STUDY OF THE PROTONATION/DEPROTONATION SEQUENCE OF TWO POLYAMINES: BIS-[(2S)-2-PYRROLIDINYLMETHYL] ETHYLENEDIAMINE AND SPERMIDINE BY 1H AND 13C NUCLEAR MAGNETIC RESONANCE

ABSTRACT In this paper we describe the study of protonation/deprotonation of two polyamines: bis-[(2S)-2-pyrrolidinylmethyl]ethylenediamine (tetra) and spermidine (Spd). A new synthetic route was established for the synthesis of tetra, which structure was confirmed by IR, elemental analyzes, 1H-NMR, 13C-NMR(Pendant) and 2D-NMR (COSY, 13C-1H HETCOR and HMQC) spectra. The protonation/deprotonation sequence studies of tetra and Spd were determined by potentiometric and NMR methods. For the NMR studies, the tetra and Spd samples were dissolved in D2O and the pD adusted with NaOD. The protonation/deprotonation sequences of tetra and Spd were determined by means of the values and the variations of the hydrogen atom and 13C NMR chemical shifts as a function of hydrogen atom pD. The variation of δ 1H with pD clearly showed that the first protonation of tetra occurs at the pyrrolidine nitrogen atoms and the second protonation occurs at the ethylenediamine nitrogen atom. The analysis of the 13C-NMR spectra confirme...