From Dy-chain to Dy-dimer: Significant structural variation induced only by counter cations and slow magnetic relaxation behaviors

• Published in: Journal of molecular structure Vol. 1316; p. 139038
• Main Authors: Liu, Ying, Guo, Ke-Ke, Wu, Jin-Long, Tang, Shen, Teng, Qing-Hu, Liang, Fu-Pei, Wang, Kai
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2024
• Subjects: Counter cation; Dy complex; Single molecule magnet; Slow magnetic relaxation; Structural variation; Single molecule magnet; Dy complex; Slow magnetic relaxation; Counter cation; Structural variation
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2024.139038

•Only by the changing of the counter cations with different steric hindrances, we have modified the molecular structures a family of Dy complexes successfully, achieving a significant variation form chain topologies to the dimer structure.•It is the first realization in lanthanide complex family for such dramatic structural variation (from infinite chain to discrete dimer) induced only by counter cations.•The complexes show different field-induced single molecule magnet behavior. Herein we report a family of Dy complexes with 1,1,1,5,5,5-hexafluoropentane-2,4‑dione (Hhfac), [Et2MeNH][Dy(hfac)3(OAc)] (1), [Et3NH][Dy(hfac)3(OAc)] (2) and [(n-Pr)3NH]2[Dy2(hfac)6(OAc)2] (3), among which a rare structural variation has been realized by the change of organic ammonium counter cations. These complexes are all constructed from mononuclear [Dy(hfac)3] building units and OAc− linkages, while employing different protonated tertiary amines as the counter cations. The Namine-H∙∙∙Oacetate hydrogen bonds, which are formed between counter cations and OAc− bridges in all complexes, make each counter cations just wedge into the gaps between adjacent [Dy(hfac)3] building units. The hfac‒ groups of each [Dy(hfac)3] unit thus inversed to other side along with the enlarging of the steric hindrance of counter cations, resulting in a significant structural variation from infinite chain topologies of 1 and 2 to discrete dimer structure of 3. For such significant structural variation induced only by the counter cations, to our knowledge, it is the first time in the whole lanthanide complex family. The magnetic studies revealed that 1–3 all show field-induced single-molecule magnets (SMMs) behavior, with the efficient energy barriers (Ueff) of 23.9, 8.5, and 11.2 K, respectively. Synopsis: Only by changing the counter cations with different steric hindrances, we have modified the molecular structures of a family of Dy complexes with SMM behavior successfully, realizing a significant variation form chain topologies to the dimer structure. [Display omitted]