Mixed ligand complexes of manganese with some L-amino acids and β-picoline -: A polarographic approach

Polarography was used to determine the stability constants (log beta) of ternary complexes of Mn(II) with glycine, alpha-alanine, L-valine, L-leucine, L-asparagine and L-glutamine as primary Iigands and beta- picoline as the secondary ligand at pH = 8.30 +/- 0.01 and ionic strength mu = 1 M NaClO4 at 298 K. The waves of Mn and its complexes were quasi-reversible. Mn(II) formed 1:1:1, 1:1:2 and 1:2:1 complexes. The trend of stability constants of Mn(II) complexes with respect to amino acids and beta-picoline is L-glutamine < L-asparagine < L-valine < L-leucine < or-alanine < glycine which is explained on the basis of sizes and basicities of these Iigands.