Paramagnetic Cp/dithiolene complexes as molecular hinges:: Interplay of metal/ligand electronic delocalization and solid-state magnetic behavior

Paramagnetic, flexible organometallic dithiolene complexes associating cyclopentadienyl (Cp) and dithiolate (dt) ligands, such as CpM(dt), Cp2M(dt), or CpM(dt)(2), are investigated in the solid state through their structural and magnetic properties. The degree of delocalization of the spin density between the metal and the dithiolene fragments in a given complex, its varying molecular geometry and frontier orbitals, and the structures adopted in the solid state are intimately correlated and adapt mutually to each other. A variety of magnetic structures follows, from noninteracting spins to dyads, spin chains, spin ladders, or antiferromagnetic ground state, the detailed properties of which are highly sensitive to "minor" molecular modifications.