Molecular dioxygen binding to Co(II) complexes with open-chain and macrocyclic polyazaalkanes in aqueous solutions

The reaction of dioxygen binding on Co(II) complexes with the polynucleatin g 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 t o cobalt concentrations ratio, R, and of the pH of the solution, the format ion of three types of dioxygen adducts is recognized and their evolution wi th time analyzed.