Gold: Inorganic & Coordination Chemistry

Abstract

Gold compounds are finding new applications in catalysis, medicine, and molecular materials, based on their reactivity and unusual physical and chemical properties. The theoretical basis of the unique properties of gold compounds continues to develop rapidly and provides a constant challenge for synthesis of new types of gold compounds. This chapter gives an overview of these exciting developments while giving an overview of the modern inorganic chemistry of gold.

On the gold–ligand covalency in linear [AuX2]− complexes

“…9 One of the most common oxidation states of gold is Au(I) with a coordination number of two and usually in a linear geometry. 10 The preference of coordination number two in Au(I) has been shown to be strengthened by relativistic effects. 2c Gold 5d contributions to the Au-X bond have been enhanced through relativistic expansion of the 5d orbitals.…”

Gold-Cage Perovskites: A Three-Dimensional AuIII–X Framework Encasing Isolated MX63– Octahedra (MIII = In, Sb, Bi; X = Cl–, Br–, I–)

“…Furthermore, this connectivity would result in halides that are bound only at axial positions to a Au center. Such interactions are unlikely to be stable: the vast majority of Au III –halide complexes have square-planar geometry in the solid state, whereas the few examples having [4 + 1] or [4 + 2] coordination have their axial halides stabilized by strong bonds to other metals or by hydrogen bonding. These constraints preclude an adequate structural description of the gold-cage structure with stoichiometric Au sites (Figure S7B,C).…”

Induced Chirality in Confined Space on Halogen Gold Complexes

“…A square planar gold dimer, rather than monomer ( D 2 h ) interacting with Br ions has been used to simulate the spectra of the liquid and solid composites. Two Br ions, one for each gold ion, have been considered in the simulation changing the coordination number of the gold ions from 4 to 5.The “chain like” (dimer, trimer, ...) structure has already been discussed in literature and corroborated by DFT calculation, which proved that this tendency is strongly connected to the non-negligible relativistic effect in the AuBr bond. − In the XANES simulation, only the first Au shell was considered, neglecting the DMEB organic contributions which are at longer distances.…”

“…Moreover, the occurrence of the Br-Au (2.4 Å) and Br-X(X=Cl, Br, 3.43Å) as well as the longer distance Br-Au(3.5 Å) (see Figure S4 in SI) in all the composites confirms that the Au-DMEB complexes, are mostly connected together in "chain" form (dimer or more connected units). 68,70 Furthermore, the distance in the liquid samples is definitely longer, confirming a lesser packing of the units formed by gold complexes and consequently a weaker interaction between the gold units and the DMEB micelles. σ 4Br-X 6.47(7) 6.47 (7) 2.47 (7) --…”

“…Occurrence of the Au-Au distance at 4.4 Å, indicates that at least two of AuCl 4-x Br x -units are connected together to form a dimer. 68,69 Moreover, the first shell distance is shorter in the solid than in the liquid composites. Furthermore, the XANES simulations indicates that after evaporation of the solvent, DMEB molecules interact more strongly with the Au complexes which is in good agreement with previously observed results(see Table 1).…”