Synthesis and Structures of Fe^III Complexes Bridged by Cyanorhenium Clusters

The reaction of FeCl(L1) and FeCl(L2) [L1 = bis(3-salicylideneaminopropyl)amine, L2 = bis(3-salicylideneaminopropyl)methylamine] with the Re₆ clusters [Re₆Q₈(CN)₆]^4- (Q = Se, Te) led to the formation of the nanomolecular (≈2.5 nm) compounds [(CN) ₂Re₆Se₈{(CN)Fe(L1)}₄]·7H ₂O (1) and [(CN)₂Re₆Te ₈{(CN)Fe(L2)}₄]·4CH₃CN·4H ₂O (2). Both compounds were characterized by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the triclinic space group P1 with a = 12.2822(10), b = 14.2524(10), c = 15.8474(10) Å, α = 106.093(10)°, β = 101.992(10)°, γ = 92.438(10)°, and Z = 1. Compound 2 crystallizes in the orthorhombic space group Pbca with a = 19.3024(2), b = 16.8134(3), c = 35.9842(6) Å, and Z = 4. In these two compounds, only four pentadentate compartments are bonded to the Re₆ cluster for charge balancing. The magnetic-susceptibility data show that there is no evidence for interactions between Fe^III ions via the central Re₆ cluster in either compound. The observed effective magnetic moments suggest that there are low-spin Fe^III ions and high-spin Fe^III ions mixed in each compound.