Heterometallic complexes based on the mixed bridging ligands of tricyanometalate and terephthalate: syntheses, structures, and magnetic properties.

With the use of the tailored tricyanometalate precursors [(L)Fe(CN)(3)](-) (L = Tp, tris(pyrazolyl)hydroborate; L = i-BuTp, 2-methylpropyltris(pyrazolyl)borate) and terephthalate (ta) units as the mixed bridging ligands, a new one-dimensional (1D) chain polymer {[(Tp)(2)Fe(2)(CN)(6)Cu(2)(ta)(dmbpy)(2)] x 7 H(2)O}(n) (1), a pentanuclear heterometallic cluster [(Tp)(2)Fe(2)(CN)(6)Cu(3)(phen)(3)(ta)(2)(MeOH)(H(2)O)(2)] x 8 H(2)O (2), and a tetranuclear heterometallic cluster [(i-BuTp)(2)Fe(2)(CN)(6)Cu(2)(ta)(phen)(2)(EtOH)(2)] x 2 MeOH x H(2)O (3) (dmbpy = 4,4'-dimethyl-2,2'-bipyridyl, phen = 1,10-phenanthroline) have been synthesized and structurally characterized. The Fe(III) and Cu(II) ions are bridged by cyanides, and the Cu(II) ions are further linked by terephthalate to form the 1D chain polymer, the pentanuclear cluster, and the tetranuclear cluster for complexes 1-3, respectively. All complexes show ferromagnetic interactions between the Fe(III) and Cu(II) ions. Complex 1 shows metamagnetic behavior with the critical field of about 1.2 T at 1.8 K.