Syntheses, structures and magnetic properties of novel tetrameric Ln2Mn2 and ring-like Ln4Mn4 clusters. (3rd June 2020)

• Record Type: Journal Article
• Authors: Yin, Jia-Jia; Chen, Cheng; Zhuang, Gui-Lin; Zheng, Jun; Zheng, Xiu-Ying; Shao, Feng
• Is Part Of: New journal of chemistry. Volume 44:Number 23(2020)
• Page Start: 9837
• Page End: 9843
• Publication Date: 2020-06-03
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d0nj01517b
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Two series of heterometallic Ln–Mn clusters Ln2 Mn2 and Ln4 Mn4 were successfully synthesized in the presence of alcohol ligands, and the magnetic coupling interaction between metal ions were characterized by theoretical calculations. Abstract : Three tetrameric Ln–Mn clusters with formulae [Ln2 Mn2 (hmp)6 (NO3 )4 (H2 O)4 ](ClO4 )2 · x H2 O (Ln = Y, x = 1 (1 ); Ln = Gd, x = 3 (2 ); Ln = Dy, x = 4 (3 )) and three ring-like Ln–Mn clusters [Ln4 Mn4 (hmp)4 (L)4 (H2 L)4 (CH3 CN)(H2 O)7 ](NO3 )4 ·H2 O (Ln = Y (4 ), Gd (5 ), Dy (6 ), hmpH = 2-(hydroxymethyl)pyridine, H3 L = 2, 2-bis(hydroxymethyl)butyric acid) have been synthesized in the presence of alcohol ligands. Single X-ray analysis revealed that compounds 1 –3 exhibited a zigzag metal core unit of [Y2 Mn2 (hmp)6 ] 6+ ([Y–Mn–Mn–Y]), which could form a three-dimensional (3D) metal framework via π–π stacking. Compounds 4 –6 formed the ring-shaped metal skeleton of Ln4 Mn4 and displayed an ideal metal arrangement with alternating Ln and Mn ions, which was consistent with the predicted metal arrangement of [–Ln–M–Ln–M–] with weak magnetic interactions. Investigation into the magnetic properties showed that 1 displayed significant ferromagnetic interactions and 2 –6 displayed dominant antiferromagnetic interactions. Magnetic calculations showed that in 2, Gd⋯Mn and Mn⋯Mn presented an antiferromagnetic interaction and a weak ferromagnetic interaction, respectively. For 5, Gd⋯Mn showed a weak antiferromagnetic interaction and Gd⋯Gd showed a much weaker ferromagnetic interaction due to the spacing of Gd(iii ) ions by Mn(iii ) ions, which effectively weakened the antiferromagnetic coupling between Gd 3+ ions. In addition, magnetothermal studies showed that 5 displayed magnetic entropy changes of 15.5 J kg −1 K −1 at 3.5 K for Δ H = 7 T.