H. Endres

Synthesis, Structure and Physical Properties of a Two-Dimensional Organic Metal, Di[bis(ethylenedithiolo)tetrathiofulvalene] triiodide, (BEDT-TTF)+ 2 I− 3

Abstract Electrical oxidation of bis(ethylenedithiolo)tetrathiofulvalene (BEDT-TTF) 1 in a nitrogen saturated tetrahydrofurane solution containing (n-C4H10)4N+I3 as electrolyte results in the deposition of crystal plates of (BEDT-TTF)+ 2I3 (C10H8S8)2I3. These two dimensional crystals are triclinic, space group P1, a = 9.211(2), b=10.850(4), c = 17.488(5) A, α=96.95(2), β = 97.97(2), γ = 90.75(2)°, V = 1717 A3, Mr = 1150.01, Z=2, Dx =2.22 g cm−3. Rw = 0.037 for 2462 observed reflections. Sheets of alternating cations and anions occur in the compound. The most prominent intermolecular S-S contacts (∼3.5A) are found between the stacks of BEDT-TTF. The stacking of the molecules and the interstack contacts give the compound a two-dimensional character which influences the physical properties. The room temperature conductivities in the ab plane range typically between 60 and 250 (ω cm)−1. The conductivity anisotropy in this plane is small with a ratio of σa/σb⩽ 2, while in the direction perpendicular to the ab-...

Synthese und Röntgenstrukturanalyse des Phenanthro[9,10-c]-1,2,5-telluradiazols / Synthesis and X-Ray Structure Analysis of Phenanthro[9,10-c]-1,2,5-telluradiazole

Abstract The synthesis of 1 by reaction of phenanthro[9,10-c]-1,2,5-selenadiazole with ethylmagnesium-bromide and TeCI4 is described; the X-ray structure analysis is reported.

Organic Metals from Simple Aromatic Hydrocarbons: Perylene Radical Salts

Crystal structures, temperature dependent thermopower and conductivity measurements of several metallic perylene radical salt phases are discussed.

The preparation of new metallic charge-transfer complexes: anthra [9.1-cd:10.5-c'd'] bis [1.2] dithiol (TTA), -diselenol (TSA) and their polyiodides

The donors TTA and TSA were prepared starting from 1.5-dichloro-9.10-anthracenedione which was converted into 1.5.9.10-tetrachloroan-thracene (TCA) by two alternating chlorination and elimination steps. TCA was reacted under a dry argon atmosphere with suspensions of Na2S2 and Na2Se2 to yield TTA and TSA, respectively. Action of elemental iodine gives highly conductive polyiodides of both donors. Single crystals of TSA·I1.2 actually behave metallic between 220 and 300 K. The X-ray structure of TSA and TSA·I1.2 allows a comparison of intermolecular distances in the neutral and the partially oxidized, ionic stacks of the donor.

Highly conducting phenazine-doped 5,10-dihydro-5,10-dimethylphenaziniumyl–TCNQ. Physical properties and crystal and molecular structure

5,10-Dihydro-5,10-dimethylphenaziniumyl 7,7,8,8tetracyano-p-quinodimethanide (M2P-TCNQ) can be doped chemically with neutral phenazine (P). We investigated single crystals of a phase with composition Po.4(M2P)o.6TCNQ, i.e. (C 12HaN2)o.4(C 14HI4N2)o_.6(C 12H4N4) , C25.2 n15.6N6, M r = 402.44, triclinic, P1, a = 3.843 (3), b = 7.730(6), c = 16.028 (11) A, a -91.93 (6), fl = 93.56 (6), y = 94.57 (5) ° , V = 4 7 3 A 3 , Z = 1, d c = 1.41 Mg m -3. The structure was solved by direct methods and refined by least squares to R = 0.073 for 704 independent diffractometer data. The structure consists of segregated regular stacks of TCNQ and of dimethyl0567-7408/80/061435-06501.00 phenazine doped with 40% phenazine. Interplanar distances are 3.26 (1) A, in the TCNQ and 3.44 (1) A in the M2P stacks. The structure, the EPR data between 100 and 380 K and the electrical conductivity at room temperature are all very similar to those of N M P TCNQ.

