Azido-Cyanide Mixed-Bridged Fe-Ni Complexes.

The successful introduction of azide ions as secondary bridges into the Fe-Ni cyanide system afforded two clusters and one unique 4(3),2-ribbon chain: [(bpzpy)Ni(μ-1,1-N){(pzTp)Fe(CN)}]·3HO [; bpzpy = 2,6-bis(pyrazol-1-yl)pyridine, and pzTp = tetrakis(pyrazolyl)borate], [(L1)Ni(μ-1,1,1-OCH)(μ-1,1-N)(HO){(Tp)Fe(CN)}]·2CHOH·HO [; Tp = hydrotris(pyrazolyl)borate, and HL1 = 2,6-bis{(2-hydroxypropylimino)methyl}-4-methylphenol], and [(L2)Ni(μ-1,1-N){(pzTp)Fe(CN)}] (; L2 = 2-{[phenyl(pyridin-2-yl)methylene]amino}ethan-1-amine). Both and feature the centrosymmetric {Fe-Ni-Fe} and {Fe-Ni-Fe} rodlike structures in which the two peripheral [(Tp)Fe(CN)] anions act as monodentate ligands via one cyanide group to link the central azide-bridged [Ni] and [Ni] subunit, respectively, while displays an extended structure of the double-zigzag (4,2-ribbon) chain in which the double end-on azide-bridged trinuclear [Ni] subunits serve as the 4-connected nodes. Magnetic study revealed that intramolecular ferromagnetic coupling is dominated by the azide or cyanide bridges in all of the complexes. Remarkably, complex behaves as a single-molecule magnet with an effective energy barrier of 16.5 cm at zero dc field, while complex exhibits metamagnetism with a hidden spin canting property below 12 K.