Two copper complexes based on nitronyl nitroxide with different halides: structures and magnetic properties |
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| Authors: | Xiang-Lan Wang Yuan-Xia Li Shuai-Liang Yang Qing-Lun Wang |
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| Affiliation: | 1. College of Chemical Engineering and Materials Science, Tianjin University of Science and Technology, Tianjin, People’s Republic of China;2. Department of Chemistry, Nankai University, Tianjin, People’s Republic of China |
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| Abstract: | Complexes based on different halogen-substituted nitronyl nitroxide radicals and Cu(II), Cu3(hfac)6(NIT-Ph-F)2 (1) and Cu3(hfac)6(NIT-Ph-Cl)2 (2) (hfac = hexafluoroacetylacetonate; NIT-Ph-F = 2-(4′-fluorophenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide; NIT-Ph-Cl = 2-(4′-chlorphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were synthesized and characterized structurally and magnetically. X-ray crystal structure analyses show that 1 and 2 have similar centrosymmetric five-spin structures consisting of three Cu(II) ions bridged by two nitroxide ligands. The Cu(II) is coordinated by six oxygens to form an octahedron, while the five coordination of the terminal Cu(II) ion is square pyramidal. Magnetic measurements reveal strong antiferromagnetic interactions between Cu(II) ions and radicals in 1 (J = ?38.9 cm?1) and weak antiferromagnetic interactions between Cu(II) ions and radicals in 2 (J = ?1.23 cm?1), which may be explained by the bond length of the Cu–Orad (2.468(2) Å) in 1, which is shorter than that (2.514(2) Å) in 2, and the dihedral angle (73.17(1)°) of the plane O7–O8–Cu(2)–O7A–O8A with the moiety O5–N1–C11–N2–O6 in 1 is smaller than (77.82(1)°) in 2. |
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| Keywords: | Copper(II) complexes nitronyl nitroxide crystal structures magnetic properties |
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