Mixed-ligand lanthanide complexes—X. Interaction of trivalent lanthanides with 1,10-phenanthroline and thiocyanate in alcohol

Abstract

The interaction of trivalent lanthanide thiocyanates and phen in ethanol results in the formation of the complexes of the type [Ln(phen) 3(SCN) 3], where Ln = La, Pr, Nd, Sm and Eu; and [Ln(phen) 3 (SCN) 3(H 2O)], where Ln = Dy, Ho, Er and Yb. The complexes have been characterized by elemental analyses, molar conductance, IR spectra and thermal analyses. The complexes behave as non-electrolytes in methanol. TGA showed the presence of coordinated water in the case of the heavier lanthanides making them ten-coordinate. The NMR spectra of the complexes of La, Pr, Nd, Sm, Eu and Yb have been studied in DMSO- d 6 and pyridine- d 5. The complexes do not dissociate in DMSO and retain their coordination number. The chemical shift ratios are constant for different phen protons which indicates dipolar nature of the shift. Pyridine coordinates without displacing any ligand and increases the coordination number of the lighter lanthanides from nine to ten.