Generation of Au2Cl2n+1 (n = 1-3) cluster ions by laser desorption/ionization mass spectrometry

Abstract

Gold chloride clusters were generated from an aqueous solution of gold-hydrochloric acid deposited onto the target plate using laser desorption/ionization (LDI) on a commercial matrix assisted laser desorption/ionization –time of flight (MALDI-TOF) mass spectrometric instrument. In our experimental conditions negative mode of LDI mass spectra provided the most valuable informations. The mass peaks at m/z about 339, 499, 571, 641, were assigned to AuCl4-, Au2Cl3-, Au2Cl5-, Au2Cl7-cluster ions, respectively. The Au2Cl5-and Au2Cl7-clusters are detected for the first time in this work. This research showed that LDI MS, thanks to its easy experimental procedure, a soft ionization technique which may be a useful characterization tool in the chemistry of heterogeneous gold clusters.