13C nuclear magnetic resonance study of some aliphatic polyamines

The 13C n.m.r. spectra of the unprotonated and fully protonated forms of ethylenediame (en), N-(2-aminoethyl)propane-1,3-diamine (2,3-tri), 2,2′-ethylene di-iminobis(ethylamine)(trien), 2,2′-trimethylenedi-iminobis (ethylamine)(2,3,2-tet), and 3,3′-trimethylenedi-iminobis(propylamine)(3,3,3-tet) are reported, together with those of the unprotonated forms of 2,2′-iminobis(ethylamine)(dien), 3,3′-iminobis(propylamine)(dpt), 2,2′-iminodiethylenedi-iminobis(ethylamine)(tetren), and 2,2′,2″-nitrilotris(ethylamine)(tren). A full assignment of the chemical shifts is proposed, based on a two-term empirical relationship employing ‘amine shift parameters’π and π+.