/sup 17/O NMR spectroscopy: torsion angle relationships in aryl carboxylic esters, acids, and amides

Journal Article · Tue Feb 17 23:00:00 EST 1987 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00238a013· OSTI ID:6970535

Baumstark, A L; Balakrishnan, P; Dotrong, M; McCloskey, C J; Oakley, M G; Boykin, D W

/sup 1/ /sup 7/O NMR spectroscopic data (natural abundance in acetonitrile at 75/sup 0/C) were obtained for the following series of electronically similar, sterically hindered compounds: aromatic methyl esters, aromatic carboxylic acids, and aromatic amides. Torsional angles were calculated by the molecular mechanics (MM2) method. Linear regression analysis of the estimated torsion angles and the /sup 17/O chemical shift data for each series yielded the following results (series, slope delta/degree, correlation coefficient): esters (C=O), 0.70, 0.997; esters (-0-), 0.43, 0.992; acids (-CO/sub 2/H), 0.56, 0.994; amides (C=O), 0.84, 0.942; N,N-dimethylamides (C=O), 0.6, 0.991. The results are discussed in terms of minimization of repulsive van der Waals interactions by rotation of the functional group out of the plane of the aromatic ring.

• Research Organization: Georgia State Univ., Atlanta
• OSTI ID: 6970535
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 109:4; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AMIDES
AROMATICS
CARBOXYLIC ACID ESTERS
CARBOXYLIC ACIDS
CHEMICAL SHIFT
DATA
ENERGY LEVELS
ESTERS
EVEN-ODD NUCLEI
EXCITED STATES
EXPERIMENTAL DATA
INFORMATION
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MEDIUM TEMPERATURE
MOLECULAR STRUCTURE
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN 17
OXYGEN ISOTOPES
RESONANCE
SPECTRA
STABLE ISOTOPES
STEREOCHEMISTRY
VIBRATIONAL STATES