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Computational and dynamic NMR investigation of 2,2‐dimesityl‐1,1,1,3,3,3‐hexamethyltrisilane
Author(s) -
Winchester William R.,
Seymour Jenna
Publication year - 2020
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.4991
Subject(s) - chemistry , carbon 13 nmr satellite , carbon 13 nmr , density functional theory , silicon , crystallography , nuclear magnetic resonance spectroscopy , bond length , proton nmr , computational chemistry , crystal structure , nuclear magnetic resonance , fluorine 19 nmr , stereochemistry , organic chemistry , physics
The structure and rotational barrier for the mesityl‐silicon bond of 2,2‐dimesityl‐1,1,1,3,3,3‐hexamethyltrisilane have been investigated by 1 H‐ and 13 C‐variable temperature nuclear magnetic resonance (NMR) as well as by density functional theory structural calculations. The calculations show that the lowest energy structure has C 2 symmetry with nonequivalent ortho methyl groups, consistent with the crystal structure and solution NMR. The nonequivalent ortho methyl groups exchange through a C s transition state with a calculated relative free energy of 11.0 kcal mol −1 . The barrier for this rotation found by dynamic NMR is 13.4 ± 0.2 kcal mol −1 at 298 K.