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Amino, ammonio and aminioethenes: a theoretical study of their structure and energetics
Author(s) -
Miranda Margarida S.,
Esteves da Silva Joaquim C. G.,
Castillo Alvaro,
Frank Aaron T.,
Greer Alexander,
Brown Jodian A.,
Davis Brittny C.,
Liebman Joel F.
Publication year - 2013
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3140
Subject(s) - chemistry , isodesmic reaction , standard enthalpy of formation , proton affinity , protonation , ab initio , enthalpy , computational chemistry , thermochemistry , energetics , ionization energy , mndo , standard enthalpy change of formation , electron affinity (data page) , ionization , adiabatic process , ion , thermodynamics , molecule , organic chemistry , physics
We have performed high level ab initio quantum mechanical calculations for aminoethene and the three isomeric 1,1‐ ( Z )‐ or ( E )‐1,2‐diaminoethenes as well as their singly and doubly charged cations derived by loss of electrons and/or upon protonation. Gas phase molecular structures were computed at the MP2/6‐311 + G(3df,2p) level. Standard molar enthalpies of formation in the gas phase, at T = 298.15 K, were estimated using the G3 composite method and atomization, isodesmic and homodesmotic reactions. Other energetic parameters were also calculated at the G3 level: proton affinities, basicities and adiabatic ionization enthalpies. Theoretical and experimental data are compared. The reported experimental data refer only to aminoethene wherein the standard molar enthalpy of formation has a considerable uncertainty, although the molecular structure is well established. There are no such data, neither structural nor thermochemical, for any of the three isomeric diaminoethenes. Isoelectronic comparisons are made. For example, the diprotonated diaminoethenes are isoelectronic to isobutene and ( Z )‐ and ( E )‐butene, while the doubly ionized diaminoethenes are likewise related to trimethylenemethane and 1,3‐butadiene. Copyright © 2013 John Wiley & Sons, Ltd.