Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 10: Poster: Charged Soft Matter
CPP 10.7: Poster
Montag, 14. März 2011, 17:30–19:30, P2
Partial oxidation of Cu(I) based ionic liquids under aerobic conditions monitored by XPS — •Angela Ulbrich1, Marcel Himmerlich1, Marion Stricker2, Jörg Sundermeyer2, and Stefan Krischok1 — 1Institut für Physik and Institut für Mikro- und Nanotechnologien, TU Ilmenau, PF 100565, 98684 Ilmenau, Germany — 2Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg, Germany
Copper (I) based ionic liquids (ILs) like [Cu(Imn)2][CuX2] (Imn = 1-alkylimidazole; X = Cl, Br) have great potential for catalytic applications, e.g. the synthesis of dimethyl carbonate from MeOH, CO and O2 [1]. The [Cu(Im6)2][CuX2] ILs are liquid at room temperature. Detailed knowledge of the electronic structure and their behaviour under environmental conditions is quite important. Due to the low vapour pressure of ILs it is possible to analyse their properties under ultra high vacuum conditions. The electronic structure of these ILs was investigated using X-ray photoelectron spectroscopy (XPS). We have handled these oxygen-sensitive ILs under inert atmosphere and besides the expected elements only traces of oxygen were detected. Generally, strong chemical modifications of [Cu(Im6)2][CuX2] were identified at the near surface region after exposure to air. The oxygen amount increased strongly and two different oxidation states were observed. Also shake-up structures near the Cu 2p core level appeared in the spectra, which are indicative for Cu(II) ions. Even after long exposure to environmental conditions, copper is not completely transformed to Cu(II).
[1] M. Stricker et al., Green Chem. 2010, 12, 1589-1598.