐donor ligands on closed‐shell metal ions, and postulated that M–M interactions may surpass the van der Waals radii . In particular, the cationic [Ag 2 (bisNHC) 2 ] 2+ system behaves as a host for Ag + ions and revealed argentophilic interactions in solution.…”

Hirshfeld and DFT analysis of the N-heterocyclic carbene proligand methylenebis(N-butylimidazolium) as the acetonitrile-solvated diiodide salt

“…Good yields were also obtained by refluxing 1-butylimidazole and CH 2 I 2 in acetonitrile, followed by filtration and purification with Et 2 O (Sun et al, 2015). This last procedure has been applied to the isolation of [H 2 BisBuIm]I 2 in our case (Vellé et al, 2014;Cebollada et al, 2015)…”

“…[H 2 BisBuIm]I 2 was synthesized according to the method of Cebollada et al (2015). Colourless crystals of [H 2 BisBuIm]I 2 Á-CH 3 CN, (I), were obtained from a saturated solution of [H 2 BisBuIm]I 2 in acetonitrile (277 K, 10 ml, one week).…”

“…We report here the characterization of the bis(imidazolium) salt methylenebis(N-butylimidazolium) diiodide, [H 2 BisBuIm]I 2 , and its isolation as the crystalline material [H 2 BisBuIm]I 2 Á-CH 3 CN, (I), in combination with a Hirshfeld surface analysis and density functional theory (DFT) calculations. Although the [H 2 BisBuIm] 2+ cation has been frequently utilized, its solid-state structure has not been described previously (see, for example, Poyatos et al, 2003;Quezada et al, 2003Quezada et al, , 2004Jin et al, 2005;Lee et al, 2008;Yang et al, 2008Yang et al, , 2010 Lai et al, 2013;Zou et al, 2014;Aliaga-Lavrijsen et al, 2015;Cebollada et al, 2015;Li et al, 2015;Krü ger et al, 2015;Sun et al, 2015).…”

Dinuclear Gold(I) Complexes Bearing N,N′‐Allyl‐Bridged Bisimidazolylidene Ligands

“…It might be reasonable that the purple gold nanoparticles formed "in traces" facilitate the photo-isomerisation, allowing a change of E-to Z-configuration at lower energies (366 nm). It is known from the literature that nanoparticles as photocatalysts [16] or a third cation via metalmetal interaction [17] can promote (photo)-isomerisation processes.…”