Published in Henry Rzepa's Blog

An earlier post investigated large anomeric effects involving two oxygen atoms attached to a common carbon atom. A variation is to replace one oxygen by a nitrogen atom, as in N-C-O. Shown below is a scatter plot of the two distances to the common carbon atom derived from crystal structures. You can see some entries for which the C-O bond length is shorter than normal and the C-N distance very much longer than normal;

References

Condensed Matter PhysicsGeneral Materials ScienceGeneral Chemistry

O-vs. N-protonation of 1-dimethylaminonaphthalene-8-ketones: formation of aperiN–C bond or a hydrogen bond to the pi-electron density of a carbonyl group

Published in CrystEngComm
Authors Nerea Mercadal, Stephen P. Day, Andrew Jarmyn, Mateusz B. Pitak, Simon J. Coles, Claire Wilson, Gregory J. Rees, John V. Hanna, John D. Wallis

Peri-amino-naphthylketones protonate onOorNforming a longperi-N–C bond or a hydrogen bond to the ketone's π-density.