Multifunctional properties of {CuLn} systems involving nitrogen-rich nitronyl nitroxide: single-molecule magnet behavior, luminescence, magnetocaloric effects and heat capacity

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 5; no. 8; pp. 2854 - 2863
• Main Authors: Li, Hongdao, Jing, Pei, Lu, Jiao, Xi, Lu, Wang, Qi, Ding, Lifeng, Wang, Wen-Min, Song, Zhenjun
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 02.03.2021
• Subjects: Chloroform; Clusters; Crystallography; Dysprosium; Fluorescence; Gadolinium; Imidazoline; Investigations; Luminescence; Magnetic properties; Maximum entropy; Multifunctional materials; Optical properties; Pyrazole; Specific heat; Spin glasses; Thermodynamic properties
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d0dt04344c

A series of nitrogen-rich nitronyl nitroxide radical PPNIT ( 1 )-based (PPNIT = 2-(1-(pyrazin-2-yl)-1 H -pyrazole)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide) 3d-4f ring-shaped tetranuclear clusters [Ln 2 Cu 2 (hfac) 10 (PPNIT) 2 (H 2 O) 2 ]·CHCl 3 (Ln III = Gd 2 , Tb 3 , Dy 4 ; hfac = hexafiuoroacetylacetonate) with multifunctional properties were isolated. The magnetic behavior, luminescence and heat capacity of the 3d-4f complexes were investigated, displaying interesting multiple properties of the molecular materials. The Gd derivative shows a magnetocaloric effect with the maximum entropy change (−Δ S m ) of 15.3 J kg −1 K −1 at 2 K for Δ H = 70 kOe. The Tb cluster exhibits spin glass behavior and the characteristic fluorescence emission of the Tb III ion, while the Dy cluster exhibits SMM behaviour, and the heat capacity has been investigated. Notably, in nitronyl nitroxide radical-metal systems, the investigation of diverse properties is still scarce so far. This work can pave the way towards the synthesis of multifunctional materials that combine SMM behavior, and optical or/and thermodynamic properties. A family of 3d-4f heterometallic ring-shaped clusters on the basis of a nitrogen-rich nitronyl nitroxide radical have been obtained, and they feature polyfunctionality including magnetic properties, thermodynamics and luminescence behavior.