Polyamine complexes with seven-membered chelate rings: complex formation of 3-azaheptane-1,7-diamine, 4-azaoctane-1,8-diamine (spermidine), and 4,9-diazadodecane-1,12-diamine (spermine) with copper(II) and hydrogen ions in aqueous solution
Equilibrium constants have been determined for protonation of the linear triamines 3-azaheptane-1,7-diamine (3NH-hd) and 4-azaoctane-1,8-diamine (4NH-od, spermidine) at l= 0·10M(NaCl) and 25 °C. Enthalpy (calorimetric) and entropy data are reported for protonation of 4,9-diazadodecane-1,12-diamine (4,9NH-ddd, spermine). Equilibrium formation constants and spectrophotometric data are also given for the complexes [CuL]2+, [Cu(HL)]3+, [Cu(OH)L]+(L = 3NH-hd or 4NH-od), and [Cu(HL)2]4+(L = 3NH-hd). The data are compared & with those for analogous tri- and tetra-amines.