A heart of gold: The first hexanuclear gold cluster formed exclusively by gold(I) centers (see picture; Au yellow, C black, P purple) has been shown to be catalytically active for the activation of alkynes under homogeneous conditions.

The synthesis of tetranuclear gold complexes, a structurally unprecedented octanuclear complex with a planar [Au^I₈] core, and pentanuclear [Au^I₄M^I] (M=Cu, Ag) complexes is presented. The linear [Au^I₄] complex undergoes C−H functionalization of carbonyl compounds under mild reaction conditions. In addition, [Au^I₄Ag^I] catalyzes the carbonylation of primary amines to form ureas under homogeneous conditions with efficiencies higher than those achieved by gold nanoparticles.

A series of luminescent dinuclear neutral complexes of stoichiometry [(AuSPh)₂(PPh₂-(C₆H₄)_n-PPh₂)] (n = 1, 2, 3) as well as their tetranuclear cationic derivatives [(Au₂SPh)₂(PPh₂-(C₆H₄)_n-PPh₂)₂](PF₆)₂ are reported. Their crystal structures have been elucidated by X-ray studies. These studies indicate that, for the dinuclear species, only when n = 1 the molecules exhibit intermolecular aurophilic interactions. None of the tetranuclear species crystallizes in their molecular form, due to the formation of aggregates through Au⋯Au interactions. The origin of the luminescence has been analyzed by computational studies indicating that the presence or absence of aurophilic interactions does not affect the luminescent behavior and that intraligand charge transfer processes which involve the thiolate and the diphosphine are responsible for the emissions. The result is in contrast with the thiolate–gold charge transfer processes which dominate the photophysics of gold-thiolate compounds and reveals the influence of the phenylene spacers in the emissive behavior of these compounds.

Chloromethylgold(I) complexes of phosphine, phosphite, and N‐heterocyclic carbene ligands are easily synthesized by reaction of trimethylsilyldiazomethane with the corresponding gold chloride precursors. Activation of these gold(I) carbenoids with a variety of chloride scavengers promotes reactivity typical of metallocarbenes in solution, namely homocoupling to ethylene, olefin cyclopropanation, and Buchner ring expansion of benzene.

Reaction of the diphosphanes P∼P [PPh₂(C₆H₄)_nPPh₂ (n = 1–5) and PPh₂CC(C₆H₄)CCPPh₂] with [AuX(tht)] (X = Cl, C₆F₅) in a 1 : 2 molar ratio affords dinuclear luminescent complexes of formula [(AuX)₂(P∼P)]. The photoemissive properties of these complexes are mainly controlled by the presence of the diphosphane ligand, specifically by the phenylene spacers of the diphosphanes. At room temperature fluorescent (IL) processes dominate the emissions, both in solution and in the solid state. Frozen solutions or solids at 77 K display dual emissions or only one emission attributed to ligand to ligand charge transfer (LL′CT) transitions from the auxiliary ligand (L) to phenylene spacers of the diphosphane (L′).