Synthesis, crystal structures and magnetic properties of a series of chair-like heterometallic [Fe4Ln2] (Ln = GdIII, DyIII, HoIII, and ErIII) complexes with mixed organic ligands
| Autor: | Yi-Quan Zhang, Hui-Sheng Wang, Qiao-Qiao Long, Zhao-Bo Hu, Feng-Jun Yang, Zhi-Quan Pan, Cheng-Ling Yin, Lin Yue, You Song |
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| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
Ketone Materials science 010405 organic chemistry Ligand Crystal structure 010402 general chemistry 01 natural sciences Magnetic susceptibility 0104 chemical sciences Inorganic Chemistry Magnetic anisotropy Crystallography chemistry Ab initio quantum chemistry methods Molecule Single-molecule magnet |
| Zdroj: | Dalton Transactions. 48:13472-13482 |
| ISSN: | 1477-9234 1477-9226 |
| DOI: | 10.1039/c9dt02638j |
| Popis: | Four chair-like hexanuclear Fe-Ln complexes containing mixed organic ligands, namely, [Fe4Ln2{(py)2CO2}4(pdm)2(NO3)2(H2O)2Cl4]·xCH3CN·yH2O (Ln = GdIII (1, x = 1, y = 0), DyIII (2, x = 1, y = 1), HoIII (3, x = 0, y = 2), and ErIII (4, x = 1, y = 3); (py)2CO2H2 = the gem-diol form of di-2-pyridyl ketone and pdmH2 = 2,6-pyridinedimethanol) have been obtained by employing di-2-pyridyl ketone and 2,6-pyridinedimethanol reacting with FeCl3 and Ln(NO3)3 in MeCN. The structures of 1-4 are similar to each other except for the number of lattice solvent molecules. Four FeIII and two LnIII in these complexes comprise a chair-like core with the "body" constructed by four FeIII ions and the "end" constructed by two LnIII ions. Among the four compounds, 2 shows field-induced single molecule magnet behavior as revealed by ac magnetic susceptibility studies, with the effective energy barrier and the pre-exponential factor of 22.07 K and 8.44 × 10-7 s, respectively. Ab initio calculations indicated that, among 2_Dy, 3_Ho and 4_Er fragments, the energy gap between the lowest two spin-orbit states for 2_Dy is the largest, while the tunneling gap for 2 is the smallest. These might be the reasons for complex 2 exhibiting SMM behavior. Additionally, the orientations of the magnetic anisotropy of DyIII in 2 were obtained by electrostatic calculations and ab initio calculations, both indicating that the directions of the main magnetic axis of Dy1 ions are almost aligned along Dy1-O5 (O5 from the pdm2- ligand). |
| Databáze: | OpenAIRE |
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