The Structure of 5,10-Dihydro-5,10-diethylphenaziniumyl (E2P+)-2,2′-(2,5-cyclohexadiene-1,4-diylidene)-bispropanedinitrilate(TCNQ-) and its Difference to the Phenazine Doped Species E2P-P-(TCNQ)2 (P = Phenazine)

Phenazine free E2P-TCNQ, C28H22N6, Mr = 442.53 is monoclinic, P21/c, a = 10.875(3), b = 14.679(4), c = 14.526(2) Å, β = 90.90(2)°, V = 2321.9 Å3 , Z = 4, dc = 1.27 Mgm-3 , the compound doped with 50% phenazine, E2P-P-(TCNQ)2 C52H34N12, Mr = 826.93, is triclinic, P1̅, a = 7.739(3), b = 15.899(6), c = 17.037(7) Å, α = 83.44(3), β = 88.34(3), γ = 83.19(3)°, V = 2067.7 Å, Z = 2, dc= 1.33 Mgm-3. E2P-TCNQ was refined to R = 0.066 for 1880 reflections. It consists of planar TCNQ anions and bent E2P cations (dihedral angle 17.7° along the line N-N) arranged in regular mixed stacks along c. The structure of E2P-P-(TCNQ)2 could be solved principally, but did not refine well (R = 0.165 for 1206 reflections). Regular segregated stacks of the phenazine and the TCNQ moieties are formed, and along the cationic stack the E2P+ cations and the neutral phenazine molecules alternate.

TCNQ SALTS OF PLANAR METAL COMPLEX CATIONS: NOVEL MOLECULAR CONDUCTORS AND SEMICONDUCTORS.

Abstract The facile variation of positive charge of oxamide oxime metal complexes, caused by acid-base equilibrium, allows the growth of single crystals of their TCNQ salts. 1:1 salts consist of reqular segregated stacks of the components, with metallic room temperature behaviour of the Ni compound, the Pt compound being a semiconductor. Room temperature conductivities are of the order of 10 Siemens per cm. A 2:3 Pt complex TCNQ salt contains segregated acceptor stacks with half a negative charge per molecule. These stacks run perpendicular to mixed stacks -D-D-A-D-D-A-, with integral charges on donors D and acceptors A.

1:1-Salze des organischen Donors Tetra(methylthio)tetrathiafulvalen und Bis(maleonitriIdithiolato)-Komplexen: (TTM-TTF)+[Ni(mnt)2]- und (TTM-TTF)+[ Pt(mnt)2]- / 1:1 Salts of the Organic Donor Tetra(methylthio)tetrathiafulvalene and Bis(maleonitriledithiolate) Complexes: (TTM -TTF)+[Ni(mnt)2]- and (TTM -TTF)+[Pt(mnt)2]-

Abstract (TTM-TTF)+[Ni(mnt)2]- and (TTM-TTF)+ [Pt(mnt)2]- {TTM-TTF = Tetra(methylthio)tetra- thiafulvalene. mnt = maleonitriledithiolate} were obtained as products of the reactions of TTM-TTF with [Et4N][Ni(mnt)2] and [Et4N][Pt(mnt)2]. (TTM-TTF)+ [Ni(mnt)2]- is tridinic. P1, a = 7.650(2), b = 9.671(3). c = 9.846(4) Å. α = 103.47(3)°, β = 101.76(3)°, γ = 91.73(3)°, V = 6913 Å. Z = 1, dc = 1.75 g cm-3. For the isomorphous (TTM-TTF)+[Pt(mnt)2]- a = 7.749(2). b = 9.684(4). c = 9.883(3) Å, α = 103.31(2)°,β = 102.54(2)°, γ = 91.43(3)°, V = 702 Å3 Z= 1, dc = 2.04 g cm-3. The structures consist of mixed stacks of the organic radical cations and of bis(maleonitriledithiolato)metal(III) anions.

X-Ray Investigations of the Low-Temperature Phases of the Organic Metals α- and β-(BEDT-TTF)2I3

The structure of single crystals of the organic metals α- and β-(BEDT-TTF)2I3* was determined at 100 K, well below the phase transitions indicated by resistivity and thermopower measurements as well as by differential thermal analysis. In the α-phase no unusual change of the room temperature unit cell but a slight variation in the triiodide network and especially a more pronounced dimerization in one of the two donor stacks have been found. The β-phase develops a superstructure with a unit cell volume three times as large as that at room temperature and with pronounced distortions of the I3--ions.

The average structure of 5.10-Dihydro-5.10-Diethylphenazinium-Iodide (E2P·I1.6): A new linear chain Polyiodide compound

Abstract Upon oxidation of 5.10-dihydro-5.10-diethylphenazine (E2P) with iodine golden-green lustrous crystals of a compound with stoichiometry E2P.I1.6 were isolated. The compound crystallizes in the tetragonal space group D42 with a = 12.321(2) A and c = 5.330(2) A . The E2P and I form interpenetrating incommensurate sublattices along c, with an iodine repeat distance of 9.7 A. Static susceptibility measurements at room temperature give χg = + 0.994 × 10−6 g−1 × cm3. This corresponds to one unpaired electron spin per two formular units. Single-crystal EPR indicates that the paramagnetism is associated with weakly interacting E2P+ cation radicals. The 300K-d.c. conductivity of 3×10−2Ω−1cm−1 and activation energy of 0.17±0.02eV for single crystals is consequently associated with the polyiodide chains, and not with the E2P+ cation radicals.