Aurophilicity
Aurophilicity is the tendency of gold atoms to group together. It makes chemical bonds called aurophilic bonds. Atoms in aurophilic bonds are normally between 2.7 and 3.3 angstroms apart, similar to the distance between atoms in gold metal (2.88 Å).[1] These bonds are stronger than van der Waals interactions but weaker than covalent or ionic bonds.
Aurophilicity is also seen in gold's chemical congeners, copper and silver,[2] and its neighbours, platinum and mercury.[3] Researchers have not found evidence of aurophilicity in palladium.[4] All of these bonds are or are predicted to be much weaker than an aurophilic bond between two gold atoms.
Mechanism
[change | change source]The exact way that aurophilicity works is controversial. A common theory says aurophilicity is caused by interactions between electrons in gold's complete d orbitals. The effect is stronger in gold than with copper or silver because of relativistic effects.[5]
Other chemists disagree with this theory, and predict that the force between the gold atoms alone should push them apart due to Pauli repulsion. The short distance between them is instead because other forces from the ligands are strnoger than this force, making a net attraction between the atoms.[6]
References
[change | change source]- ↑ Schmidbaur, Hubert (2000). "The aurophilicity phenomenon: A decade of experimental findings, theoretical concepts and emerging applications". Gold Bulletin. 33: 3–10. doi:10.1007/BF03215477.
- ↑ Assadollahzadeh, Behnam; Schwerdtfeger, Peter (2008). "A comparison of metallophilic interactions in group 11[X–M–PH3] (N= 2–3) complex halides (M = Cu, Ag, Au; X = Cl, Br, I) from density functional theory". Chemical Physics Letters. 462 (4–6): 222–228. doi:10.1016/j.cplett.2008.07.096.
- ↑ Reboiro, Félix; Blasco, Daniel; Olmos, M. Elena; López-De-Luzuriaga, José M.; Monge, Miguel (2025). "Unraveling Unsupported Gold···Platinum Metallophilic Interactions: An In-Depth Computational and Topological Study". Inorganic Chemistry. 64 (34): 17121–17134. doi:10.1021/acs.inorgchem.5c01042. PMC 12406201. PMID 40561233.
- ↑ Reboiro, Félix; Olmos, M. Elena; López-De-Luzuriaga, José M.; Monge, Miguel (2026). "On the nature and feasibility of unsupported Au⋯Pd metallophilic interactions: A correlated computational study". Dalton Transactions. 55 (11): 4406–4420. doi:10.1039/D6DT00023A. PMID 41705410.
- ↑ Pawlȩdzio, Sylwia; Malinska, Maura; Kleemiss, Florian; Grabowsky, Simon; Woźniak, Krzysztof (2022). "Aurophilic Interactions Studied by Quantum Crystallography". Inorganic Chemistry. 61 (10): 4235–4239. doi:10.1021/acs.inorgchem.1c03333. PMID 35230099.
- ↑ Wan, Qingyun; Yang, Jun; To, Wai-Pong; Che, Chi-Ming (2021). "Strong metal–metal Pauli repulsion leads to repulsive metallophilicity in closed-shell d 8 and d 10 organometallic complexes". Proceedings of the National Academy of Sciences. 118 (1) e2019265118. Bibcode:2021PNAS..11819265W. doi:10.1073/pnas.2019265118. PMC 7817198. PMID 33372160.