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The structure and proton affinity of N‐benzyl‐N‐(allenyl)trifluoromethanesulfonamide: FT‐IR, DFT and ab initio study, NBO analysis
Author(s) -
Shainyan B. A.,
Chipani. N.,
Oznobikhina L. P.,
Danilevich Yu. S.
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.3147
Subject(s) - chemistry , lone pair , natural bond orbital , intramolecular force , protonation , proton affinity , ab initio , computational chemistry , nitrogen atom , atoms in molecules , density functional theory , atom (system on chip) , molecule , group (periodic table) , crystallography , medicinal chemistry , stereochemistry , organic chemistry , computer science , embedded system , ion
The first N‐allenyl derivative of trifluoromethanesulfonamide, N‐benzyl‐N‐(allenyl)trifluoromethanesulfonamide ( 1 ), was studied experimentally by the FT‐IR spectroscopy and theoretically at the DFT and MP2 levels of theory. The intramolecular interaction of the nitrogen atom with the triflyl and the allenyl group was studied in comparison with the analogously substituted vinyl derivatives. Compound 1 in heptane solution at 295–183 K exists as an equilibrium mixture of conformational isomers. Protonation at different basic sites in a series of reference molecules is studied theoretically. The central C 2 atom of the allenyl group in 1 has the highest proton affinity, which is 16 kcal/mol higher than in the N‐vinyl analogues. The relative ability of the allenyl and vinyl groups to conjugation with an electron‐rich and electron‐deficient nitrogen atom lone electron pair is discussed. From the NBO analysis, the conjugation of the nitrogen lone electron pair with the allenyl group is much stronger than with the vinyl group. Copyright © 2013 John Wiley & Sons, Ltd.