1,5-Diaminopentanetriols and 1,6-diaminohexanetetrols, potent dimer-forming ligands for Cu2+ ions. Potentiometric and spectroscopic studies

A series of diaminoalcohols (1,5-diaminotriols and 1,6-diaminotetrols) have been synthesised and their co-ordination abilities towards CuII studied by potentiometry and spectroscopic techniques (UV/VIS, EPR and CD). Both amino groups act as anchoring sites for two metal ions. Thus, two independent NH2, O– chelates are formed leading to dimeric complexes in which two metal ions are bound to two N-terminal atoms of the 1,5- or 1,6-diaminoalcohols. In all cases studied both ligand conformation and absolute configuration have a distinct impact on the stabilities of the complexes formed.