Cu(II)-L-glutamine and L-asparagine binary complexes. A thermodynamic and spectroscopic study

The binary complexes of H+ and Cu(II) with L-glutamine and L-asparagine were studied by a combined potentiometric and calorimetric investigation. The thermodynamic parameters while on one hand help in understanding the role played by the chain length on the basicity of the amino group, on the other hand do not give a clear-cut answer as to the involvement in the coordination to Cu(II) of the terminal amido group of L-asparagine. The spectroscopic investigation (EPR and UV-VIS) carried out to solve this problem, clearly shows that both ligands are bidentate.