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Updated: Jul 9, 2026

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
A new NMR approach for the assignment of symmetric isomers
Lodovico Lunazzi1, Andrea Mazzanti
1Department of Organic Chemistry, A. Mangini University of Bologna, Viale Risorgimento, 4 Bologna 40136, Italy.
Abstract:
Irradiation of the (13)C satellite (1% natural abundance) of the NMR (1)H signals yields NOE effects on the spatially close hydrogens of the same isotopomer but not on the hydrogens of the 99% isotopomer having only (12)C atoms. In a DPFGSE-NOE sequence, the latter signals are completely canceled, and it is possible, therefore, to detect NOE effects experienced by isochronous lines that would not be otherwise observable. This allows the structural assignments of symmetric isomers to be unambiguously obtained. Examples are reported for the cases of the cis and trans dimethylstilbene, cis and trans stilbeneoxide, 2,5- and 3,4-dimethylthiophene, 1,8- and 1,5-dimethylnaphthalene, syn and anti 1,2-bis(2-methyl-1-naphthyl)benzene, 1,3-cyclooctadiene, and cycloheptatriene.
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