Yttrium and Lanthanide Nitrate Complexes of 4-Formyl-2, 3-Dimethyl-1-Phenyl-3-Pyrazolin-5-One

Abstract

Complexes of yttrium and lanthanide nitrates with 4-formyl-2, 3-dimethyl-1-phenyl-3-pyrazolin-5-one (FDPP) having the general formula [Ln(FDPP)₂(NO₃)2]NO₃, where Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho and Er have been synthesised and characterised by elemental analyses, molar conductance in non-aqueous solvents, electronic, infrared and proton NMR spectra as well as thermogravimetric analyses. FDPP acts as a neutral monodentate ligand, coordinating through the ring carbonyl oxygen and two of the nitrate ions are coordinated in a bidentate manner. A. coordination number of six may be assigned to the metal ion in these complexes. The covalency parameters evaluated from the solid state electronic spectra suggest weak covalent character of the metal-ligand bond. The TG data of the lanthanide complexes indicate that the complexes are stable up to about 170°C. and undergo decomposition in two stages forming the respective anhydrous lanthanide oxide as the final product.