Dissociation of copper(I) and silver(I) cluster ions of fatty acids: Ag_(2)H~(+) as a marker for double bonds.

摘要

Group XI metals show similar behaviour when mediating dissociation of fatty acids and the differences can be directly related to the physical properties of those metals. Two competing channels, M_(2)H~(+) formation and hydrocarbon chain fragmentation, are observed. M_(2)H~(+) abundance can be related to the ionization energy of the three metals, abundant with Ag (IE velence 7.58 eV), less so with Cu (IE velence 7.73 eV) and not observed with Au (IE velence 9.23 eV). Theoretical calculations by Flurer et al. (JACS, 1991) show that both Cu_(2)H~(+) and Ag_(2)H~(+) have the same linear structure (M-H-M), consistent with our non-observations of (Cu_(2))~(+) or (Ag_(2))~(+). This is also consistent with our observed role of ionization energy of the metal in the formation of M_(2)H~(+) ion.