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The combined effects of two chlorine substituents and the non‐additivities of chemical shifts in aliphatic dichloro esters
Author(s) -
Pitkänen Maija
Publication year - 1982
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.1270180311
Subject(s) - additive function , chemistry , chlorine , substituent , chemical shift , propanoic acid , chlorine atom , medicinal chemistry , carbon fibers , organic chemistry , computational chemistry , stereochemistry , mathematical analysis , materials science , mathematics , composite number , composite material
Carbon‐13 NMR spectra were measured for 25 methyl esters of aliphatic dichlorocarboxylic acids for substituted propanoic to hexanoic acids. Observed 13 C shifts are compared with calculated shift values obtained from the shifts of the corresponding monochloro esters by applying a simple sum method. The greatest failures from additivity are observed for αβ and αα substituted carbons. The combined effects of two chlorine substituents were determined, and compared with those obtained from chlorine substituent effects in monochloro esters by assuming additivity. The trends displayed by the combined effects, and also by the non‐additivity effects, are discussed.