G. Klar

Structure and electrical conductivity of TCNQ-2,3,7,8-tetramethoxychalcogenanthrene complexes

Abstract Charge-transfer complexes formed by reaction of 2,3,7,8-tetramethoxychalcogenanthrenes(5,10-dichalcogenacyclo-diveratrylenes, ‘Vn 2 E 2 ’) with 7,7,8,8-tetracyanoquinodimethane (TCNQ) are prepared and their structures determined. Spin concentration, mobilities and gap energies of the polycrystalline samples are evaluated from e.s.r. intensities and electrical conductivity measurements. The influence of the different chalcogen atoms on physical properties is discussed.

Elementorganische Verbindungen mit o-Phenylenresten, IV [1]Synthese von 2.3.7.8.12.13-Hexamethoxytribenzo[b.e.h] [1.4.7]- trithiacyclononatrien / Organometalloidal Compounds with o-Phenylene Substituents, IV [1]Synthesis of 2,3,7,8,12,13 - Hexamethoxytribenzo [b,e,h] [1,4,7] trithiaonin

Abstract The synthesis of the title compund, starting from 1,2-dimethoxybenzene, is described.

Structure, electrical conductivity and dielectric relaxation of the phenothiazine-tetracyanoethene 1:1 complex

Abstract Phenothiazine (PTZ) as a donor and tetracyanoethene (TCNE) as an acceptor form the dark blue charge-transfer complex PTZ-TCNE. In the solid state stacks are found in which the donor (D) and acceptor (A) molecules alternate according to the sequence –D—A– –D—A– –D—A–. Within the stacks the donor and acceptor molecules are arranged coplanarly to each other in such a way that an optimum overlap of the corresponding HOMOs and LUMOs is guaranteed, as is shown by MNDO calculations. PTZ-TCNE is a semiconductor with a gap energy of E g = 1.69 eV and a pre-exponential factor of σ o = 575 S cm −1 . Its dielectric relaxation is of the non-Debye type (non-symmetrical Cole-Cole plot, described by a Havriliak-Negami equation) showing a temperature dependence characterized by an Erying equation with an activation enthalpy of ΔH ν = 0.99 eV and entropy ΔS ν ≈ 10 −3 eV K −1 . The temperature dependence was also analysed in terms of an Arrhenius equation leading to E a = 1.05 eV.

CHALKOGENOLAT-IONEN UND IHRE DERIVATE, XVIII.1 CYCLISCHE DIARYLDISULFIDE AUS DISCHWEFELDICHLORID UND AKTIVIERTEN AROMATEN

Abstract Diaryldisulfides are formed in polar solvents by reaction of disulfurdichloride with aromatic ompounds activated by alkoxy substituents. Starting from 1,2-dialkoxybenzenes or 2,3-dialkoxynaphthalenes or from suitably substituted biphenyls cyclic bis or monodisulfides, the dibenzo or dinaphthotetrathiocines 2 and 3 and the dibenzo-1,2-dithiines 4–6, are formed in fairly good yields. Aus Aromaten, die durch Alkoxysubstituenten aktiviert sind, bilden sich durch Einwirkung von Dischwefeldichlorid in polaren Solventien Diaryldisulfide. 1,2-Dialkoxybenzole und 2,3-Dialkoxynaphthaline oder geeignet substituierte Biphenyle liefern cyclische Bis- oder Monodisulfide, wie die Dibenzo- oder Dinaphthotetrathiocine 2 und 3 und die Dibenzo-1,2-dithiine 4–6 in relativ guten Ausbeuten.

Crystal and molecule structure of 1,3,5,7-tetraarsa-2,4,6,8-tetraoxaadamantane

Abstract The colourless crystals of the title compound are monoclinic, a = 679.0(10), b = 1003.0(9), c = 1191.4(8) pm, β = 105.14(8)°, space group P2 1 /c. A three dimensional X-ray analysis of the structure was made with counter data (1903 unique reflections with | F o | > 3σ). The structure was determined by direct methods and refined anistropically by full matrix least squares methods to a conventional unweighted R of 0.059. The structure consist of discrete molecules As 4 O 4 (CH 2 ) 2 which can be described as penetrating distorted As 4 -tetrahedra and trans -O 4 C 2 -octahedra. The mean bond lengths and angles are: AsO = 179.5, AsC = 196.2 pm, OAsO = 101.8, CAsO = 99.3, AsOAs = 129.0, AsCAs = 119.4°.

