Complex formation with a C-alkyl-substituted linear tetra-amine. Free energy, enthalpy, and entropy changes for the reactions of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-diamine with copper(II) ions and protons in aqueous solution

Thermodynamic data are reported for the protonation of the hexamethyl-substituted tetra-amine 4,4,9,9-tetra-methyl-5,8-diazadodecane-2,11-diamine (hm-3,2,3-tet) and for the formation of the copper complex Cu(hm-3,2,3-tet)2+. Data are compared with those for the unsubstituted tetra-amine, 3,2,3-tet; small differences in stepwise protonation constants and in copper complex stabilities relate mainly to differences in ΔS values.