Energetics of lead(II), cadmium(II) and zinc(II) complexes with amino acids

Abstract

The molar heat capacity and the standard (p(0) = 0.1 MPa) molar enthalpies of formation of the crystalline of bis(glycinate) lead(II), Pb(gly)(2); bis(DL-alaninate) lead(II), Pb(DL-ala)(2); bis(DL-valinate) lead(II), Pb(DL-val)(2); bis(DL-valinate) cadmium(II), Cd(DL-val)(2) and bis(DL-valinate) zinc(II), Zn(DL-val)(2), were determined, at T = 298.15 K, by differential scanning calorimetry, and high precision solution-reaction calorimetry, respectively. The standard molar enthalpies of formation of the complexes in the gaseous state, the mean molar metal-ligand dissociation enthalpies, M(II)-amino acid, < D(m)>(M-L), were derived and compared with analogous copper(II)-ligand and nickel(II)-ligand. [GRAPHICS] .