Complex formation in the 3-(2-thiazolylazo)-2,6-diaminopyridine-palladium(II) system

The complexation of 3-(2-thiazolylazo)-2,6-diaminopyridine (TADAP) with palladium was studied in 15 associated solvents with an ordered spatial structure and in 26 nonassociated and nonstructured aprotic solvents. The acid-base forms of TADAP involved in complexation were identified and shown to be different for the two groups of solvents. The optimal conditions of complexation were found. The molar absorption coefficients at the absorption maxima were determined. The stability constants for the palladium complexes with TADAP in various solvents were calculated. The dependence of the stability constants on the dielectric constant and polarizability of the solvent molecules was elucidated.