Observing the real time formation of phosphine-ligated gold clusters by electrospray ionization mass spectrometry
Early stages of the reduction and nucleation of solution-phase gold clusters are largely unknown. This is due, in part, to the high reaction rates and the complexity of the cluster synthesis process. Through the addition of a diphosphine ligand, 1-4,Bis(diphenylphosphino)butane (L4) to the gold precursor, chloro(triphenylphosphine) gold(I) (Au(PPh3)Cl), in methanol organometallic complexes of the type, [Au(L4)x(L4O)y(PPh3)z]+, are formed. These complexes lower the rate of reduction so that the reaction can be directly monitored from 1 min to over an hour using on-line electrospray ionization mass spectrometry (ESI-MS). Our results indicate that the formation of Au8(L4)42+, Au9(L4)4H2+ and Au10(L4)52+ cationic clusters occurs through different reaction pathways that may be kinetically controlled either through the reducing agent concentration or the extent of oxidation of L4. Through comparison of selected ion chronograms our results indicate that Au2(L4)2H+ may be an intermediate in the formation of Au8(L4)42+and Au10(L4)52+ while a variety of chlorinated clusters are involved in the formation of Au9(L4)4H2+. Additionally, high-resolution mass spectrometry was employed to identify 53 gold containing species produced under highly oxidative conditions. New intermediate species are identified which help understand how different gold cluster nuclearities can be stabilized during the growth process.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1371982
- Report Number(s):
- PNNL-SA-124379; PPCPFQ; 49272; KC0302020
- Journal Information:
- Physical Chemistry Chemical Physics. PCCP (Print), Vol. 19, Issue 26; ISSN 1463-9076
- Publisher:
- Royal Society of Chemistry
- Country of Publication:
- United States
- Language:
- English
Similar Records
Investigating the Synthesis of Ligated Metal Clusters in Solution Using a Flow Reactor and Electrospray Ionization Mass Spectrometry
ESI-MS Identification of the Cationic Phosphine-Ligated Gold Clusters Au1-Au22: Insight into the Gold-Ligand Ratio and Abundance of Larger Clusters