Aurophilicity versus Mercurophilicity: Impact of d¹⁰–d¹⁰ Metallophilic Interactions on the Structure of Metal‐Rich Supramolecular Assemblies

Abstract

Treatment of U-shaped, binuclear Cu(I) complexes 1,1' (1, counterion: BF(4)(-); 1', counterion: PF(6)(-)) with metal cyanide linear linkers K[Au(CN)(2)] (3) and Hg(CN)(2) (4) lead to formation of new supramolecular assemblies 5,5' and 6,6', respectively, in good yield. These derivatives have been characterized by NMR spectroscopy, IR, and X-ray diffraction studies. Derivative 5,5' are supramolecular metallacycles in which intramolecular aurophilic interactions between the Au(I) metal centers of the linkers are observed. Derivative 5 crystallizes as a single solid phase, whereas derivative 5' is characterized in the solid state as four different pseudo-polymorphs (5'a-d). Notably in the case of phase 5'd, a dimer of supramolecular metallacycles bounded by intermolecular aurophilic interactions is formed. Conversely, derivatives 6,6' present large structural diversity depending on the nature of the counterion. Derivative 6 is a supramolecular rectangle in which the Hg(II)-Hg(II) metal distance suggests mercurophilic interaction, whereas 6' crystallizes as two different pseudo-polymorphs 6'a,b, that is, a one-dimensional coordination polymer and one oligomer with no short Hg(II)-Hg(II) metal contacts, respectively. In derivatives 6,6', short contacts between the Hg(II) metal centers and fluorine atoms of the counterions are also observed, which may explain the counterion structural dependence of these supramolecular assemblies based on Hg(II) metal cyanide linker. Comparison of the different solid-state structures characterized highlights the importance of weak secondary interactions between the linkers for the formation supramolecular metallacycles from molecular clips 1,1' and suggests the range of energies required for these interactions to form metallacycles and to induce self-aggregation.

Role of Hg...Hg Interactions in Structure Stability of [HgX]- (X = Cl, Br, I) Based Inorganic-Organic Hybrid Compounds

“…The Hg…Hg distance in compound HgCl1 is calculated as 3.831(1) Å which shows that the structure is stabilized by metallophilic interactions apart from X-H…A and Cl…Cl secondary interactions 10,12 . Similar pattern of mercurophilic interactions is observed in HgCl2 derivative with Hg…Hg distance of 3.920(2) Å.…”

“…Hg…Hg interactions are designated as mercurophilic interactions and depicts an interesting phenomenon of d 10 …d 10 metal contacts [9][10][11][12] . As part of our research on secondary interactions in organic-inorganic hybrid materials 11 , three series of compounds whose crystal structures have already been reported have been selected based on [HgX] -, (X = Cl, Br, I) anion for study of mercurophilic interactions through crystallography data.…”

Can Coordination‐Driven Supramolecular Self‐Assembly Reactions Be Conducted from Fully Aliphatic Linkers?

“…31 P{ 1 H} NMR spectra recorded in CD2Cl2 [11] indicate that the Cu I 2(B)2 moiety is maintained (Table S1) ). The solid state molecular structures of all the derivatives 10-18 were established by X-ray diffraction studies [8,13] performed on single crystals obtained at RT from pentane diffusion into CH2Cl2 crude solutions.…”

“…[8] Derivative A was previously identified as a versatile and strongly convergent 'U-shape' molecular clip for the CDS syntheses of a large series of compact metallacycles C [9] upon its reaction with various ditopic cyano-capped π-conjugated linkers [10] or with the metal-based linear linker [Au(CN)2] -(Scheme 1a). [11] Within the resulting assemblies, specific inter-linkers interactions (π-π or aurophilic intra-and intermolecular interactions) were observed, playing presumably a key role in the selective formation of these compact metallacycles, which was recently supported by the reaction of A with a series of cyano-capped ditopic linkers carrying both 'rigid' π-conjugated systems and 'flexible' linear [a] Dr Accepted Manuscript Figure 1. Views of the X-ray crystal structures [13] of the tetracationic metallacycles 10, 14b, 15, 16 and 17 (counteranions, H atoms of the ligands B and solvent molecules have been omitted for clarity).…”

“…The solid state molecular structures of all the derivatives 10-18 were established by X-ray diffraction studies [8,13] performed on single crystals obtained at RT from pentane diffusion into CH2Cl2 crude solutions. In all the supramolecular structures 10-18, Cu I 2(B)2 fragments present the coordination modes for the ligands B usually observed in the derivatives A, C and D. [7,[10][11][12] All the P-phenyl substituents point towards the cyano-ligands, which correspond to a preferred configuration of the ligands B in which the sterical constraints in the (Cu I )2(B) fragments are minimized. In addition, all the metric parameters of the dicationic (Cu I )2(B)2 cores of the derivatives 10-18 are very similar to those of the molecular clip A [7] and the metallacycles C-D (Table S4).…”