An Experimental and Theoretical Investigation of Gas-Phase Reactions of Ca2+ with Glycine

✍ Scribed by Inés Corral; Otilia Mó; Manuel Yáñez; Jean-Yves Salpin; Jeanine Tortajada; Damian Moran; Leo Radom

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 932 KB
• Volume: 12
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200600127

✦ Synopsis

Abstract

The gas‐phase reactions between Ca^2+^ and glycine ([Ca(gly)]^2+^) have been investigated through the use of mass spectrometry techniques and B3‐LYP/cc‐pWCVTZ density functional theory computations. The major peaks observed in the electrospray MS/MS spectrum of [Ca(gly)]^2+^ correspond to the formation of the [Ca,C,O~2~,H]^+^, NH~2~CH~2~^+^, CaOH^+^, and NH~2~CH~2~CO^+^ fragment ions, which are produced in Coulomb explosion processes. The computed potential energy surface (PES) shows that not only are these species the most stable product ions from a thermodynamic point of view, but they may be produced with barriers lower than for competing processes. Carbon monoxide is a secondary product, derived from the unimolecular decomposition of some of the primary ions formed in the Coulomb explosions. In contrast to what is found for the reactions of Ca^2+^ with urea ([Ca(urea)]^2+^), minimal unimolecular losses of neutral fragments are observed for the gas‐phase fragmentation processes of [Ca(gly)]^2+^, which is readily explained in terms of the topological differences between their respective PESs.