1,8-Bis(dimethylamino)naphthyl-2-ketimines: Inside vs outside protonation.

ABSTRACT: The structure and protonation behaviour of four ortho-arylketimines of 1,8-bis(dimethylamonio)naphthalene with a different number of methoxy groups in an aromatic substituent were investigated in solution by NMR (acetone, DMSO, MeCN), in solid state by X-ray analysis and in the gas phase by DFT calculations. Both mono- and diprotonated species were considered. It has been shown that E-isomers of neutral imines can be stabilised by an intramolecular C=N-H···OMe hydrogen bond with a neighbouring methoxy group. Electron-donating OMe groups dramatically increase the basicity of the imino nitrogen, forcing the latter to abstract a proton from the proton sponge moiety in monoprotonated forms. The participation of the out-inverted and protonated 1-NMe2 group in the Me2N-H···NH=C hydrogen bond is

SUBMITTER: Antonov AS 

PROVIDER: S-EPMC6278759 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature