Magnetic molecular charge-transfer salts containing layers of water and tris(oxalato) ferrate(III) anions

We describe the synthesis, crystal structure and conducting properties of two new BEDT-TTF charge transfer salts of tris(oxalato) ferrate(III) containing slightly different numbers of water molecules, (BEDT-TTF)(12)[Fe(C(2)O(4))(3)](2)center dot xH(2)O [x = 15 (I) and 16 (II)]. I crystallizes in the monoclinic space group C2/c, a = 36.017(10), b = 30.880(10), c = 36.183(15) angstrom, alpha = 90, beta = 93.66(3), gamma = 90 degrees, V = 40 161(23) angstrom(3), T = 120(2) K, Z = 8, R1 = 0.0842 [F(2) > 2 sigma(F(2))]; II crystallizes in the same space group, a = 17.9695(15), b = 15.4988(13), c = 36.115(3) angstrom, alpha = 90, beta = 93.720(2), gamma = 90 degrees, V = 10037.1(14) angstrom(3), T = 150(2) K, Z = 4, R1 = 0.0673 [F(2) > 2 sigma(F(2))]. Electrical resistivity measurements show that I and II are semiconductors below 275 K.