Paper SS-TuP16
Preparative Mass Spectrometry: A Novel Approach for the Creation of Catalyst Materials

Tuesday, October 19, 2010, 6:00 pm, Room Southwest Exhibit Hall

Soft- and reactive landing of mass-selected ions onto surfaces is a unique approach for the highly controlled preparation of catalyst materials that are often inaccessible using conventional synthesis techniques. Mass selection allows polyatomic ions with known charge and chemical identity to be deposited onto surfaces under carefully controlled conditions, thereby avoiding purification steps which are typically necessary with traditional catalyst preparation methods. A new apparatus has been designed and assembled at PNNL that allows in situ reactivity and time of flight secondary ion mass spectrometry analysis of surfaces prepared or modified through soft- and reactive landing. The capabilities of this instrument for the preparation and analysis of catalyst materials are demonstrated for two different systems consisting of monolayer catalysts produced by the deposition of organometallic metal-salen and ruthenium bipyridine cations onto self assembled monolayer surfaces. It is shown that through soft landing of vanadium-salen cations and a proton donor it is possible to achieve proton mediated reactivity in an inert fluorinated monolayer that is normally only observed in highly acidic solutions. In addition, it is demonstrated that gas-phase ligand stripping may be used to generate highly reactive undercoordinated metal complexes which exhibit enhanced activity towards reactive landing in comparison to fully ligated species. The immobilized complexes, which are covalently bound to the surface, are shown to exhibit catalytic activity when exposed to gaseous reagents.