4f-4f absorption spectral study for the interaction of Pr(III) and Nd(III) with uracil in presence and absence of Ca(II): A Model on the use of Ln(III) as probes at Ca(II) binding sites in biological systems.

Abstract

A bioinorganic approach into the problem of the isomorphous substitution of calcium(II) by lanthanide(III) ions in biological system is explored through absorption difference and comparative absorption spectroscopy involving 4f-4f transitions. The interaction of Pr(III) and Nd(III) with uracil induced substantial changes in the intensities of 4f-4f bands and their perturbation was reflected through oscillator strength and Judd-Ofelt intensity (Tλ) parameters. Intensification of these bands became more prominent in presence of Ca(II) thereby suggesting that the changes in the oscillator strengths of different 4f-4f bands and Judd-Ofelt intensity (Tλ) parameters can be followed to predict in vivo intracellular complexation of uracil with Ca(II) in vitro as both Pr(III) and Nd(III) have unique similarity in their coordination with Ca(II).