Carl W. Mayer

A new synthesis of unsymmetrical chalcogene substituted tetrachalcogene-fulvalenes.

Abstract The synthesis of pure, substituted, unsymmetrical tetrachalcogene fulvalenes from trimethyl-silyl-ethoxymethyl (SEM) protected TTF intermediates is described.

Bis-(trimethylsilyl-ethoxymethyl)-dichalcogenides and their application to tetrachalcogene-fulvalenes.

Abstract The synthesis of the bis (trimethylsilyl-ethoxymethyl)-disulfide and -diselenide (SEM-X 1 -X 1 -SEM) as well as their reaction with lithiated tetrachalcogene fulvalenes (TXF; X=S, Se) is described.

Transparent electrically conductive composite materials: Methods of preparation and their application

One possibility to obtain transparent, electrically conductive materials is the crystallization of conducting charge-transfer-complexes (CT-complexes) in a polymer matrix in the form of needle-or dendrite-like structures. With tetraselenotetracene chloride ((TSeT)2Cl), a radical cation salt, as electroconductive filler, we have access to a thermally stable, highly conductive material, with values of the bulk conductivity of the composite material up to 1 S/cm at a loading of the conductive complex below 1 %(w/w). The preparation of such composite structures as free standing (cast) films and in the form of very thin coated layers is presented and their electrical, optical and mechanical properties are discussed. In addition we show their potential use for display electrodes, transparent heating elements, and for antistatic applications.

Synthesis, superconductivity and X-ray data of the complex of the non symmetrical 4,5-d4-4′,5′-h4-BEDT-TTF with copper rhodanide

Abstract The specific synthesis of the non symmetrical donor 4,5-d 4 -4′5′-h 4 -Bis-(ethylenedithio)-TTF (d 4 ,h 4 -BEDT-TTF) and some preliminary structural data and physical properties of its κ-complex with Cu(SCN) 2 are described.

Electrical conduction and electronic structures of novel tetrathionaphthalene derivatives

The electrical conduction of pristine (undoped) and iodine doped vacuum deposited films of the novel donors, dibenzodithiotetra‐thionaphthalene and dibenzodithiotetraselenonaphthalene were measured. The electronic structures of these donor compounds were examined experimentally by ultraviolet photoelectron spectroscopy and theoretically by semiempirical MO calculations and compared with the corresponding data of tetrathiotetracene.

Structures and conductivities of a series of new charge transfer salts with tetraselenotetracene (TSeT): TSeT(PF6)0.5, TSeT(AsF6)0.5, TSeT(PF6)0.4, TSeT(AsF6)0.43

Abstract The new charge transfer salts TSeT(PF6)0.5, TSeT(PF6)0.4, TSeT(AsF6)0.5 and TSeT(AsF6)0.43 have been prepared. Their crystal structures and semiconducting electrical conductivities are reported and discussed in the context of the search for superconducting materials analogous to TMTSeF(PF6)0.5.

Transparent electrically conductive composites by in situ crystallization of (TSeT)2Cl in a polymer matrix

A new chemical pathway was found which offers access to the thermostable, highly conductive tetraselenotetracene chloride radical cation salt (TSeT)2Cl. This pathway allows the in-situ crystallization of (TSeT)2Cl in a vitrifying polymer matrix. So highly conductive films (σ= 1–5 Scm-1) with networks of (TSeT)2Cl crystallites of a 1: 1000 aspect ratio could be prepared at a fairly low percolation threshold of 0.4 – 1.6 % w/w. These films show metallic conductivity behavior in the 60 – 400 K range.

3,4,9,10 - Tetrathioperylene - I1.28, a new highly conducting, incommensurate organic charge transfer salt

Abstract We report here the preparation of TTP - I1.28 (TTP = 3,4,9,10 - Tetrathioperylene), the crystal structures of TTP and its complex TTP - I1.28 and their electrical conductivities. The crystal structure of TTP consists of two inequivalent types of segregated stacks with intermolecular planar spacings of 3.43 A, and 3.47 A. The crystal structure of TTP - I1.28 consists of two incommensurate sublattices. The TTP sublattice is built up by segregated stacks of TTP molecules with interplanar spacing of 3.25 A. The iodine sublattice consists of columns formed mainly by I3 units. The electrical conductivity is very weakly metallic at room temperature and turns to a semiconducting behavior at 220 K with an activation energy of 15 meV.

New electroactive 2-n-octyloxy-5,6,11,12- tetrathiotetracene dodecylsulfate cation radical salt: Formation at the air-water interface and characteristic properties of Langmuir-Blodgett films

Abstract The formation and characteristic properties of the new electroactive 2-n-octyloxy-5,6,11,12-tetrathiotetracene dodecylsulfate cation radical salt 1 are described. The salt is prepared in monomolecular layers at the air-water interface according to the following steps: (a) neutral donor molecules of 2-n-octyloxy-5,6,11,12-tetrathiotetracene 2 are spread on an aqueous sodium dodecylsulfate solution, (b) the monolayer of 2 thus prepared is gradually oxidized by air under formation of cation radicals, while (c) the dodecylsulfate ions 3 present in the subphase are inserted in the monolayer as counterions of the cation radicals. This insertion is accompanied by an expansion of the monolayer by about 70% of the original area. The oxidized monolayers can be easily deposited on different substrates by the Langmuir-Blodgett (LB) technique. Characterization of the LB films by various spectroscopic methods such as UV-visible, IR and ESR spectroscopies indicates that the films consist exclusively of the cation radical salt 1. Electron spin resonance spectroscopy studies suggest that the tetrathiotetracene molecular plane is oriented perpendicular to the substrate plane. It is demonstrated by conductivity measurements and cyclic voltammetry that the LB films are poorly conducting but can be reversibly oxidized and reduced electrochemically.