Synthesis, structures, magnetic and optical properties of two lanthanide [Ln ¼ Sm(III), Dy(III)] complexes with chelating nitronyl nitroxide radicals

The synthesis, structures, magnetic and optical properties of two lanthanide complexes with chelating nitronyl nitronide radicals of formula [Ln(III)(NIT2Py)2(NO3)3·xH2O] (Ln ¼ Sm(III) 1, x ¼ 0; Dy(III) 2, x ¼ 0:25) (NIT2Py ¼ 2-(20-pyridyl)-4,4,5,5-tetramethylimidazoline- 1-oxyl-3-oxide) are reported. The lanthanide ion of each complex is 10-coordinated with three bidentate nitrate anions and two radicals (NIT2Py). The radical behaves as a bidentate chelating ligand through one nitroxide oxygen atom and one pyridine nitrogen atom. The absorption spectra of two complexes show that the covalency decreases as the atomic number of the rare earth metal atom increases. The magnetic susceptibilities for complexes were measured in the 77–300 K region at 10,000 G. q 2004 Elsevier B.V. All rights reserved