Lanthanide-induced shifts in the carbon-13 nuclear magnetic resonance spectra of some ketones, alcohols, and amines. An analysis of contact, pseudo-contact, and complex-formation contributions to the observed shifts
- 1 January 1974
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 2
- No. 10,p. 1202-1206
- https://doi.org/10.1039/p29740001202
Abstract
The lanthanide-induced shifts in the carbon-13 n.m.r. spectra of some ketones, alcohols, and amines are reported. The shifts produced upon complex formation with diamagnetic La(dpm)3 are relatively large for carbonyl carbons of ketones, and significant for oxygen-bonded carbons of alcohols, and carbons α to the C–N bond of primary amines (C–C–N); appropriate corrections must therefore be made to the measured shifts produced by paramagnetic lanthanide ions. Contact contributions to the 13C shifts in the compounds examined are generally larger in amines than alcohols or ketones, pseudo-contact shifts normally being dominant in the last two classes of compound. For quantitative structural 13C work with shift reagents, Yb(dpm)3 is recommended as it minimises contact contributions without causing adverse line broadening.Keywords
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