Multi-layered molecular charge-transfer salts containing alkali metal ions

The synthesis, crystal structure and physical properties of two new BEDT-TTF charge-transfer salts containing the tris( oxalato) ferrate( III) anion are described. The most commonly found tris( oxalato) metallate( III) salts of BEDT-TTF contain alternating layers of BEDT-TTF cations and tris( oxalato) metallate anions, but the two salts reported here are multi-layered structures. Compound I is of the type ABCDABCDA as observed previously in the proton-conducting compound beta "-( BEDT-TTF)(4)[Fe(C2O4)(3)](2)center dot 18-crown-6 center dot 9H(x)O and the alpha -beta family of salts alpha,beta "-(BEDT-TTF)(4)[(NH4)Ga/Fe(C2O4)(3)]center dot G ( G = PhN(CH3)COH, PhCH2CN and PhCOCH3). In a "'( BEDT-TTF)(9)[Fe(C2O4)(3)](8)Na-18(H2O)(24) (I) the A layers consist of only BEDT-TTF, B/ D layers consist of tris( oxalato) ferrate( III) and sodium, and the C layers consist of sodium and water. In alpha-(BEDT-TTF)(10)(18-crown-6)(6)K-6[Fe(C2O4)(3)](4)(H2O)(24) (II) the packing is of a type not seen before, ABCBABCBA. The A layers in II consist of only BEDT-TTF, B layers consist of tris( oxalato) ferrate( III), potassium, water and 18-crown-6, and C layers consist of 18-crown-6, potassium and water. Both salts are semiconductors between room temperature and 140 K.