Referenced in: none

Automatically associated channels: Kir2.3 , Slo1

Title: Gas phase reactions between acetylene radical cation and water. energies, structures and formation mechanism of C2H3O+ and C2H4O+* ions.

Authors: Paul O Momoh, Enli Xie, Samuel A Abrash, Michael Meot-Ner Mautner, M Samy El-Shall

Journal, date & volume: , 2008 Jul 10 , 112, 6066-73

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/18563873

Abstract
Reactions of the acetylene radical cation (C2H2(+*)) with H2O were investigated using ion mobility mass spectrometry. The primary products are the C2H3O(+) and C2H4O(+*) ions, produced with an overall rate coefficient k(300 K) = 2(+/-0.6) x 10(-11) cm(3) s(-1) that increases with decreasing temperature. The C2H4O(+*) (adduct) vs C2H3O(+) (H loss) ratio also increases with decreasing temperature, and with increasing third-body pressure. Ab initio calculations on the products showed seven stable C2H3O(+) isomers and eleven stable C2H4O(+*) isomers. In the C2H4O(+*) adduct channel, the reactivity and energetics suggest that the adduct is the H2C=CHOH(+*) (vinyl alcohol) ion. In the C2H3O(+) channel, the H loss occurs exclusively from water. The C2H3O(+) product ion undergoes slow deprotonation by water to form H(+)(H2O)n clusters. The reactivity, combined with energetics, suggests that the protonated ketene CH2COH(+) is the most likely observed C2H3O(+) ion probably with some contribution from the cyclic c-CH2CHO(+) ion.