BEDT-TTF salts of the unsymmetrical [M(tfadt)2]− dithiolene complexes (M = Ni, Au; tfadt = S2C2(CN)(CF3))

Two closely related 1:1 salts are obtained upon electrocrystallization of BEDT-TTF (BEDT-TTF: bis(ethylenedithio)tetrathiafulvalene) in the presence of the isosteric [M(tfadt)2]− dithiolene complexes (tfadt: 1-trifluoromethyl-2-cyano-1,2-dithiolato), which essentially differ by their spin state, S = 0 in [Au(tfadt)2]−, S = 1/2 in [Ni(tfadt)2]−. In both [BEDT-TTF][M(tfadt)2] salts, the BEDT-TTF radical cations form chains with a strong lateral overlap and strong antiferromagnetic interactions while the paramagnetic anions in the nickel-containing salt [BEDT-TTF][Ni(tfadt)2] are essentially non-interacting. The structural differences between the nickel and gold complexes are analyzed and discussed.