Thermochemistry and unimolecular reactivity of protonated α,ω-aminoalcohols in the gas phase

Abstract

Competitive deamination and dehydration of protonated α,ω-aminoalcohols (1,2-aminoethanol ( 1), 1,3-aminopropanol ( 2), 1,4-aminobutanol ( 3) and 1,5-aminopentanol ( 4)) in the gas-phase has been examined by both tandem mass spectrometry experiments including metastable ions decompositions and collisional activation (CA) techniques and molecular orbital calculations. For all the precursor molecules 1– 4, CA experiments demonstrate that the low energy product ions are either a protonated cyclic amine or a protonated cyclic ether. The mechanisms of the internal nucleophilic substitution reactions leading to these products have been detailed at the MP2/6-31G ∗ level of theory. The thermochemistry associated with the initial protonation process of 1– 4 has been examined up to the G2(MP2,SVP) level.