Crystal structure and ferromagnetism of (n-C3H7)4N[CoIIFeIII(dto)3] (dto=C2O2S2)

Recently, we have discovered a new type of first order phase transition around 120 K for (n-C3H7)4N[FeIIFeIII(dto)3] (dto=C2O2S2), where the charge transfer transition between FeII and FeIII occurs reversibly. In order to elucidate the origin of this peculiar first order phase transition. Detailed information about the crystal structure is indispensable. We have synthesized the single crystal of (n-C3H7)4N[CoIIFeIII(dto)3] whose crystal structure is isomorphous to that of (n-C3H7)4N[FeIIFeIII(dto)3], and determined its detailed crystal structure. Crystal data: space group P63, a=b=10.044(2) Å, c=15.960(6) Å, α=β=90°, γ=120°, Z=2 (C18H28NS6O6FeCo). In this complex, we found a ferromagnetic transition at Tc=3.5 K. Moreover, on the basis of the crystal data of (n-C3H7)4N[CoIIFeIII(dto)3], we determined the crystal structure of (n-C3H7)4N[FeIIFeIII(dto)3] by simulation of powder X-ray diffraction results.