Complexation of praseodymium and calcium cations with N-benzoylglutamic acid

The dissociation of N-benzoylglutamic acid (H(2)Bzglu) and the formation of complexes of Pr3+ and Ca2+ with H(2)Bzglu were studied by potentiometric t itration (with glass and Ca-selective electrodes) at 25 degrees C and a ion ic strength of 0.1 (KCl). The results obtained were processed within the fr amework of a mathematical model. The values of pK(dis) for H(2)Bzglu were f ound to be pK(1) = 3.91 + 0.09 and pK(2) = 5.23 +/- 0.06. The most importan t complexes of praseodymium and calcium with H2L (L = Bzglu(2-)) were ident ified: PrL+, PrHL2+ PrH2L3+, PrOHL, Pr2L4+, Pr-2(OH)L3+, Pr2HL5+, PrL2-, Ca (OH)L-, and Ca-2(OH)L+. The complexation constants were calculated.