3,3,3-Trifluoro-N'-(3-trifluoromethylphenyl)-l,2-propanediamine and its N-mono-and N,N-dicarboxyethyl derivatives: synthesis,protolytic and complexation properties

摘要

3,3,3-Trifluoro-N'-(3-trifluoromethylphenyl)-l,2-propanediamine (5) was synthesized by the reaction of 2-diazo-1,1,1 -trifluoro-3-nitropropane or 3,3,3-trifluoro-l-nitropropene with 3-aminobenzotrifluoride followed by the reduction of the nitro group.The Michael 1,4-addition of diamine 5 to acrylic acid occurs only at the N(1) atom and affords N-mono-or N,N-dicarboxyethyl derivatives 6 and 7,depending on the reactant ratio.Protolytic equilibria 5-7 in aqueous solutions were studied by pH-potentiometry and UV spectroscopy.Only the aliphatic amino group can be protonated in an aqueous solution,while the aromatic amino group remains unprotonated even in 12 M HC1.The stability constants of transition metal (Cu~(2+),Ni~(2+),Zn~(2+)) complexes with ligands 5-7 were determined by pH-potentiometric titra-tion.The stability of the complexes and selectivity of the ligands toward Cu2+ ions increase with an increase in the number of N-carboxyethyl groups.