Two Tri-spin Complexes Based on Lanthanide (LnⅢ =DyⅢ and TbⅢ) and Nitronyl Nitroxide Radicals: Syntheses, Structures and Properties

摘要

Two new tri-spin radical-Ln(Ⅲ)-radical complexes, [Ln(hfac)3(NITPh-Ph)2] (Ln=Dy(1) and Tb(2), NITPh-Ph=4 '-biphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, and hfac=hexafluoroacetylacetonate) have been synthesized and characterized by X-ray diffraction analysis, elemental analysis, IR, Uv-visible and magnetic properties. X-ray analysis reveals that the two complexes are isomorphous and crystallize in the triclinic system, space group Pī. For complex 1, a=12.402(3), b=15.414(3), c=17.383(3), α=68.61(3), β=81.97(3), γ=79.40(3)°, V=3031.7(11)3, Z=2, Mr=1401.86, Dc=1.536 g/cm3 , μ=1.344 mm-1 , F(000)=1398, the final GOF=1.173, R=0.0670 and wR=0.1376 for 9035 observed reflections with I>2σ(I); while for complex 2, a=12.397(3), b=15.391(3), c=17.395(4) , α=68.62(3), β=81.97(3), γ=79.60(3)°, V=3030.0(11)3 , Z=2, Mr=1398.29, Dc=1.537g/cm3, μ=1.344 mm-1 , F(000)=1398, the final GOF=1.130, R=0.0644 and wR=0.1382 for 8989 observed reflections with I>2σ(I). They all consist of the discrete adducts, in which the central Ln(Ⅲ) ions are coordinated by six oxygen atoms from three hfacs and two oxygen atoms from nitronyl radicals. The temperature dependency of magnetic susceptibilities for these two complexes is studied, showing that the magnetic interactions are governed by the depopulation of the Ln Stark levels.