MESОIОNIC COMPOUNDS ‒ STRUCTURE AND NMR PARAMETERS

Аннотация

It has been shown, that ¹Н, ¹³С, ¹⁴N, ¹⁵N, ¹⁷О and ⁷⁷Se NMR are very successful techniques for the identification and investigation of potential valence tautomerism in all types of mesoionic compounds. Especially the combined use of ¹⁴N and ¹⁵N NMR studies has been shown to be very effective in solving structural problems. From ¹⁵N NMR it is possible to obtain accurate chemical shifts and spin-spin couplings, whereas the ¹⁴N NMR spectra provide us with nuclear relaxation and some chemical shift data. In particular ¹⁴N NMR is very useful for the identification of charged nitrogen atoms in molecules containing non equivalent nitrogen positions. This information is available from the relative ¹⁴N signal widths, which depend upon the rates of ¹⁴N relaxation, positively charged nitrogen atoms usually have rеlativеlly slow ¹⁴N relaxation rates thus giving rather sharp NMR signals. Some solid state, CР MAS, ¹³С and ¹⁵N NMR results are available for comparison with the solution NMR data.

How to Cite
Stefaniak, L.; Jaźwiński, J. Chem. Heterocycl. Compd. 1995, 31, 1027. [Khim. Geterotsikl. Soedin. 1995, 1180.]

For this article in the English edition, see DOI https://doi.org/10.1007/BF01165049