Symmetry-breaking substitutions of [Re(CN)8]3- into the centered, face-capped octahedral clusters (CH3OH)24M9M′6(CN)48 (M = Mn, Co; M′ = Mo, W)

The diamagnetic complex [Re(CN)(8)](3-) is shown to react with Mn2+ ions in methanol to generate the centered, face-capped octahedral cluster (CH3OH)(24)Mn9Re6(CN)(48), which is structurally analogous to (CH3OH)(24)Mn9Mo6(CN)(48). Related reactions involving stoichiometric mixtures of octacyanometalate complexes generate the substituted species (CH3OH)(24)Mn9Mo5Re(CN)(48), (CH3OH)(24)Co9Mo5Re(CN)(48), (CH3OH)(24)Mn9Mo3Re3(CN)(48), (CH3OH)(24)Mn9W5Re(CN)(48) and (CH3OH)(24)Co9W5Re(CN)(48), in which the Oh symmetry of the cluster core is broken. Reassessment of the magnetic properties of the Mn9Mo6(CN)(48) cluster confirm that it possesses a ground state spin of S = 39/2, but does not exhibit single-molecule-magnet behavior. Lowering the symmetry of the molecule by substitutions of Re-V at one or three of the Mo-V sites does not lead to an overall increase in the magnetic anisotropy, as probed by ac magnetic susceptibility measurements. A similar result occurs for the other substituted species, with the important exception of the new single-molecule magnet (CH3OH)(24)Co9W5Re(CN)(48), for which the spin reversal barrier is significantly reduced relative to that observed previously in (CH3OH)(24)Co9W6(CN)(48).