3d-4f magnetic exchange interactions and anisotropy in a series of heterobimetallic vanadium()-lanthanide() Schiff base complexes

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 5; no. 39; pp. 13883 - 13893
• Main Authors: Kotrle, Kamil, Nemec, Ivan, Moncol, Jan, i már, Erik, Herchel, Radovan
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 12.10.2021
• Subjects: Anisotropy; Antiferromagnetism; Coordination numbers; Erbium; Exchanging; Ferromagnetism; Gadolinium; Imines; Magnetic properties; Magnets; Single crystals; X ray analysis
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d1dt01944a

A series of heterobimetallic Ln III -V IV compounds [Ln(VO)L(NO 3 ) 3 (H 2 O)] (Ln = Gd( 1 ), Tb( 2 ), Dy( 3 ), and Er( 4 )) assembled by a Schiff base ligand (H 2 L = N , N ′-bis(1-hydroxy-2-benzylidene-6-methoxy)-1,7-diamino-4-azaheptane) were prepared and studied with experimental and theoretical methods. The single-crystal X-ray analysis revealed the change of the coordination number from 10 found in 1-3 to 9 confirmed in 4 . The DC magnetic data were fit with several Hamiltonians to extract the exchange and anisotropy parameters of complexes 1-4 . This investigation of magnetic properties was carried out using both DFT and CASSCF theoretical calculations. It was found out that exchange interactions in 1 , 3 and 4 are antiferromagnetic, while 2 has ferromagnetic exchange interactions. Moreover, the AC susceptibility measurements revealed the field-induced slow relaxation of magnetization in complexes 2 and 3 which is complicated by the presence of three relaxation channels. Nevertheless, these compounds belong to the first Tb III -V IV and Dy III -V IV single-molecule magnets in this class of compounds. 3d-4f complexes were prepared and their X-ray analyses revealed changes in the coordination number upon changing the lanthanide (Gd → Er). The V IV -Ln III magnetic exchange was fit from magnetic data and calculated by DFT and CASSCF theoretical models.