Thermodynamic studies on complexation of divalent transition metal ions with some zwitterionic buffers for biochemical and physiological research

摘要

The interaction between the zwitterionic buffers(3-[N-bis(2-hydroxyethyl)amino]-2-hydroxy propane sulfonic acid,N-(2-actamido)-2-aminoethane sulfonic acid,and 3-[(1,1-dimethyl-2-hydroxyethyl)amino]-2-hydroxy propane sulfonic acid)with some divalent transition metal ions(Cu~(II),Ni~(II),Co~(II),Zn~(II),and Mn~(II))were studied at different temperatures(298.15 to 328.15)K at ionic strength I= 0.1 mol o dm~(-3)NaNO3 and in the presence of 10%,30%,and 50%>(w/w)dioxene by using potentiometry.The thermodynamic stability constants were calculated as well as the free energy change for the 1:1 binary complexation.The protonation constants of the zwitterionic buffers were also determined potentiometrically under the above conditions.