In the present research work, the absorption difference and comparative absorption spectroscopic studies involving 4ƒ-4ƒ transitions of Pr(III) with acetyl acetone [Pr(acac)3(H2O)2] and their adducts with structurally related ligands viz., aniline (an), bromoaniline (Bran) and chloroaniline (Clan) complexes in different solvents like methanol (CH3OH), acetonitrile (CH3CN) and dimethyl formamide (DMF) have been carried out. The intra 4ƒ-4ƒ transition spectra yield sharp bands which were analyzed individually by Gaussian curve analysis, the energy interaction parameters (FK,EK), Lande spin orbit coupling (ξ4f), nephelauxetic ratio (β), bonding parameter (b1/2), percent covalency (δ) were calculated and intensity parameters have been computed on computer using partial multiple regression analysis. The obtained results are used to determine the probable geometry of complexes in solution and nature of the bond between Pr (III) ion and ligands, the inner sphere coordination of 4ƒ-4ƒ transition.
