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

• Published in: Inorganica Chimica Acta 2015-05, Vol.430, p.1-7
• Main Authors: Song, Mei-Ying, Wen, Long-Mei, Wang, Shu-Ping, Yang, Shu-Tao, Zhang, Jian-Jun, Geng, Li-Na, Shi, Shi-Kao
• Format: Article
• Language: English
• Subjects: Crystal structure; Lanthanide complex; Magnetic property; Nitronyl nitroxide radical; Thermodynamics property
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2015.02.018

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. [Display omitted] •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=2.00cm−1, and antiferromagnetic interaction between radicals with JRad–Rad=−8.50cm−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).