Costes Jean-Pierre, Auchel Magali, Dahan Françoise, Peyrou Viviane, Shova Sergiu, Wernsdorfer Wolfgang
Laboratoire de Chimie de Coordination du CNRS, UPR 8241, liée par conventions à l'Université Paul Sabatier et à l'Institut National Polytechnique de Toulouse, 205 route de Narbonne, 31077 Toulouse Cedex, France.
Inorg Chem. 2006 Mar 6;45(5):1924-34. doi: 10.1021/ic050587o.
The copper(II)-gadolinium(III) and copper(II)-terbium(III) complexes studied in this report derive from disymmetric trianionic ligands abbreviated H3Li (i = 4-6). These ligands are obtained through reaction of different aldehydes with "half-units" having an amide function, the latter resulting from the monocondensation of different diamines with phenyl 2-hydroxy-3-methoxybenzoate. Upon deprotonation, the Li ligands (i = 4-10) possess an inner N2O2 coordination site with one amido, one imine, and two phenoxo functions, an outer O2O2 or O2O coordination site, and an amido oxygen atom positioned out of these two sites. The trianionic character of such ligands yields original anionic complexes in the presence of copper(II) or nickel(II) ions, with a 1/1 L/M stoichiometry. The crystal and molecular structures of four complexes, two 3d (1, 5) and two 3d-4f (12, 13) complexes, have been determined. Complex 1 crystallizes in the monoclinic space group C2/c: a = 27.528(2) A, b = 7.0944(7) A, c = 22.914(2) A, beta = 92.130(6) degrees , V = 4471.9(7) A(3), Z = 8 for C(21.5)H(27)CuKN(2)O(6.5). Complex 5 crystallizes in the monoclinic space group P2(1)/n (No. 14): a = 11.0760(9) A, b = 21.454(2) A, c = 15.336(1) A, beta = 101.474(1) degrees , V = 3571.5(5) A(3), Z = 4. Complex 12 crystallizes in the triclinic space group P (No. 2): a = 8.682(2) A, b = 11.848(2) A, c = 11.928(2) A, alpha = 81.77(3) degrees , beta = 89.17(3) degrees , gamma = 85.49(3) degrees , V = 1210.6(4) A(3), Z = 2 for C20H22CuN5O11Tb. Complex 13 belongs to the monoclinic space group C2/c: a = 25.475(5)A, b = 12.934(3)A, c = 15.023(3) A, beta = 91.06(3) degrees , V = 4949.02A3, Z = 8 for C21H25CuN4O12Tb. The structural determinations confirm that the dinuclear entities involved in 12 and 13 are disposed in a head-to-tail arrangement to give tetranuclear complexes in which the copper and lanthanide ions are positioned at the vertexes of a rectangle. In the [Cu-Gd]2 species, there are two different ferromagnetic Cu-Gd interactions. The stronger one is supported by the double phenoxo bridge (CuO2Gd) while the weaker one corresponds to the single amido bridge (Cu-N-C-O-Gd). Replacement of gadolinium ions with anisotropic terbium ions yields tetranuclear entities showing slow relaxation of magnetization and magnetization hysteresis. Detailed relaxation and hysteresis loop studies establish single-molecule magnet (SMM) behavior which is influenced by weak intermolecular interactions.
本报告中研究的铜（II）-钆（III）和铜（II）-铽（III）配合物源自缩写为H3Li（i = 4 - 6）的不对称三阴离子配体。这些配体通过不同醛与具有酰胺功能的“半单元”反应获得，后者由不同二胺与2 - 羟基 - 3 - 甲氧基苯甲酸苯酯的单缩合反应产生。去质子化后，Li配体（i = 4 - 10）具有一个内部N2O2配位位点，带有一个酰胺基、一个亚胺基和两个酚氧基功能，一个外部O2O2或O2O配位位点，以及一个位于这两个位点之外的酰胺氧原子。此类配体的三阴离子特性在存在铜（II）或镍（II）离子时产生原始的阴离子配合物，化学计量比为1/1 L/M。已确定四种配合物的晶体和分子结构，两种3d（1, 5）和两种3d - 4f（12, 13）配合物。配合物1结晶于单斜空间群C2/c：a = 27.528(2) Å，b = 7.0944(7) Å，c = 22.914(2) Å，β = 92.130(6)°，V = 4471.9(7) ų，对于C(21.5)H(27)CuKN(2)O(6.5)，Z = 8。配合物5结晶于单斜空间群P2(1)/n（编号14）：a = 11.0760(9) Å，b = 21.454(2) Å，c = 15.336(1) Å，β = 101.474(1)°，V = 3571.5(5) ų，Z = 4。配合物12结晶于三斜空间群P（编号2）：a = 8.682(2) Å，b = 11.848(2) Å，c = 11.928(2) Å，α = 81.77(3)°，β = 89.17(3)°，γ = 85.49(3)°，V = 1210.6(4) ų，对于C20H22CuN5O11Tb，Z = 2。配合物13属于单斜空间群C2/c：a = 25.475(5)Å，b = 12.934(3)Å，c = 15.023(3) Å，β = 9
