Premium
Solvent Effect on the Protonation of Acetylene and Ethylene – Continuum Solvent Quantum Chemical Calculations
Author(s) -
Bagno Alessandro,
Modena Giorgio
Publication year - 1999
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199911)1999:11<2893::aid-ejoc2893>3.0.co;2-t
Subject(s) - protonation , chemistry , acetylene , endothermic process , ethylene , ab initio , solvent effects , solvent , computational chemistry , aqueous solution , exothermic reaction , solvation , natural bond orbital , ab initio quantum chemistry methods , photochemistry , organic chemistry , density functional theory , ion , molecule , catalysis , adsorption
The protonation of acetylene and ethylene (yielding the vinyl and ethyl cation, respectively) was investigated computationally by ab initio calculations [B3LYP/6–31G(d,p)], in the gas phase and in water, as modeled by the IPCM and SCIPCM continuum methods. The structures and NBO atomic charges were thus determined for the neutral bases and their protonated forms, while the comparison of gas‐phase and aqueous basicities afforded the hydration energies of the protonated bases. It was found that the aqueous protonation of acetylene is more endothermic than that of ethylene by 5 kcal/mol, owing to the lower intrinsic basicity of the former (by 7.4 kcal/mol), which is only partly compensated for by the more exothermic hydration (by 3.8 kcal/mol) of the vinyl cation.