ABSTRACT
This chapter provides a review of the literature of the O nuclear magnetic resonance (NMR) spectroscopy of compounds containing oxygen bound to nitrogen and oxygen bound to oxygen. It deals with the relationships between structure and O chemical shift for organic compounds with oxygen bound to nitrogen. The chapter describes such relationships for organic compounds containing oxygen bound to oxygen. Nitro groups on benzene rings fused to electron-rich heterocycles were expected to have more single bond character for the nitrogen-oxygen bonds; thus their O chemical shift was expected to be upfield, compared to the value for nitrobenzene. The chemical shift for this group appears downfield from other systems with oxygen bound to nitrogen. This chapter deals with recent reports which have demonstrated the influence of electronic factors, steric factors, and hydrogen bonding on the O NMR chemical shift data for heteroaromatic N-oxides.
