Polyamines. III. Spectroscopic properties of N,N-bis-(phthalimidopropyl)-N-octylamine and supramolecular interactions in its crystals

A new derivative of polyamine, N,N-bis-(phthalimidopropyl)-N-octylamine has been synthesized and its structure studied by X-ray diffraction, FTIR, 1H and 13C NMR spectroscopy. The B3LYP and DFT calculations have been carried out. The molecular conformation of N,N-bis-(phthalimidopropyl)-N-octylamine is folded and stabilized by an intramolecular CH⋯O hydrogen bond. A close similarity to the conformation of N,N-bis-(phthalimidopropyl)-N-propylamine has been found. The both molecules differ by the length of the saturated chains on the N-amine atom. The long N-octyl chain substituent gives rise to the supramolecular structure which is different to that one formed by the N-propyl derivative. The supramolecular structure is driven by weak CH⋯O and π⋯π interactions. The optimized bond lengths as well as bond angles for N,N-bis-(phthalimidopropyl)-N-octylamine calculated by B3LYP/6-31G(d,p) approach are compared with the X-ray data. The screening constants for 13C and 1H atoms have been calculated by the GIAO/B3LYP/6-31G(d,p) approach and analyzed. Linear correlations between the experimental 1H and 13C chemical shifts and the computed screening constants have been obtained.