Correlating thermochromic and mechanochromic phosphorescence with polymorphs of a complex gold(i) double salt with infinite aurophilicity

A complex [Au(NHC)(2)][Au(C?N)(2)] double salt exhibits polymorphic crystalline structures with distinct phosphorescence and variations at AuAu distances and ligand-ligand torsion angles. This serves as a model system correlating aurophilicity and low-energy charge-transfer electronic transitions and helps to understand the thermochromism and mechanochromism of the gold(i) complexes.