Molecular materials based upon organic pi-donors and magnetic anions

Electrochemical combination of the magnetic dinuclear anion [MM'(C2O4)(NCS) (8)](4-) (MM' = CrCr, CrFe) or paramagnetic mononuclear anion [Cr(NCS)(6)]( 3-) with the ET organic pi-donor (ET = BEDT-TTF = bis(ethylenedithio)tetrat hiafulvalene) gives rise to two new series of molecular hybrid salts formul ated (ET)(5)[MM'(C2O4) (NCS)(8)] (MM' = CrCr (1), CrFe (2)), (ET)(8)[MM' (C 2O4) (NCS)(8)] (3), (ET)(5.5)[Cr(NCS)(6)] (4) and (ET)(5)[(C2H5)(4)N] [Cr(N CS)(6)] (THF) (5) (THF = tetrahydrofuran). The crystal structures consist o f alternating organic and inorganic layers. The organic part does not produ ce any detectable effect on the magnetic properties coming from the inorgan ic sublattice. They indicate the presence of antiferromagnetic coupling in the homometallic dimers (1 and 3), while the coupling is ferromagnetic in t he heterometallic one (2). Conductivity measurements reveal a metallic stat e for compounds 3 and 5.