Crystal and Molecular Structure of Ph3P+-CH = CH-NHC6H3(2-O-)(4-NO2)

Treatment of Ph₃P⁺-CH = CH-NHC₆H₃(2-OH)(4-NO₂)]Cl^- with ethanolic KOH leads to proton abstraction not from nitrogen, but from oxygen to give a betaine-type compound Ph₃P⁺-CH = CHNHC₆H₃ · (2-O^-)(4-NO₂). Its structure was proved by means of X-ray diffraction. The C = C distance 1.341(3) Å] unambiguously points to a double bond. Single crystals of the betaine are monoclinic, space group P2(1)/c; unit cell parameters: a 9.028(4), b 14.066(6), and c 18.799(10) Å; 90, 76.23(4), and 90°. The unit cell contains two dimers bound by strong inter- and intermolecular hydrogen bonds. Previously published IR and ¹H NMR data do not contradict the betaine structure of the compound obtained.