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Temperature dependence of 13 C nuclear magnetic shielding in some aliphatic alcohols
Author(s) -
Jackowski K.,
Raynes W. T.
Publication year - 1980
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/mrc.1270130609
Subject(s) - tetramethylsilane , electromagnetic shielding , van der waals force , chemistry , atmospheric temperature range , temperature coefficient , methanol , hydrogen bond , protonation , hydrogen , analytical chemistry (journal) , thermodynamics , materials science , organic chemistry , molecule , physics , composite material , ion
The 13 C nuclear shielding in methanol, ethanol and isopropanol has been measured over the temperature range 186–325 K. Corrections to the observed shifts have been made to allow for the temperature dependence of the shielding of the external tetramethylsilane reference and for the temperature dependence of the bulk susceptibility effects in the alcohols. The results show that the temperature dependence of 13 C shielding in the liquid alcohols is smaller than that in tetramethylsilane. By comparison both with temperature coefficients of compounds not involving hydrogen bonding and with N ‐protonation studies, it is inferred that the reduction of hydrogen bonding which occurs in the liquid alcohols as the temperature is raised has very little effect on the 13 C shielding. It is the change in the van der Waals forces which predominates in determining the temperature coefficient.