First radical cation salt of paramagnetic transition metal complex containing TTF as ligand, [CuII(hfac)2(TTF-py)2](PF6)•2CH2Cl2 (hfac = hexafluoroacetylacetonate and TTF-py=4-(2-tetrathiafulvalenyl-ethenyl)pyridine)

The preparation, X-ray crystal structure, EPR data, and magnetic measurement of [Cu-II(hfac)(2)(TTF-py)(2)](PF6).2CH(2)Cl(2), a novel material where the conducting and the localized spin systems are covalently linked through conjugated bridges, are reported. The partial oxidation of the TTF-type organic donor ligand yielded the first radical cation salt of a paramagnetic transition metal complex. Moreover, this compound shows a mixed valence state at the unimolecular level, and additionally, the arrangement of the molecules in the crystal structure revealed the presence of isolated mixed valence TTF dimers.