The aurophilicity phenomenon: A decade of experimental findings, theoretical concepts and emerging applications

Abstract

The term 'aurophilicity' was introduced in 1989 to describe phenomena in the structural chemistry of gold which could not be readily rationalized by conventional concepts of chemical bonding. In the following decade the aurophilicity concept has been widely applied and supported by the results of many experimental as well as theoretical studies. It will be carried over into the new millennium as a continued incentive for investigations that will help in the understanding of the unique properties of gold.

Design of luminescent sulfur-containing polynuclear gold(I) complexes for advanced nanomaterials and chemosensors

“…Hydrogen sulfide gas was slowly bubbled into a suspension of the dinuclear gold(I) diphosphine chloride complex, 2 have been determined and the results published previously (7,8). [Au 12 (μ-dppm) 6 (μ 3 -S) 4 ](PF 6 ) 4 shows an interesting 'crossroad-sign' structure with the four Au 3 S units located at the core and interconnected by six dppm ligands, whereas [Au 10 {μ-Ph 2 PN( n Pr)PPh 2 } 4 (μ 3 -S) 4 ](PF 6 ) 2 is propellershaped with four [Au 2 {Ph 2 PN( n Pr)PPh 2 }] flaps connected by four sulfur atoms that are further bonded to two interstitial gold atoms.…”

“…Excitation in the solid state and in solution with visible light at room temperature and at 77 K results in intense dual phosphorescence in the green and orange-red regions. Figure 1 shows the emission spectrum of [Au 10 {Ph 2 PN( n Pr)PPh 2 } 4 S 4 ](PF 6 ) 2 in degassed dichloromethane at 298 K. The low-energy emission in the orange-red region is tentatively assigned to originate from triplet states of a LMMCT (S→Au ... Au) character that mixed with metal-centred (ds/dp) states, while the high-energy emission in the green is attributed to the metal-perturbed phosphine-centred phosphorescence.…”

“…This phenomenon, called aurophilicity by Schmidbaur, is attributed to the strong relativistic effects possessed by gold which lower the energy difference between the 5d and the 6s/p orbitals and give rise to a more effective configuration mixing of the molecular orbitals (2,3). With a closed-shell electronic configuration of d 10 , gold(I) can, as a result, form stronger homonuclear sub-bonding interactions intermolecularly and/or intramolecularly and give birth to a wide diversity of polynuclear aggregates (1, 3 -5).…”

The supramolecular chemistry of gold and l -cysteine: Formation of photoluminescent, orange-emitting assemblies with multilayer structure

“…It is known that cysteine residues reduce Au 3+ to form Au + species [6,7], which is a critical step in the formation of photoluminescent products [8,9]. Recently, the chemistry of gold and biogenic thiols (including Cys) has been investigated at the molecular level.…”

On the selection and design of proteins and peptide derivatives for the production of photoluminescent, red-emitting gold quantum clusters

“…Tyrosine, on the other hand, could be essential, since it could reduce Au III to unstable Au II species [30], which can be an important step in the reaction. Moreover, cysteine has been reported to facilitate the formation of Au I thiolate polymers [31], which are responsible for the attractive forces in clusters through aurophilic interaction [32][33][34][35].…”