摘要
We synthesised a series of ω-aminoalkyl sodium hydrogen phosphates （AAP-n-Na, n =3, 4, 5, 6, purity 〉 99%）, which have potential applications as bioactive cosmetic ingredients and surface modifiers of bone minerals （i.e. hydroxyapatites）. Results from Fourier transformed infrared （FTIR）, nuclear magnetic resonance （NMR） and high resolution mass spectroscopy, and elemental analysis all matched their chemical structures. The acid dissociation constants （pKa＇s） of each AAP-n （acid form of AAP-n-Na, n ; 2-6） were measured by potentiometric titration, showing a general increasing trend with an increase in the chain length of AAP-n. However, the pKa3 constant, which corresponds to the deprotonation of the ammonium group in AAP-n-Na, displayed an unusual decrease when n = even. This odd-even effect can be explained by the pairwise self-association of AAP-n-Na molecules in water where intermolecular hydrogen bonding in case of n=even is weaker than that in case of n=odd. All AAP-n-Na at concentrations up to 0.1% （w/v） were non-toxic to L929 fibroblasts and MG 63 osteoblast-like cells in terms of cell growth and morphology, These basic data were important for applications of AAP-n and their salts in biomedical engineering.
We synthesised a series of ω-aminoalkyl sodium hydrogen phosphates （AAP-n-Na, n =3, 4, 5, 6, purity 〉 99%）, which have potential applications as bioactive cosmetic ingredients and surface modifiers of bone minerals （i.e. hydroxyapatites）. Results from Fourier transformed infrared （FTIR）, nuclear magnetic resonance （NMR） and high resolution mass spectroscopy, and elemental analysis all matched their chemical structures. The acid dissociation constants （pKa＇s） of each AAP-n （acid form of AAP-n-Na, n ; 2-6） were measured by potentiometric titration, showing a general increasing trend with an increase in the chain length of AAP-n. However, the pKa3 constant, which corresponds to the deprotonation of the ammonium group in AAP-n-Na, displayed an unusual decrease when n = even. This odd-even effect can be explained by the pairwise self-association of AAP-n-Na molecules in water where intermolecular hydrogen bonding in case of n=even is weaker than that in case of n=odd. All AAP-n-Na at concentrations up to 0.1% （w/v） were non-toxic to L929 fibroblasts and MG 63 osteoblast-like cells in terms of cell growth and morphology, These basic data were important for applications of AAP-n and their salts in biomedical engineering.
基金
financial support from the National Natural Science Foundation of China (No. 50973069)
