Multidentate aza ligands able to complex metal ions and the use thereof in diagnostic and therapy

Compounds of general formula (I):in which: R1 is hydrogen, C1-C2O alkyl, C3-C10 cycloalkyl, C4-C2O cycloalkylalkyl, aryl, arylalkyl, or two R1, taken together, form a straight or cyclic C2-C10 alkylene group or an ortho disubstituted arylene; R2 is hydrogen, C1-C2O alkyl, C3-C10 cycloalkyl, C4-C2O cycloalkylalkyl, aryl or aryl alkyl optionally substituted with functional groups which allow conjugation with a suitable molecule able to interact with physiological systems; R3, R4 and R5 are hydrogen, C1-C20 alkyl, C3-C10 cycloalkyl, C4-C2O cycloalkylalkyl, aryl, arylalkyl; and their chelates with bi-trivalent ions of the metal elements having atomic number ranging between 20 and 31, 39, 42,43,44,49, and between 57 and 83, and radioisotopes chosen among <203>Pb <67>Ga <68>Ga <72>As In <113>In <90>Y <97>Ru <62>Cu <64>Cu <52>Fe <52m>Mn , <140>La <175>Yb <153>Sm <166>Ho <149>Pm <177>Lu <142>Pr <159>Gd <2l2>Bi <47>Sc <149>Pm <67>Cu, <111> Ag, <199> Au, <161>Tb and <51>Cr as well as the salts thereof with physiologically compatible bases or acids.