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-methylpropyltrls(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)₆Cu ₃(Phen)₃(ta)₂(MeOH)(H₂O) ₂] · 8H₂O (2), and a tetranuclear heterometallic cluster [(i-BuTp)₂Fe₂-(CN)₆Cu ₂(ta)(phen)₂(EtOH)₂] 2MeOH · H ₂O (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 metamagnetlc behavior with the critical field of about 1.2 T at 1.8 K.