Preparation and spectral studies for some chelate complexes of praseodymium

Abstract EN

Chelating complexes between praseodymium metal and each of (I) : Salicylaldehyde, (II) : β-diketone, Dibenzoyl methane (Ph – C(=O)- CH2 - C(=O)- ph) (DBM) and (III) : Schiff base of the type (ph – C(=O)-CH2 -C(=N-ph)-ph)) have been prepared.

The ligands and complexes were identified by their melting points and IR spectra in which complexes showed high melting points exceeded those for the original ligands, and clear differences in the IR spectra especially in the region of bending vibrations at 400 – 800 cm-1.

The fluorescence spectra for the ligands and their complexes with praseodymium have been studied in acidic and basic methanol solutions.

The influence of pH upon their fluorescence properties was also investigated.

For ligand II (DBM) the fluorescence intensity increases as acidity increase gradually, while it does not show any fluorescence emission in basic medium.

For the complex DBM- Pr3+, fluorescence intensity increases as the acidity gradually increase similar to that for 1x10 -3 M ligand DBM but to a larger amount for the complex.

It is concluded that in acidic medium the fluorescence spectra for all ligands and their complexes to praseodymium are increased with acidity but to a large extent for complexes compared with ligands.

In neutral medium, the change is negligible while in basic medium the fluorescence spectra are disappeared for each of ligands and their complexes with praseodymium.