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Density functional theory calculations of 17 O and 13 C NMR chemical shifts for aromatic acyl chlorides
Author(s) -
Chao Ito,
Chen KoWen,
Hwang TsongSong,
Liu KwangTing
Publication year - 2001
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.396
Subject(s) - chemistry , chemical shift , substituent , aryl , density functional theory , computational chemistry , gas phase , aromaticity , proton nmr , atom (system on chip) , molecule , medicinal chemistry , stereochemistry , organic chemistry , alkyl , computer science , embedded system
Density functional theory (DFT) at the B3LYP/6–31 + G(d,p)//B3LYP/6–31G(d) level was used to calculate 17 O and 13 C NMR chemical shifts of the carbonyl group of aromatic acyl chlorides 1a – n . The aryl groups included substituted phenyl, furyl, thienyl and naphthyl. The calculated 17 O chemical shifts correlated well with the experimental values and with Hammett‐type σ + constants. Therefore, in many cases it is possible to deduce σ + constants of substituted aryl groups via gas‐phase calculation of 17 O chemical shifts of the carbonyl groups. The σ + values obtained in the gas‐phase calculation show the intrinsic property of substituents, so they provide a good reference set for systematic comparison to evaluate the effect of the environment. Furthermore, the concept of n–π* mixing can be used to understand the sensitivity of the O and Cl atoms and the insensitivity of the C atom towards substituent effects in aromatic acyl chlorides. Copyright © 2001 John Wiley & Sons, Ltd.