Characterization of quasi-1D conductors, (BDTFP)2X(Phcl)0.5 (x = PF6, AsF6)

Abstract We present the low-temperature crystal structures of (BDTFP) 2 PF 6 and (BDTFP) 2 AsF 6 below the phase transition temperatures ( T p ). In the former compound, the c -axis is doubled and thus the dimerized structure changed into a tetramerized structure. At the same time, a new charge-transfer (CT) transition appears at 7000–8000 cm −1 . These two findings are consistent with the non-magnetic state below T p . In the latter, on the other hand, the dimerized structure is maintained below T p , and instead AsF 6 ion rotates along with the ca. 10° rotation of BDTFP. This structural change is the origin of the first-order phase transition to a paramagnetic state.