Structural and spectroscopic investigations of non‐planar tris(dialkylamino)cyclopropenium cations

The mixed triaminocyclopropenium cation bis(diisopropylamino)dimethylaminocyclopropenium was prepared from bis(diisopropylamino)chlorocyclopropenium by reaction with dimethylamine. It was isolated as the perchlorate salt and found to have a distorted structure in the solid state. Tris(diisopropylamino)cyclopropenium was prepared by reaction of pentachlorocyclopropane with diisopropylamine in a refluxing dichloroethane solution for 2 days. The solid state structure was found by X‐ray crystallography to have two planar amino groups and one pyramidal amino group, however, the 1H‐NMR and infrared solution spectra show equivalent isopropyl groups in solution. The compounds were also characterised by Raman and infrared spectroscopy. Additionally, a new polymorph of [C3(NMe2)3]ClO4 is described as well as the X‐ray structure of bis(diisopropylamino)cyclopropenone.