摘要
The binary systems of RE3+ with the newly synthesized fluorescent reagent H2L[5(2'-carboxybenzenazo) rhodanine] (RACP), 5-(4'-chloro-2'-carboxybenzenazo) rhodanine (Cl- RACP) and 5-(4'-bromo-2'-carboxybenzenazo) rhodanine (Br-RACP) in 70% ethanol aqueous solutions have been studied by potentiometric titration. The formation constants and distribution of various species al different pH have been determined. The apparent dissociation constants of H2L decrease on the following sequence:RACP>Cl-RACP>Br-RACP, but the cumulative formation constants of the complexes with Nd3+ remain constant. Further investigation on the binary systems of 15 RE elements with RACP. 1gβ110 and 1gβ120 values shows 'tetrad effect', and no complex in the form of ML3 exists in the systems.
The binary systems of RE3+ with the newly synthesized fluorescent reagent H2L[5(2'-carboxybenzenazo) rhodanine] (RACP), 5-(4'-chloro-2'-carboxybenzenazo) rhodanine (Cl- RACP) and 5-(4'-bromo-2'-carboxybenzenazo) rhodanine (Br-RACP) in 70% ethanol aqueous solutions have been studied by potentiometric titration. The formation constants and distribution of various species al different pH have been determined. The apparent dissociation constants of H2L decrease on the following sequence:RACP>Cl-RACP>Br-RACP, but the cumulative formation constants of the complexes with Nd3+ remain constant. Further investigation on the binary systems of 15 RE elements with RACP. 1gβ110 and 1gβ120 values shows 'tetrad effect', and no complex in the form of ML3 exists in the systems.
