Protonation and sequestering properties of diethylene triamino-penta-propionic acid with the actinide ions (Th⁴⁺, U⁴⁺, Pu⁴⁺), lanthanide ions (Pr³⁺, Nd³⁺, Eu³⁺, Gd³⁺, Er³⁺) and some divalent ions (Ca²⁺, Cu²⁺, Zn²⁺, Hg²⁺)

The object of this thesis is the study of a new complexing agent that have been synthesized and which results from an attempt to optimize properties of DTPA by chain lengthening; this study is limited to the chemical aspect of the behavior of diethylene triamino penta-propionic acid (DTPP). The first part is a general presentation of this complexing agent (reasons which guided its choice, synthesis and purification, complete study of protonation including the determination of acidity constants and the order of protonation sites. The second part presents its behavior with respect to the complexation of actinides and metals such as calcium and zinc; complexation constants are calculated and a chapter on lanthanides is included as radioimmunotherapy needs strong sequestering agents capable of complexing α and β^- emitting radionuclides for labeling monoclonal antibodies. The third part introduces the problems of degradation of the complexing as a function of time, in different protonated and complexed forms. As a conclusion, the properties of the studied ligand are shown and compared to those collected in the literature for other chelating agents.