Novel Heterometallic Fe-Ru-2-Fe Arrays Via "Complex Of Complexes" Approach

Four tetranuclear heterometallic compounds, [(Tp)Fe(CN)(3)](2)[Ru-2(DMBA)(4)] (1), [(MeTp)Fe(CN)(3)](2)[Ru-2(DMBA)(4)] (2), [(BuTp)Fe(CN)(3)](2)[Ru-2(DMBA)(4)] (3), and [(PhTp)Fe(CN)(3)](2)[Ru-2(DMBA)(4)] (4) [DMBA = N,N'-dimethylbenzamidinate, Tp = (hydrotris(pyrazolyl)borate, MeTp = (methyltris(pyrazolyl)borate, (i)BuTp = (2-methylpropyltris(pyrazolyl)borate, and PhTp = (tris(pyrazolyl)phenylborate)] were prepared from the combination of Ru-2(DMBA)(4)(NO3)(2) and an appropriate [(RTp)Fe(CN)(3)](-). Molecular structures of compounds 1-4 were established using single-crystal X-ray diffraction, and all feature a linear Fe-C N-Ru-Ru-N C-Fe array. The magnetic study revealed that the temperature dependence of T-chi M is mostly attributed to the zero-field splitting of the Ru-2 center, indicating the absence of strong spin coupling among three metallic centers. The electronic independence was further confirmed by the vis-NIR spectroscopic studies. Also described are the voltammetric properties of these compounds.