Premium
Pyramidal nitrogen inversion hindered by a strong intramolecular hydrogén bond in 2‐diethylaminomethylphenols
Author(s) -
Denisov G. S.,
Gindin V. A.,
Golubev N. S.,
Koltsov A. I.,
Smirnov S. N.,
Rospenk Koll Sobczyk M. A. And L.
Publication year - 1993
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260311116
Subject(s) - chemistry , intramolecular force , nitrogen inversion , nitrogen , inversion (geology) , hydrogen bond , molecule , enthalpy , nuclear magnetic resonance spectroscopy , computational chemistry , photochemistry , crystallography , stereochemistry , organic chemistry , thermodynamics , paleontology , physics , structural basin , biology
In the 1 H NMR spectra of 2‐diethylaminomethyl‐3,4,6‐trichlorophenol (1) below 260 K, an additional splitting of the CH 2 signal was found, which can be ascribed to the hindered nitrogen inversion. In the molecule of the O ‐methylated derivative (2) this process is fast (on the NMR time‐scale) down to 150 K. The frequencies and the activation parameters of the nitrogen inversion in (1) were measured by DNMR, which indicated that the inversion requires a preliminary stage of breaking an intramolecular hydrogen bond. The activation enthalpy, δ H inv ‡ , of the inversion stage was evaluated as 28.5 ± 6.7 kJ mol −1 .