Premium
Intramolecular interactions and spin–lattice relaxation times of methyl groups
Author(s) -
Ng Soon
Publication year - 1983
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/omr.1270210113
Subject(s) - steric effects , intramolecular force , methyl group , chemistry , carbon atom , alkyl , crystallography , hydrogen bond , hydrogen , carbon fibers , relaxation (psychology) , stereochemistry , photochemistry , molecule , materials science , organic chemistry , psychology , social psychology , composite number , composite material
The carbon T 1 values of the alkyl substituents of various compounds have been measured. The salient observation is that the terminal methyl carbon of the n ‐propyl or a three‐carbon chain bonded to an electronegative atom X(or an electron‐donating group) has a reduced T 1 value. A net attractive interaction between the methyl hydrogen atoms and X in the gauche conformation is invoked to account for the observed result. In chains longer than three carbons that are not firmly anchored at one end, the γ steric interaction is suggested to be the main steric interaction that causes the reduced T 1 value observed for the terminal methyl carbon.