Tetrachloroferrate (III) salts of BDH-TTP [2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene] and BDA-TTP [2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene]: Crystal structures and physical properties

摘要

Three FeCl4 salts based on non-tetrathiafulvalene (TTF) donors, 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene (BDH-TTP) and 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP), have been prepared and characterized as kappa-(BDH-TTP)(2)FeCl4, beta-(BDA-TTP)(2)FeCl4, and (BDA-TTP)(3)FeCl4 - PhCl. The kappa-(BDH-TTP)(2)FeCl4 salt, with a room-temperature conductivity (sigma(rt)) of 39Scm(-1), is metallic down to 1.5 K, and its magnetic susceptibility obeys the Curie-Weiss law with a Curie constant (C) of 4.25 emu K mol(-1) and a Weiss constant (theta) of 0.041K. beta-(BDA-TTP)(2)FeCl4 exhibits metallic behavior (sigma(rt)=9.4Scm(-1)) with a sharp metal-to-insulator (MI) transition (T-MI=113K) and antiferromagnetic ordering with the Neel temperature of near 8.5K, whereas the solvated (BDA-TTP)(3)FeCl4 - PhCl salt is a semiconductor with a thermal activation energy of 0.11eV (sigma(rt)= 2.0 x 10(-2)Scm(-1)) and exhibits Curie-Weiss behavior (C = 4.42 emu K mol(-1), theta = -0.35 K). (C) 2002 Elsevier Science (USA). [References: 15]