Structure and dielectric relaxation of 2,3,7,8-tetramethoxychalcogenanthrene-TCNQ complexes

Abstract 2,3,7,8-Tetramethoxychalcogenanthrenes (5,10-dichalcogena- cyclo -diveratrylenes, Vn 2 EE′) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) form charge-transfer (CT) complexes of composition Vn 2 EE′·TCNQ (E = E′ = S, Se; E = S, E′ = Se, Te). The structure of the hitherto unknown compound Vn 2 STe·TCNQ is described. The dielectric relaxation of the whole series of CT complexes is determined and the results are correlated with the structural data.

ORGANOMETALLOIDAL COMPOUNDS WITH O-PHENYLENESUBSTITUENTS, PART XXVII.1 SYNTHESIS, CHARACTERIZATION AND STRUCTURE DETERMINATION OF 2,3,7,8-TETRAKIS(METHYLTHIO)-AND 2,3;7,8-BIS(ETHYLENEDITHIO)THIANTHRENE

Abstract A generally applicable synthesis via the sequence thiophenol (3), 1,2-bis(alkylthio)benzene (6), 1-bromo-3,4-bis(alkylthio)benzene (7), bis[3,4-bis(alkylthio)phenyl]sulfide (8), bis[2-bromo-4,5-bis(alkylthio)-phenyl]sulfide (9), 2,3,7,8-tetrakis(alkylthio)thianthrene (2) has been worked out for the title compounds. Their 1H-NMR, MS and CV data are given, the results of the crystal structure determinations as well.

Structure, electrical conductivity and dielectric relaxation of a 1,2-dimethoxybenzene-tetracyanoethene 1:1 complex

Abstract 1,2-Dimethoxybenzene (Ver) as a donor and tetracyanoethene (TCNE) as an acceptor from the dark blue charge-transfer complex Ver·TCNE. In the crystal stacks, in which the donor (D) and acceptor (A) molecules alternate according to the sequence …DAD…A…DAD…A…, centro-symmetric DAD units can be distinguished. In these units the molecules are arranged in such a way that an optimum overlap of the corresponding HOMOs and LUMOs is guaranteed, as is shown by MNDO and HAM 3 calculations. Ver·TCNE is a semiconductor with a gap energy of Eg = 0.85 eV and a pre-exponential factor of σo = 0.91 S/cm. The temperature dependence of dielectric relaxation is characterized by an Eyring equation and gives an activation enthalpy of ΔH ‡ = 0.76 eV and entropy ΔS ‡ = 0.95 × 10 −4 eV/K .

ELEMENTORGANISCHE VERBINDUNGEN MIT o-PHENYLENRESTEN, XII1 2,3,7,8-TETRAMETHOXYDIBENZO-1,4-THIASELENIN UND -THIATELLURIN

Abstract The syntheses of the title compounds are described, both starting from bis (3,4-dimethoxyphenyl)sulfide (7). The thiaselenin 4 is formed by melting 7 with selenium dioxide. Mercuration of 7 followed by reaction with tellurium tetrachloride leads via its dichloro derivative 10 to the thiatellurin 5. The 1H-NMR and MS data of compounds 4 and 5 are reported.

SELFSTACKING SYSTEMS, PART 6.1 HOST LATTICE FUNCTION OF 2,3,8,9-TETRAMETHOXYDIBENZO[c,e][1,2]-DICHALCOGENINS IN THEIR ELECTRICALLY CONDUCTING IODINE COMPLEXES

Abstract The structures of 2,3,8,9-tetramethoxydibenzo[c,e][1,2]dithiin (o-S2, 1) and -diselenin (o-Sc2, 3) have been determined hy single-crystal X-ray diffraction methods. Both compounds have a columnar structure in which the orientation of the molecules alternates with respect to their dichalcogeno bridges. The same kind of slacks had been found before in the electrically conducting iodine complex [o-S2]1 1.16 (2) with channels parallel to the stacks in which chains of disordered polyiodide ions are intercalated, i,e. the host lattice of 2 is performed in 1. o-Se2-(3) also forms an iodine complex of composition [o-Se2]1, (x = 1.5–2.5) (4) which is, however, thermally unstable loosing iodine already at room temperature. For reasons of comparison the X-ray structure of 3,3′,4,4′-tetramethoxybiphenyl (5) has also been determined.