Gold–Gold Interactions

Abstract

This chapter focuses mainly on closed shell gold(I) atoms which are found to feel attraction among themselves. This attraction is able to modify expected geometries or support one-, two-or three-dimensional arrays and also leads to interesting properties. Closed shell metal cations are expected to repel each other. Nevertheless, an important number of examples containing [d 8 -d 10 -s 2 ] interactions are known. Particularly strong evidence has been accumulated on the attraction between two or more d 10 shells. In the case of gold(I) such attraction between two or more monovalent gold(I) ions in compounds has been observed structurally for a long time. In these situations the gold centers approach each other to a distance of between 2.7 and 3.3 Å. This range includes the distance between gold atoms in gold metal and approaches, or even overlaps with the range of distances found in the few real Au-Au single bonds. Schmidbaur coined the name aurophilic attraction in 1990 and defined it as the unprecedented affinity between gold atoms even with closed-shell electronic configurations and equivalent electrical charges [1]. Since that moment, aurophilicity has become one of the hot topics in gold chemistry, at first with the aim of understanding such interaction, more recently because of the observation that it may play an important role in interesting properties, thus understanding and modulating aurophilic interactions could help to govern these properties, which include the optical behavior. Although different origins are possible for the luminescent emissions of coordination complexes, such as intraligand transitions (ILT), ligand to metal or metal to ligand charge transfer transitions (LMCT, MLCT) and metal centered (MCT) transitions, in many luminescent gold complexes the emissions have been related to the presence of aurophilic interactions.Information about aurophilicity and chemical situations in which it is observed may be found in different works that may be classified as those which analyse closed shell interactions in general [2], those focused on aurophilicity [1,3], and others which analyze the role of these interactions in coordination [4] and organometallic gold Modern Supramolecular Gold Chemistry: Gold-Metal Interactions and Applications. Edited by Antonio Laguna

Highly Efficient Aggregation-Induced Room-Temperature Phosphorescence with Extremely Large Stokes Shift Emitted from Trinuclear Gold(I) Complex Crystals

“…Therefore, the results indicate that those electronic transitions in the excitation spectra can be assigned as a ligand-to-metal-metal charge transfer (LMMCT) transition. The broad photoluminescence band without vibronic structures observed at ~730 is consistent with the previously reported luminescence band for crystal of similar Au complexes [13,14], and it has been proposed that the luminescence is originated from metal-centered excimeric states based on the Au-Au interaction [14]. The computational results also support that the luminescence in the DTn crystals was emitted from the metal-centered excimeric states.…”

“…Molecules containing Au(I) ions are examples of AIEgens that exhibit strong photoluminescence in condensed phases [13][14][15][16][17]. The aurophilic interaction between Au atoms in Au containing complexes is an important property which induces luminescence in their aggregates [13,14].…”

“…Molecules containing Au(I) ions are examples of AIEgens that exhibit strong photoluminescence in condensed phases [13][14][15][16][17]. The aurophilic interaction between Au atoms in Au containing complexes is an important property which induces luminescence in their aggregates [13,14]. As luminescence of the Au-Au interaction is as large as that of the hydrogen bond [13][14][15][16], and for this reason it is often utilized for the formation of supramolecular assemblies [18][19][20][21].…”

“…The aurophilic interaction between Au atoms in Au containing complexes is an important property which induces luminescence in their aggregates [13,14]. As luminescence of the Au-Au interaction is as large as that of the hydrogen bond [13][14][15][16], and for this reason it is often utilized for the formation of supramolecular assemblies [18][19][20][21]. We also anticipated that multiple Au-Au intermolecular interactions would improve the restriction of the internal motion and would further enhance the AIE effects in condensed phases of the complexes.…”

Constrained Digold(I) Diaryls: Syntheses, Crystal Structures, and Photophysics

“…[5][6][7] Organogold(I) complexes often carry bulky phosphine ligands [8,9] that suppress aurophilic contacts. [10][11][12] However, organolithium reagents limit syntheses to nonreducible substrates.…”