Phthalocyanine supported dinuclear LnIII complexes: the solvent-induced change of magnetic properties in dysprosium(iii) analogues

Abstract

Three dinuclear lanthanide complexes, [Ln₂(thd)₄Pc]·2C₆H₆ (Hthd = 2,2,6,6-tetramethylheptanedione, Ln = Sm (1), Tb (2), Dy (3)), have been synthesized based on phthalocyanine (Pc). They can be reversibly transformed into [Ln₂(thd)₄Pc] (Ln = Sm (1′), Tb (2′), Dy (3′)) via desolvation and resolvation of the lattice benzene molecules. This change generates dramatic influences on the structural and magnetic properties of the dysprosium analogue. In complex 3, one crystallographically independent metal center is observed, and it exhibits a single relaxation process of magnetization with an energy barrier of 55.7 K. Upon desolvation, the resulting complex 3′ contains two types of metal centers, and shows the field-induced single-molecule magnetic behavior with two thermally activated magnetic relaxation processes. The anisotropy barriers for 3′ are as high as 63.3 K and 109.6 K, respectively. This work confirms that the solvated molecules can finely tune the magnetic relaxation mechanisms.