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Ab‐initio study of the mechanism for the reaction of a primary amine with an aldehyde group
Author(s) -
Abdulnur S. F.
Publication year - 2009
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.560180716
Subject(s) - chemistry , lone pair , aldehyde , amine gas treating , formaldehyde , ab initio , electrophile , hydronium , dimethylamine , ammonia , primary (astronomy) , proton , trimethylamine , quantum tunnelling , computational chemistry , photochemistry , ion , organic chemistry , molecule , materials science , catalysis , physics , optoelectronics , quantum mechanics , astronomy
The interaction of a primary amine with an aldehyde group to form the enolamine RHN—C(OH)HR' is investigated for the simplified system of ammonia and formaldehyde, using the sto‐3 G method. The usually accepted approach in which the NH 3 lone electron pair points toward the electrophilic aldehydic C atom in a direction perpendicular to the plane of formaldehyde is found to be associated with a strong repulsive potential for N—C separation R 1 , less than ∼3 Å. A concomitant tunneling of a proton from a solution hydronium ion to the carbonyl oxygen, which increases as R 1 decreases, is shown to result in an energywise downhill closer approach of NH 3 to R 1 = 1.6 Å, thus leading to the formation of the enolamine. The electronic charge transferred from NH 3 in this system is also discussed.