Synthesis and spectro-kinetic study of the complexes of Pd+2 Ion with 2-(5-Bromo-2-pyridylazo)‎-5diethylaminophenol reagent in ethanol-water solutions

Abstract EN

The complexes of Pd+2 ion with 2-(5-bromo-2-pyridylazo)-5-dieihyl aminophenol (BPADAP) were studied kinetically and spectrophotometrically in aqueous ethanolic solutions.

Tile reagent forms 1:1.

2:1 square planer and 1:1 bridged shape binuclear complexes with Pd+2ion.

All these complexes (violet colour) absorb light in the same region at 540, 575 and 618nm.

The band at 618 nm seems to be specific for complexes of Pd+2 ion with BPADAP.

The rate constants of the growth m 93% H:0 + 7% ethanol of 1:1 and 2:1 complexes at 575 and 618 nm were followed the first order kinetics and are quite of the same values .

0.495 and 0.463 min-1 respectively.

The rate constants of the decay of 2:1 complex at 618 and 575 nm were followed the first order kinetics; their values are 0.075 and 0.065 mm-1 respectively which are slower than the rate of the decay of 1:1 complex.

Whereas, the rate constants of the growth and decay of 1:1 bridged binuclear complex also followed the first order kinetics but they are much slower than those of 1:1 and 2:1 complexes: the values of the growth are 025 min-1at 575 nm .

and 0.16 mm-1 at 618 nm.

And the values of the decay are 0.0476 min-1 at 575 nm and 0.008 mm-1 at 61 8 nm.

It was found that BPADAP can identify and detect in ethanol at 575 and 618 nm less than one microgram up to more than seven micrograms of Pd+2 ion .

The interference of U02+2, TH+4.

Pb+2, Cd+2\Bi+3.

Hg+3 and Zn+2 in the detection of Pd+2 ion at 575 nm ranges between (25.3 - 67)%.

Whereas, the interference of these ions with the detection at 618 nm is only between (2.3 -3.9) %, so it is reasonable to suggest that BPADAP is a specific reagent for Pd+2 ion at 618 nm.