Structures and properties of new ferrocene-based paramagnetic anion octamethylferrocenedisulfonate and its TTF salt

Structure and Properties of a BEDT‐TTF‐Based Organic Conductor with a Ferrocene‐Based Magnetic Anion Octamethylferrocenedisulfonate

“…The spins seem to form a square lattice and to interact with each other along the a and b directions (see Figure b). In contrast, the θ value of –5.5 K, caused by the Fc ··· Fc interaction, is larger than those observed in (PPh 4 )ofds ( θ = –0.18 K) and (TTF)ofds · 3.5H 2 O ( θ = –0.30 K) . An unpaired spin on Fc + is localized in an orbital directed along the Cp ··· Fe ··· Cp axis.…”

“…Figure c shows the arrangement of ofds in the anionic layer. Previously we reported the distances between Fe and the cyclopentadienyl ring (Cp) of neutral and monocationic ferrocene parts of ofds as 1.66–1.67 and 1.71–1.73 Å, respectively. The Fe ··· Cp distances in 1 are 1.717 and 1.715 Å for ofds1 and 1.716 and 1.709 Å for ofds2, indicating that both Fc parts are cationic, therefore the ofds molecules are monoanionic.…”

“…Moreover, the ferrocenyl parts of the salts are neutral and therefore diamagnetic. We have also prepared several tetrathiafulvalene (TTF) and bis(ethylenedithio)tetrathiafulvalene (BEDT‐TTF) salts with sulfonates of the ferrocene derivatives, one of which showed metallic conductivity but the ferrocenyl part (Fc) was neutral and diamagnetic …”

“…Recently, we reported a new derivative octamethylferrocenedisulfonate (ofds) . This anion has such a low oxidation potential of –0.08 V vs. SCE that we were able to obtain tetraphenylphosphonium salts of both the yellow dianion where Fc was neutral and the green monoanion where Fc was cationic and paramagnetic.…”