Crystal Structures and Magnetic Properties of d-pπ Organic Conductors, (EDT-TTF)4CoCl4(1,1,2-TCE)x and Related Materials

A new series of d-pπ organic conductors ((EDT-TTF)4CoX4(solvent)x [EDT–TTF = ethylenedithiotetrathiafulvalene; X = Cl, Br; solvent = 1,1,2–TCE (trichloroethane), CH2Cl2]) consists of anions including 3d localized spins and donors containing itinerant pπ electrons. The crystal and band structure analyses show that these salts have face-to-face regular donor stacking, the so-called β-type donor arrangement, and that the calculated Fermi surfaces are closed due to relatively large interchain interactions. Resistivity measurements show the metallic behaviors down to 80 K [(EDT-TTF)4CoCl4(1,1,2-TCE)x], 235 K [(EDT-TTF)4CoCl4(CH2Cl2)x], 110 K [(EDT-TTF)4CoBr4(1,1,2-TCE)x], and 190 K [(EDT-TTF)4CoBr4(CH2Cl2)x], respectively. Especially, for (EDT-TTF)4CoCl4(1,1,2-TCE)x, the ESR measurements indicate that the linewidth attributed to EDT-TTF+ increases and that the g-value decreases rapidly when the resistivity starts increasing below 80 K, owing to substantially the dipole–dipole interaction between pπ (EDT-TTF+)-...

[1]  Takehiko Mori,et al.  Systematic study of the electronic state in θ-type BEDT-TTF organic conductors by changing the electronic correlation , 1998 .

[2]  T. Enoki,et al.  MOLECULAR MAGNETS BASED ON ORGANIC CHARGE TRANSFER COMPLEXES , 1997 .

[3]  T. Kondo,et al.  Structure and Physical Properties of EDT-TTF Salts , 1997 .

[4]  T. Enoki,et al.  Magnetic Properties of Organic Conductor (BEDT-TTF)3CuBr4. , 1996 .

[5]  T. Naito,et al.  New BETS Conductors with Magnetic Anions (BETS = bis(ethylenedithio)tetraselenafulvalene) , 1996 .

[6]  Y. Maruyama,et al.  Physical and chemical properties of MSSe-TTF and EDSe-TTF salts , 1994 .

[7]  G. Papavassiliou,et al.  Structures of the new superconductor (MDTTTF)2AuI2 (Tc = 4.5 K) and the organic metal (EDTTTF)2AuI2 (MDTTTF = methylenedithiotetrathiafulvalene and EDTTTF = ethylenedithiotetrathiafulvalene) , 1990 .

[8]  Reizo Kato,et al.  Crystal and electronic structures of conductive anion-radical salts, (2,5-R1R2-DCNQI)2Cu (DCNQI = N,N'-dicyanoquinonediimine; R1, R2 = CH3, CH3O, Cl, Br) , 1989 .

[9]  H. Inokuchi,et al.  Metal-to-semiconductor transition of an organic metal, (EDT-TTF)2AuBr2 , 1989 .

[10]  Kobayashi,et al.  Electrical conductivity, thermoelectric power, and ESR of a new family of molecular conductors, dicyanoquinonediimine-metal , 1988, Physical review. B, Condensed matter.

[11]  M. Firestone,et al.  Ambient-pressure superconductivity at the highest temperature (5 K) observed in an organic system: β-(BEDT-TTF)2AuI2 , 1985 .

[12]  F. Behroozi,et al.  Ambient-pressure superconductivity at 2.7 K and higher temperatures in derivatives of (BEDT-TTF)2IBr2: synthesis, structure, and detection of superconductivity , 1984 .

[13]  Takehiko Mori,et al.  The Intermolecular Interaction of Tetrathiafulvalene and Bis(ethylenedithio)tetrathiafulvalene in Organic Metals. Calculation of Orbital Overlaps and Models of Energy-band Structures , 1984 .