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An ab initio molecular orbital study of the deprotonation of amines
Author(s) -
Hopkinson Alan C.,
Lien Min H.
Publication year - 1978
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560130308
Subject(s) - deprotonation , chemistry , ab initio , molecular orbital , substituent , basis set , ion , ab initio quantum chemistry methods , computational chemistry , crystallography , medicinal chemistry , molecule , density functional theory , organic chemistry
The geometries of the amines NH 2 X and amido anions NHX − , where X = H, CH 3 , NH 2 , OH, F, C 2 H, CHO, and CN have been optimized using ab initio molecular orbital calculations with a 4‐31G basis set. The profiles to rotation about the NX bonds in CH 3 NH − , NH 2 NH − , and HONH − are very similar to those for the isoprotic and isoelectronic neutral compounds CH 3 OH, NH 2 OH, and HOOH. The amines with unsaturated bonds adjacent to the nitrogen atoms undergo considerable skeletal rearrangement on deprotonation such that most of the negative charge of the anion is on the substituent. The computed order of acidity for the amines NH 2 X is X = CN > HCO > F ≈ C 2 H > OH > NH 2 > CH 3 > H and for the reaction NHX − + H + → NH 2 X the computed energies vary over the range 373–438 kcal/mol.