S Noro, H Miyasaka, S Kitagawa, T Wada, T Okubo, M Yamashita, T Mitani
INORGANIC CHEMISTRY 44 (1) 133 - 146 0020-1669 2005/01
[Not refereed][Not invited] By utilizing the novel metalloligand L(Cu) [Cu(2,4-pydca)(2)](2-) (2,4-pydca (2-) = pyridine-2,4-dicarboxylate), which possesses two kinds of coordination groups, selective bond formation with the series of the first-period transition metal ions (Mn(II), Fe(II), Co(II), Cu(II), and Zn(II)) has been accomplished. Depending on the coordination mode of 4-carboxylate with Co(II), Cu(II), and Zn(II) ions, L(Cu) forms a one-dimensional (1-D) assembly with a repeating motif of [-M-O(2)C-(py)N-Cu-N(py)-CO(2)-]: {[ZnL(Cu)(H(2)O)(3)(DMF)](.)DMF}(n) (2), [ZnL(Cu)(H(2)O)(2)(MeOH)(2)](n) (3), and {[ML(Cu)(H(2)O)(4)](.)2H(2)O}(n) (M = Co (4), Cu (5), Zn (6)). The use of a terminal ligand of 2,2'-bipyridine (2,2'-bpy), in addition to the Cu(II) ion, gives a zigzag 1-D assembly with the similar repeating unit as 4-6: {[Cu(2,2'-bpy)L(Cu)](.)3H(2)O}(n) (9). On the other hand, for Mn(II) and Fe(II) ions, L(Cu) shows a 2-carboxylate bridging mode to form an another 1-D assembly with a repeating motif of [-M-O-C-O-Cu-O-C-O-]: [ML(Cu)(H(2)O)(4)](n) (M = Mn (7), Fe (8)). This selectivity is related to the strength of Lewis basicity and the electrostatic effect of L(Cu) and the Irving-Williams order on the present metal ions. According to their bridging modes, a variety of magnetic properties are obtained: 4, 5, and 9, which have the 4-carboxypyridinate bridge between magnetic centers, have weak antiferromagnetic interaction, whereas 7 and 8 with the carboxylate bridge between magnetic centers reveal 1-D ferromagnetic behavior (Cu(II)-M(II); M(II) = Mn(II), J/k(B) = 0.69 K for 7; M(II) = Fe(II), J/k(B) = 0.71 K for 8).