In our group, triazole and sulfonamide ligands are designed and synthesized, and coordination compounds with various metal ions of biological interest [Cu(II), Zn(II), Fe(II,III),...] are subsequently prepared. These compounds are characterized structurally and spectrospically. In a second stage, the interaction of the resulting complexes with DNA is studied, and their nuclease activity is tested with and without activating agents. A novel approach is currently being explored: the activity of the synthesized metallonucleases is studied in combination with quantum dots (QDs) to enhance and/or activate their nucleolytic properties. The effect of photoactivation (with inert light) on the compounds and on the nuclease-QD systems is also investigated. Finally, the most active systems are tested in vivo on tumor cell lines. In parallel, the magnetic properties of the resulting polynuclear compounds are studied. In the case of cyclic trinuclear compounds, examples of spin frustration systems, a more exhaustive study of antisymmetric exchange is carried out.