Pyridinaldazines as Analytical Reagents

The synthesis, characteristics and analytical applications of the three pyridylazines are described. The ortho isomer reacts with Fe(II) to produce a bidentate 1:3 red complex (λmax = 475 nm), which undergoes a rearrangement by a “in situ” reaction into tridentate 1:2 blue complex (λmax, = 660 nm, ∊ = 2.9.103 1.mol−1.cm−1). The optimal conditions for max formation of the blue complex are determined. A spectrophotometric method for the determination of iron is also proposed. The interferences of tile foreign ions arc determined.