Terbium Triangle Bridged by a Triazole Nitronyl Nitroxide Radical with Single-Molecule-Magnet Behavior.

An unprecedented cyclic TbIII-radical cluster, [Tb3(hfac)6(4-Me-3-NITtrz)2(OH)3] (1), has been self-assembled from Tb(hfac)3·2H2O and 4-Me-3-NITtrz in the presence of Cu(hfac)2·2H2O. Alternating-current magnetic studies show that the Tb3 cluster displays a dual slow relaxation of magnetization behavior under a zero direct-current (dc) field and a single relaxation process under an induced dc field with an effective energy barrier of 14 K, representing the first triangle 2p-4f cluster with a slow magnetic relaxation property.

Synthesis of a series of hetero-multi-spin Ln2Cu3 complexes based on a methyl-pyrazole nitronyl nitroxide radical with slow magnetic relaxation behaviors.

Multinuclear hetero-tri-spin complexes based on a methyl-pyrazole nitronyl nitroxide radical, namely, [Ln2Cu3(hfac)12(4-NIT-MePyz)4] (Ln = Gd(1), Tb(2), Dy(3); hfac = hexafluoroacetylacetone; 4-NIT-MePyz = 2-{4-(1-methyl)-pyrazolyl}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been successfully obtained through a one-pot reaction of the radical ligand (4-NIT-MePyz) with Cu(hfac)2 and Ln(hfac)3. These 2p-3d-4f complexes exhibit five-nuclear structures with the sequence [Cu-Rad-Ln-Rad-Cu-Rad-Ln-Rad-Cu], in which each 4-NIT-MePyz radical acting as a bidentate bridging ligand is coordinated to one Ln(hfac)3 unit through one oxygen atom of the NO groups and to one Cu(hfac)2 unit with one nitrogen atom from the pyrazole ring. For complex 1, based on the spin Hamiltonian calculations and MAGPACK program, it is concluded that there exist ferromagnetic couplings between GdIII and NIT radicals, as well as between CuII and free radicals with J1 = 6.8(1) and J3 = 1.3(2) cm-1, respectively, and antiferromagnetic interactions between radical and radical with J2 = -2.8(5) cm-1. Complex 2 shows frequency-dependent out-of-phase signals under a zero or 2000 Oe dc field indicating single-molecule magnetic behavior.

Two 3D Cobalt(II) Metal-Organic Frameworks with Micropores for Selective Dye Adsorption.

Two porous coordination polymers, {[Co0.5(TBC)]·2DMF} n (1) and {[Co(TBC)Cl0.5(CH3OH)]·0.5Cl} n (2), were synthesized via the solvothermal reaction of cobalt(II) salts and 3,5-bis(1 H-1,2,4-triazol-1-yl)benzenecarboxylic acid. Single-crystal X-ray diffraction analyses exhibited that complex 1 contains rtl three-dimensional (3D) skeleton and one-dimensional channels with large apertures, while complex 2 displays a novel 2-nodal 3,6-linked 3D structure with a Schläfli sign of {4.82}2{46.89} and contains micropores. Meanwhile, compound 2 shows selective adsorption properties of anionic methyl orange in a water solution. The dye adsorption studies of 1 and 2 revealed that the porous character and charge properties of metal-organic frameworks are two important factors heavily influencing dye adsorption.

Slow relaxation of the magnetization observed in mononuclear Ln-radical compounds with D4d geometry configurations.

The combination of LnIII ions (GdIII, TbIII or DyIII) and a pyrazole nitronyl nitroxide radical results in three isomorphous complexes, namely, [Ln(hfac)3(NIT-Pyz)]2 (Ln = Gd(1), Tb(2), Dy(3); hfac = hexafluoroacetylacetone; NIT-Pyz = 2-{3-pyrazolyl}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide). Single crystal X-ray diffraction studies revealed that all of them are composed of two crystallographically independent mononuclear systems, in which the central LnIII ions are coordinated by three hfac and one bidentate chelating NIT-Pyz radical. The central LnIII ions are all in square antiprism geometry (D4d) polyhedron configurations. Based on the spin Hamiltonian calculations, there exist antiferromagnetic couplings in the GdIII-NIT radical system in complex 1. Complexes 2 and 3 show frequency-dependent out-of-phase signals in a zero field indicating single-molecule magnetic behavior. Moreover, Tb's complex (2) shows a single thermal relaxation process with an energy barrier of 26 K. For Dy's complex (3), the Orbach and Raman processes both contribute to the magnetic relaxation behaviors.

Lanthanide Tetranuclear Cage and Mononuclear Cocrystalline Nitronyl Nitroxide Complex with Single-Molecule-Magnet Behavior.

The first tetranuclear metallacage and mononuclear cocrystalline DyIII-radical complex was synthesized and characterized. The metallacage in [Dy4(hfac)8(IMPhThio)2(OH)4][Dy(hfac)3(NITPhThio)2] consists of Dy(hfac)2+ groups bridged by OH- and the IMPhThio radical. Field-induced single-molecule-magnet behavior was observed in the nitronyl nitroxide radical-bridged polynuclear complex.

A family of multi-spin rare-earth complexes based on a triazole nitronyl nitroxide radical: synthesis, structure and magnetic properties.

The combination of LnIII ions (GdIII, TbIII or DyIII) and a triazole nitronyl nitroxide radical (4-Me-3-NITtrz) as spin carriers results in two mononuclear and one binuclear compounds, namely, [Ln(hfac)3(4-Me-3-NITtrz)(H2O)] (Ln = Gd(1), Tb(2); hfac = hexafluoroacetylacetone; 4-Me-3-NITtrz = 2-[3-(4-methyl-l,2,4-triazolyl)]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) and [Dy(hfac)2(4-Me-3-NITtrz)2][Dy(hfac)4]·CHCl3. Compounds 1 and 2 are isostructural and crystallize in the P1̄ space group, whereas compound 3 crystallizes in the P21/n space group. In 1 and 2, the central LnIII ions are nine-coordinated (LnNO8) in a distorted spherical capped square antiprism geometry (C 4v) finished by three bischelate hfac anions and one bidentate triazole radical and one aqua molecule. While 3 is a mixed-coordinated binuclear compound with Dy1 in a triangular dodecahedron (D 2d) coordination sphere and Dy2 in a biaugmented trigonal prism (C 2v) coordination sphere. Magnetic studies show that compound 2 exhibits field-induced single-molecule magnet (SMM) behavior.

[Clinical applications of the postfemur island flap pedicled with the postfemur neurocutaneous nutrient vessel].

OBJECTIVE: To investigate the application of the island flap based on the postfemur neurocutaneous nutrient vessel. METHODS: The flap was designed and applied to repair the defects in the gluteal, popliteal fossa or the bilateral postfemur areas. A total of 11 cases (12 defects) were treated with this method. The size of the defects ranged from 4.0 cm x 7.8 cm to 8.3 cm x 16.6 cm. RESULTS: Of the 12 defects, 9 achieved complete success. Epidermal necrosis occurred in the distal part of the flap in 3 defects owing to venous stasis, which were cured with skin grafting. Postoperative follow-up for 8-19 months showed that the appearance, texture, and function of the flap were satisfactory. CONCLUSIONS: The advantages of the flap lie in the reliable blood supply, constant anatomy, and without sacrificing a major artery. The key points for the flap survival are utilizing the "Superficial vein-nutrient vessel of the cutaneous nerve system" and retaining a comet tail-shaped soft-tissue pedicle in the flap creation.