Open AccessReactions of a Polyhalide Ionic Liquid with Copper, Silver, and Gold
Author(s) -
May Benjamin,
Lexow Matthias,
Taccardi Nicola,
Steinrück HansPeter,
Maier Florian
Publication year - 2019
Publication title -
chemistryopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 29
ISSN - 2191-1363
DOI - 10.1002/open.201800149
Subject(s) - ionic liquid , chemistry , inorganic chemistry , copper , x ray photoelectron spectroscopy , metal , iodide , passivation , trihalide , molybdenum , imidazole , organic chemistry , catalysis , halide , chemical engineering , layer (electronics) , engineering
The reactions of copper, silver, and gold with the imidazolium‐based polyhalide ionic liquid (IL) [C 6 C 1 Im][Br 2 I] were investigated by using X‐ray photoelectron spectroscopy (XPS), weight‐loss measurements, and gas‐phase mass spectrometry. All three Group 11 metals are strongly corroded by the IL at moderate temperatures to give a very high content of dissolved Cu I , Ag I , and Au I species. The IL–metal solutions are stable against contact with water and air. The replacement of imidazolium with inorganic sodium cations decreased metal corrosion rates by orders of magnitude. Our results clearly indicate metal oxidation by iodide from dibromoiodide anions to form molecular iodine and anionic [Br‐M I ‐Br] − (M=Cu, Ag, Au) complexes stabilized by imidazolium counterions. From experiments with a trihalide IL with imidazolium methylated at the 2‐position, we ruled out the formation of imidazole–carbene as a cause of the observed corrosion. In contrast to Group 11 metals, molybdenum is inert against the trihalide IL, which is attributed to surface passivation.