Interplay of Structural Flexibility and Crystal Packing in a Series of Paramagnetic Cyclopentadienyl/Dithiolene Mo and W Complexes: Evidence for Molecular Spin Ladders

The structural flexibility of [Cp2M(dithiolene)] complexes (M=Mo, W; dithiolene=dmit2−, dmid2−, dsit2−; the [CpMo(dmid)] complex is depicted on the right) is manifested in various folding angles of the MS2C2 metallacycle in a series of charge-transfer salts with TCNQF4. The evolution of the electronic structures with the folding angle induces different geometries for the dimeric [{Cp2M(dithiolene)+.}2] entities. The organization of these entities in the solid state reveals one-dimensional intermolecular interactions, as confirmed by the magnetic behavior of these salts, which are characteristic of a spin chain or a rare spin ladder motif (shown on the right).