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Syntheses, crystal structures, and magnetic properties of two cyclic dimer M2L2 complexes constructed from a new nitronyl nitroxide ligand and M(hfac)2 (M = Cu, Mn) |
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| Authors: | Jian-Ying Zhang Cai-Ming Liu De-Qing Zhang Dao-Ben Zhu |
| Institution: | a Beijing National Laboratory for Molecular Science, Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, PR China b State Key Laboratory of Rare Earth Materials and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China c Graduate School, Chinese Academy of Sciences, Beijing 100049, PR China |
| Abstract: | Two new binuclear radical complexes derived from a new long nitronyl nitroxide ligand, 2-4-(5-pyrimidyl)phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (4-NITPhPyrim), and M(hfac)2 (M2+ = Cu2+, Mn2+; hfac− = hexafluoroacetylacetonato), Cu(hfac)2(4-NITPhPyrim)]2 · 4H2O (1) and Mn(hfac)2(4-NITPhPyrim)]2 · 4H2O (2), were synthesized as well as characterized structurally and magnetically. X-ray analysis indicates that 1 and 2 are rectangle-like centrosymmetric dimer M2L2 complexes. Magnetic measurements indicate that there are two types of magnetic exchanges in 1: the ferromagnetic (FM) exchange between the Cu(II) ion and the directly bonded nitroxide unit (J1 = 24.20 cm−1) and the weak FM exchange of Cu-NIT through the pyrimidine and phenyl rings (J2 = 0.62 cm−1). Besides the strong antiferromagnetic (AFM) coupling between the Mn(II) ion and the directly bonded nitroxide unit (J = −87.61 cm−1), there is a weak FM interaction between the two Mn-NIT pairs (θ = 0.39 K) in 2. |
| Keywords: | Nitronyl nitroxide Cyclic dimer complexes Crystal structures Magnetic properties |
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