An ab initio study of the reaction of propargyl cation with water

• Published in: Journal of molecular structure. Theochem Vol. 683; no. 1; pp. 81 - 87
• Main Authors: López, R., del Río, E., Menéndez, M.I., Sordo, T.L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 10.09.2004
• Subjects: Ab initio calculations; C 3H 5O + complexes; Propargyl cation; Statistical thermodynamics analysis; Statistical thermodynamics analysis; Propargyl cation; Ab initio calculations; C 3H 5O + complexes
• ISSN: 0166-1280; 1872-7999
• DOI: 10.1016/j.theochem.2004.06.015

The reaction of propargyl cation with water was investigated at the CCSD(T)/6-311+G(2df,2p)//MP2-FULL/6-31+G(d,p) theory level by performing a statistical thermodynamics analysis of the theoretical results. We located five endothermic reaction channels, H 2CCC+H 3O + and four c-C 3H 2+H 3O + by 47.8 and 35.7 kcal/mol in Gibbs energy, respectively, and eight exothermic reaction channels, four c-C 3H 3 ++H 2O (−26.5 kcal/mol), two C 3H 3O ++H 2O (−43.4 kcal/mol), and two C 3H 3·OH 2 + (−56.0 kcal/mol). The rate determining TSs located are clearly less stable with respect to reactants than those previously reported for the process H 2CCCH ++NH 3 thus explaining the low experimental yield found for the reaction with water (0.3%) compared with that for the reaction with ammonia (87%). By assuming that only the H 2CCC+H 3O +, C 3H 3O ++H 2, and C 3H 3·OH 2 + channels are competitive, the product distribution experimentally determined (40% of H 2CCC+H 3O +, 30% of C 3H 3O ++H 2, and 30% of C 3H 3·OH 2 +) can be rationalized.