Gas-phase reactivity of Cu⁺ and Ag⁺ with glycerol: An experimental and theoretical study

The reactions between Cu+ and Ag+ metal cations and glycerol (CH2OH-CHOH-CH2OH) in the gas phase have been investigated by means of mass spectrometry and B3LYP density functional calculations. The [glycerol,X]+ (X = Cu, Ag) complexes are formed in the ion source. The structures of several coordinations of the metal cation to glycerol have been determined at the B3LYP level. Calculations show that although the preferred attachment for Cu+ involves a chelation between two hydroxyl oxygens of glycerol, a tricoordinated structure is obtained for Ag+ complexation. The MIKE spectra of the [glycerol,X]+ ions have also been analyzed and show that both complexes undergo fragmentation by different pathways. For [glycerol,Ag]+, the most important fragmentation corresponds to the loss of glycerol process. However, this process is not observed for [glycerol,Cu]+, where the major fragmentation corresponds to the elimination of water. The possible mechanisms leading to these fragmentations, and others observed only to a minor extent, have been studied using labeled glycer(ol-d3) and calculations performed at the B3LYP level.