| Abstract |
In this work, the absorption and the fluorescence emission properties as well as the protonation sequence of three open chain polyamine Ligands of different dimensions bearing an anthracene unit were studied. The protonation and stability constants with Ni2+, CU2+, Zn2+, and Cd2+ have been determined in 0.15 mol . dm(-3) NaCl at 298.1 +/- 0.1 K. The values of both protonation and stability constants follow the expected trends according to the number of nitrogen donors, sequence of chelate rings and hydrophilic-hydrophobic balance. Chechelation enhancement of the fluorescence emission (CHEF) was observed for some complexes of these Ligands with Zn2+ and Cd2+. In contrast the analog complexes containing Cu2+ and Ni2+ exhibit a chelation enhancement of the quenching (CHEQ) except for the complexes with the largest chain where some protonated metal complexes are emissive. These systems are explored from the point of view of chemosensors for logic operations at the molecular level. |
