Molecular Dioxygen Binding to Co(II) Complexes with Open-Chain and Macrocyclic Polyaazalkanes in Aqueous Solutions

The reaction of dioxygen binding on Co(II) complexes with the polynucleating Ligands 1,23-bis(methylamino)-3,6,9, 12,15,18,21 -heptaazatricosane, (Me(2)octaen), 1,4,7,10,13,16,19,22,25-nonaazacycloheptacosane ([27]aneN(9)), 1,4,7, 10,13,16,19,22,25,28-decaazacyclotriacontane ([30]aneN(10)), and 1,4,7,10,13,16,19, 22,25,28,31-undecaazacyclotritriacontane ([33]aneN(11)), in aqueous solution is here considered. By changing the values of the ligand to cobalt concentrations ratio, R, and of the pH of the solution, the formation of three types of dioxygen adducts is recognized and their evolution with time analyzed