TTF based charge transfer salts of [M(NCS)4(C9H7N)2]− where M = Cr, Fe and C9H7N = isoquinoline; observation of bulk ferrimagnetic order

Abstract

Three new charge transfer salts of BEDT-TTF and TTF with the counter ions [M(NCS)4(C9H7N)2]− (M = Cr, Fe; C9H7N = isoquinoline) are described. The materials are prepared by standard electrocrystallisation techniques. The nature of the anion is verified in the crystal structure of the salt [C9H8N][Cr(NCS)4(C9H7N)]·C12H24O6·H2O which is used as the electrolyte when M = Cr. All of the charge transfer salts display long range ferrimagnetic order originating from the interaction between M (S = 3/2 or S = 5/2) and the donor (S = 1/2). The measured critical temperatures are 4.2 K (BEDT-TTF, M = Cr), 4.5 K (BEDT-TTF, M = Fe) and 8.9 K (TTF, M = Cr). Each of the compounds also shows a modest magnetic hysteresis of 338, 18 and 75 Oe for BEDT-TTF salts of M = Cr, Fe and the TTF salt of Cr, respectively.