Infrared spectroscopic study of the effects of different cations on NN-dimethylacetamide and fully deuterated NN-dimethylformamide

Abstract

The infrared spectra of NN-dimethylacetamide and fully deuterated NN-dimethylformamide complexed to a variety of metal cations in propan-1-ol have been measured.

The OC—N stretching and O—C—N bending frequencies were found to vary systematically with the electrostatic potential at the surface of the cation. The O—CN stretching frequency was primarily determined by the electronic structure of the complexed cation.

The data indicate that complexation takes place via the carbonyl oxygen for all of the complexes studied, and support the idea of electrostatic stabilization of negative charge at the carbonyl oxygen by cations.

The data also indicate that back bonding may take place between transition metal cations and complexed amides.