C. Nather et al., CRYSTAL-STRUCTURE OF N,N,N',N'-TETRAISOPR OPYL-P-PHENYLENE-DIAMMONIUMDICHLORIDE AND TRAISOPROPYL-P-PHENYLENE-BIS(TETRACHLOROALUMINATE), Monatshefte fuer Chemie, 128(8-9), 1997, pp. 841-848
Protonation of the sterically overcrowded N,N,N',N'-tetraisopropyl-p-p
henylenediamine leads to a significant shortening of the C-N bond leng
ths of 7 pm as well as to a widening of the phenyl ipso-angle to 122 d
egrees. All structural changes can be attributed to the twisted diisop
ropylammonium substituents and their electron acceptor properties.