Aurophilicity

In <a href="/facts/Chemistry/SrNqkGVm">chemistry</a>, aurophilicity refers to the tendency of <a href="/facts/Gold/1znknojp">gold</a> <a href="/facts/Complex_(chemistry)/1tCyeQUm">complexes</a> to aggregate via formation of weak <a href="/facts/Metallophilic_interaction/4l9Fuc6r">metallophilic interactions</a>.
The main evidence for aurophilicity is from the <a href="/facts/Crystallography/9B5toeqG">crystallographic</a> analysis of Au(I) complexes. The aurophilic bond has a length of about 3.0 <a href="/facts/Angstrom/T5mjdd97">Å</a> and a strength of about 7–12 <a href="/facts/Kilocalorie/ntNMPx65">kcal</a>/mol, which is comparable to the strength of a <a href="/facts/Hydrogen_bond/85V86IIg">hydrogen bond</a>. The effect is greatest for gold as compared with copper or silver—the higher <a href="/facts/Chemical_element/0jducgWD">elements</a> in its <a href="/facts/Periodic_table_group/YGBcUabv">periodic table group</a>—due to increased <a href="/facts/Relativistic_quantum_chemistry/8A1se1CS">relativistic effects</a>. Observations and theory show that, on average, 28% of the binding energy in the aurophilic interaction can be attributed to relativistic expansion of the gold <a href="/facts/Atomic_orbital/tKhgl6mL">d orbitals</a>.
An example of aurophilicity is the propensity of gold centres to aggregate. While both <a href="/facts/Intramolecular_force/f2Wxm1l3">intramolecular</a> and <a href="/facts/Intermolecular/xIcFMvL7">intermolecular</a> aurophilic interactions have been observed, only intramolecular aggregation has been observed at such nucleation sites.

Aurophilicity open-in-new

Aurophilicity