The reactions of LnIII ions with a versatile pyridyl-decorated dicarboxylic acid ligand lead to the formation of a series of novel three-dimensional (3D) Ln-MOFs, [Ln3(pta)4(Hpta)(H2O)]·xH2O (Ln = Dy (1), Eu (2), Gd (3), Tb (4), H2pta = 2-(4-pyridyl)-terephthalic acid, x = 6 for 1, 2.5 for 2, 1.5 for 3 and 2 for 4). The Ln3+ ions act as nine-coordinated muffin spheres, linking to each other to generate trinuclear {Ln3(OOC)6N2} SBUs, which are further extended to be interesting 3D topological architectures. To the best of our knowledge, the Dy-MOF exhibits zero-field single-molecule magnet (SMM) behaviour with the largest effective energy barrier among the previously reported 3D MOF-based Dy-SMMs. The combined analyses of a diluted sample (1@Y) and ab initio calculations demonstrate that the thermally assisted slow relaxation is mainly attributed to the single-ion magnetism. Furthermore, fluorescence measurements reveal that H2pta can sensitize EuIII and TbIII characteristic luminescence.
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http://dx.doi.org/10.1039/d0dt02736g | DOI Listing |
J Am Chem Soc
January 2025
Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
The integration of spin crossover (SCO) magnetic switching and electric polarization properties can engender intriguing correlated magnetic and electric phenomena. However, achieving substantial SCO-induced polarization change through rational molecular design remains a formidable challenge. Herein, we present a polar Fe(II) compound that exhibits substantial polarization change in response to a thermally regulated low-spin ↔ high-spin transition.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China.
Aromaticity is one of the most classical concepts in the field of modern chemistry and has been employed to explain and design substances with special stability. Although the knowledge about Hückel's and Baird's rules has been well established, the understanding of Möbius aromaticity remains extremely limited. In this letter, by employing density functional theory (DFT) calculations, we demonstrated that the four-membered VIB transition metal (TM) carbide clusters possess a highly stable open-shell planar tetrameric structure and exhibit double Möbius aromaticity, which was evidenced by analyzing multiple aromaticity criteria, including the electronic, magnetic, and energetic indicators.
View Article and Find Full Text PDFInorg Chem
January 2025
School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
Air-stable single-molecule magnets (SMMs) can be obtained by confining Dy ion in a coordination environment; however, most of the current efforts were focused on modifying the rigidity of the macrocycle ligand. Herein, we attempt to assemble air-stable SMMs based on macrocycles with a replaceable coordination site. By using an in situ 1 + 1 Schiff-base reaction of dialdehyde with diamine, three air-stable SMMs have been obtained in which one of the equatorial coordination sites can be varied from -NH- (for ), -O- (for ), and -NMe- (for ).
View Article and Find Full Text PDFJ Phys Chem A
January 2025
School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
Searching for single-molecule magnets (SMM) with large effective blocking barriers, long relaxation times, and high magnetic blocking temperatures is vitally important not only for the fundamental research of magnetism at the molecular level but also for the realization of new-generation magnetic memory unit. Actinides (An) atoms possess extremely strong spin-orbit coupling (SOC) due to their 5 orbitals, and their ground multiplets are largely split into several sublevels because of the strong interplay between the SOC of An atoms and the crystal field (CF) formed by ligand atoms. Compared to TM-based SMMs, more dispersed energy level widths of An-based SMMs will give a larger total zero field splitting (ZFS) and thus provide a necessary condition to derive a higher .
View Article and Find Full Text PDFIsostructural Dy(III) and Er(III) complexes [L12Ln(H2O)5][I]3·L12·(CH2Cl2) (Ln = Dy (1), Er (3)) and [L22Ln(H2O)5][I]3·L22·(CH2Cl2)2 (Ln = Dy (2), Er (4)), with distorted pentagonal bipyramidal geometry (D5h) around the central metal were synthesized by utilizing two bulky phosphonamide ligands, adamantyl phosphonamide, (Ad)P(O)(NHiPr)2 (L1) and carbazolyl phosphoramide (Cz)P(O)(NHiPr)2 (L2). The resultant complexes were investigated for their magnetic properties in order to elucidate the impact of modification of the coordinating P-O bond environment either by increasing steric bulk and/or introduction of a third P-N bond at the central phosphorus atom. Magnetic studies revealed substantial energy barriers (Ueff) of 640 K and 560 K for Dy compounds 1 and 2, respectively, rendering them as some of the best-performing air-stable SIMs amongst the class of SIMs with D5h symmetry.
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