Syntheses, crystal structures and physical properties of conducting salts (BEDT-TTF) 2X (X = CF 3SO 3 or p-CH 3C 6H 4SO 3)

Abstract

Two new conducting BEDT-TTF salts with organic anions, (BEDT-TTF) 2X, where X = CF 3SO 3 (1) or p-CH 3C 6H 4SO 3 (2), are described. Crystal data: (1), monoclinic, space group P2 1/n, a = 6.649(1), b = 33.050(3), c = 15.018(1) A ̊ , ß = 90.98(1)°, V = 3299.8 A ̊ 3 and Z = 4 ; (2), monoclinic, space group P2, a = 7.785(1), b = 6.697(2), c = 34.402(8) A ̊ , ß = 91.10(2)° , V = 1793.2 A ̊ 3 and Z = 2 . The conductivity of (1) shows two phase transitions at 218 and 306 K and exhibits a temperature-dependent activation energy at all temperatures from 150 – 400 K. The conductivity of (1) between 220 and 400 K suggests an analogy with the inorganic quasi-one-dimensional material K 2[Pt(CN) 4]Br 0.3·3H 2O. (2) is semiconducting in the temperature range 150 – 300 K, σ 300K = 10 −3 S cm −1 and E g = 0.26 eV.