Mixed dithiolate durene-DT and monothiolate phenylethanethiolate protected Au130 nanoparticles with discrete core and core-ligand energy states.

A new type of gold nanoparticle with interesting energetics has been created by employing a mixture of dithiol durene (Durene-DT) and monothiol phenylethanethiol (PhC2S) in the synthesis. The average composition of these mixed thiolate clusters is characterized to be Au(130)(Durene-DT)(29)(PhC2S)(22). Continuous quantized core charging behaviors were observed at lower potentials in voltammetric measurements, while ligand reaction and core-ligand interactions were observed at higher potentials. The absorbance spectrum displays discrete absorption bands at ca. 355, 490, 584, and 718 nm. The electrochemical and absorbance features are correlated through the determined energy states and charging energy. Broad near-IR luminescence was observed, associated with significant relaxation of excitation energy. Such interesting optical and electrochemical properties are attributed to the nanoparticle core size, ligand composition, and core-ligand charge delocalization determined by the dithiolate molecular structure.