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)2Fe2(CN)6Cu2(ta)(dmbpy)2]·7H2O}n (1), a pentanuclear heterometallic cluster [(Tp)2Fe2(CN)6Cu3(phen)3(ta)2(MeOH)(H2O)2]·8H2O (2), and a tetranuclear heterometallic cluster [(i-BuTp)2Fe2(CN)6Cu2(ta)(phen)2(EtOH)2]·2MeOH·H2O (3) (dmbpy = 4,4′-dimethyl-2,2′-bipyridyl, phen = 1,10-phenanthroline) have been synthesized and structurally characterized. The FeIII and CuII ions are bridged by cyanides, and the CuII 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 FeIII and CuII ions. Complex 1 shows metamagnetic behavior with the critical field of about 1.2 T at 1.8 K.