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

A complex [Au(NHC)2][Au(CN)2] double salt exhibits polymorphic crystalline structures with distinct phosphorescence and variations at Au⋯Au 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.