Trinuclear Gold(I) Triazolates: A New Class of Wide-Band Phosphors and Sensors

A new cyclic gold(I) triazolate trimer, [Au(3,5-i-Pr2Tz)]3 (1), exhibits
fully overlapping aurophilically bonded dimer-of-trimer units that
lead to multiple phosphorescence bands in both the solid state
and solution. The conformation of the hexanuclear unit exhibits
reversible interconversion between C2 and D3 effective symmetries,
depending on the crystal temperature or solution concentration,
the variation of which leads to isoemissive and isosbestic points.
Solutions of 1 exhibit remarkable quenching properties that
demonstrate molecular recognition with high selectivity and
hypersensitivity for some reagents, as influenced by protonation
via Brønsted acids, π intercalation, and/or energy transfer. The
quenched phosphorescence of 1 by acetic acids can be regenerated by NEt3.