Halogen Bonding Involving Gold Nucleophiles in Different Oxidation States

Abstract

A single-crystal X-ray diffraction (XRD) study of diaryliodonium tetrachloroaurates (or, in the recent terminology, tetrachloridoaurates), [(p-XC 6 H 4 ) 2 I][AuCl 4 ] (X = Cl, 1; Br, 2), was performed for 1 (the structure is denoted as 1a to show similarity with the isomorphic structure 2a) and two polymorphs�2a (obtained from MeOH) and 2b (from 1,2-C 2 H 4 Cl 2 ). Examination of the XRD data for these three structures revealed 2-center C− X•••Au III (X = Cl and Br) and 3-center bifurcated C−Br•••(Cl−Au) halogen bonding (abbreviated as XB) between the p-Cl or p-Br atoms of the diaryliodonium cations and the gold(III) atom of [AuCl 4 ] − . The noncovalent nature of Au III -involving interactions, the nucleophilicity of the gold(III) atoms, and the electrophilic role of p-X atoms of the diaryliodonium cations in the XBs were studied by a set of complementary computational methods. Combined experimental and theoretical studies allowed the recognition of the dnucleophilicity of the [d 8 Au III ] atom which, regardless of its rather substantial formal 3+ charge, can function as a d-nucleophilic partner of XB. This conclusion was also supported by theoretical calculations performed for the structures' refcodes BINXOM and ICSD 62511; the obtained data verified the nucleophilicity of Au III toward a K + ions or a σ-(Cl)-hole, respectively. All our results, together with consideration of relevant literature, indicate that gold atoms in the three oxidation states (0, I, and even III) exhibit nucleophilicity in XBs.

Exploring Au(i) involving halogen bonding with N-heterocyclic carbene Au(i) aryl complexes in crystalline media

“…S22 †). Note that patterns with multiple XB interactions involving transition metal atoms were previously observed for XB interactions involving Au(III), 39 Pt(II), Pd(II), Ni(II), and Rh(I) complexes. 34…”

Co-crystals of NHC Au(I) Aryl Complexes with Iodoperfluoroarenes as a Platform for the Study of Au(I) Involving Halogen Bonding

“…Meanwhile, in only two cases, one Au(I) metal center was found to participate in two and four XB interactions simultaneously, resulting in 2D supramolecular architectures (Figure S22). Note that patterns with multiple XBs involving transition metal atoms were previously observed for XB interactions involving Au(III), [20] Pt(II), Pd(II), Ni(II), and Rh(I) complexes. [15]…”

Noncovalent Chelation by Halogen Bonding in the Design of Metal-Containing Arrays: Assembly of Double σ-Hole Donating Halolium with CuI-Containing O,O-Donors

“…All our spectral, PXRD, and XRD data were consistent with each other and confirmed the proposed structures. Previously, this approach was successfully used in several works. , Notably, the position and number of resonances in the 1 H, 19 F­{ 1 H}, and 13 C­{ 1 H} NMR spectra and also the multiplicity and integration ratio in the 1 H NMR, in general, confirm the structures of the obtained diamagnetic copper­(I) species. However, some expectable resonances were not found: (i) in the 13 C­{ 1 H} NMR spectra of all complexes, we did not observe corresponding peaks from the oxadiazole C3 and C5 atoms even at a high acquisition and (ii) for complex 3b , two signals of oxadiazole carbons, as well as resonances of two aromatic carbons and five aromatic proton bromolium moieties, were not found, again at a high acquisition.…”