Syntheses, structures, magnetic and thermodynamics properties of tri-spin lanthanide complexes of nitronyl nitroxide

• Three novel tri-spin Ln(III)-radical complexes have been synthesized.
• Their magnetic properties are studied.
• Their thermodynamics properties are studied.

Three new nitronyl nitroxide radical-Ln(III) complexes, Ln(hfac)3(NITPhOCF3)2 (Ln(III) = Gd(1), Tb(2), Dy(3); NITPhOCF3 = 2-(4-trifluoromethoxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; hfac = hexafluoroacetylacetonate), have been synthesized and characterized. They are isostructural, which show mononuclear tri-spin structures. The central Ln(III) ion is eight-coordinated by three hfac anions and two NITPhOCF3 molecules. Direct-current magnetic studies show that there exist ferromagnetic interactions between Gd(III) ion and radicals (NITPhOCF3) with JGd–Rad = 2.00 cm−1, and antiferromagnetic interaction between radicals with JRad–Rad = −8.50 cm−1 in complex 1. Meanwhile antiferromagnetic interactions are estimated between Ln(III) (Ln(III) = Tb(III), Dy(III)) and radicals in complex 2 and 3, respectively. The thermodynamics properties of three complexes were studied with differential scanning calorimetry (DSC), such as heat capacity, thermodynamic functions (HT − H298.15K), (ST − S298.15K), and (GT − G298.15K).

Using a novel nitronyl-nitroxide radical (NITPhOCF3), we obtained and characterized three isostructural lanthanide mononuclear tri-spin compounds. The magnetic properties and thermodynamics properties were studied.Figure optionsDownload as PowerPoint slide