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The present paper covers the synthesis and the characterization of ligand 2-decyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid,H_5L,and its Gd(Ⅲ) chelate. The protonation constants for H_5L(lg K H_ i =10.90,8.50,4.55,2.92,2.20) and the stability constant for GdL 2- (lg K _ GdL 2- =22.80) were determined by means of potentiometric titration. They are similar to the corresponding values of DTPA and Gd-DTPA,respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after the introduction of a linear chain decyl group into the terminal acetic acid residue of DTPA. The Gd(Ⅲ) chelate may be a potential contrast agent with liver-specificity for magnetic resonance imaging(MRI).
The present paper covers the synthesis and the characterization of ligand 2-decyl-3,6,9-tris (carboxymethyl) -3,6,9- triazaundecan-1,11-dioic acid, H_5L, and its Gd (III) chelate . The protonation constants for H_5L (lg KH_i = 10.90,8.50,4.55,2.92,2.20) and the stability constant for GdL 2- (lg K_GdL2 = 22.80) were determined by means of potentiometric titration. They are similar to the corresponding values of DTPA and Gd-DTPA, respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd (III) chelate are not visible altered after the introduction of a linear chain decyl group into the The acetic acid residue of DTPA. The Gd (Ⅲ) chelate may be a potential contrast agent with liver-specificity for magnetic resonance imaging (MRI).