Luminescent Au(I)-Thiolate Complexes through Aggregation-Induced Emission: The Effect of pH during and Post Synthesis

Luminescent Au(I)-thiolate complexes (Au-(I)-SR) are synthesized at room temperature using glutathione as both a reducing agent and capping ligand. The photoluminescence (PL) intensity and emission wave-length are found to be strongly affected by the pH environment during and post synthesis. Although there is no Au(0) core present in these complexes, Au(I)-SR exhibit PL which can be further enhanced through an aggregation-induced emission mechanism. The structures of these Au(I)-SR at each pH stage are carefully characterized. Using X-ray absorption fine structure, we further establish a relationship between the PL intensity and degree of aurophilic interactions. We find that the luminescence of Au(I)-SR is tunable over a wide pH range with good reversibility.