Experimental Investigation of the Stability of AuCl (n = 1-5; m = 1, 3, 5, 7) Clusters by Laser Desorption/Ionization Mass Spectrometry.

The stability of gold chloride clusters is an important topic in catalysis and nanomaterials, but experimental data are missing. Here, fourteen different clusters were obtained simultaneously using laser desorption/ionization mass spectrometry and were identified as AuCl (n = 1-5; m = 1, 3, 5, 7) or AuCl, AuCl, AuCl, AuCl and AuCl. Consequently, the effects of laser intensity on their stability were evaluated, considering differences in the AuCl unit or the number of Cl atoms. For the AuCl and AuCl groups, the relative intensity of the clusters decreased with each additional AuCl unit as the laser intensity increased. AuCl clusters showed a different trend in relative intensities: AuCl > AuCl > AuCl > AuCl. The mononuclear AuCl showed the highest stability, which is consistent with their "superhalogen" character. In the AuCl clusters, AuCl with Au (III)-Au(I) interaction was more stable at lower laser intensities, while AuCl with Au(I)-Au(I) bonds became more dominant at higher intensities. Among the AuCl, AuCl clusters, those with purely "aurophilic" interactions became increasingly stable with increasing laser intensity. These results emphasize the importance of bond type and cluster size for the stability of gold chloride clusters at different laser intensities.