Spectrophotometric determination of the $pK_a$ values of some aminoacid complexes of pentacyanoferrate (II) and pentacyanoruthenate (II)

Abstract

The syntheses, $pK_a$ and spectrospcopic characterization of $[Fe(CN)_5(H_2O)]^{-3}$ and $[Ru(CN)_5(H_2O)]^{-3}$ complexes of alanine(Ala), glycine(Gly), valine(Val), lysine(Lys), arginine(Arg) and cysteine(Cys) complexes were investigated in aqueous solution. The spectra of the complexes containing amino acid ligands were similar to that of $[Fe(CN)_5(H_2O)]^{-3}$. The $pK_a$ values of the complexes were measured by spectrophotometric titration at $22^circ C$ and $mu =0.100 M(NaClO_4)$.