Jonas Hellberg

A convenient and improved synthesis of dithieno[3,2-b:2′,3′-d]thiophene

Abstract An improved synthesis of dithieno[3,2- b :2′,3′- d ]thiophene 1 is presented. By starting from 2,3-dibromothiophene 2 the total yield was improved from 35 to 58%. We also describe a more convenient synthesis of one of the reagents, benzenesulfonic acid thioanhydride 3 .

Conducting polymers from dimethyl-2,2′-bithiophenes

Electrochemical oxidation of symmetrical dimethylbithiophenes with free α-positions yields electroactive polymers with excellent cycling ability.

A general procedure for the synthesis of methylthio-, methylseleno- and methyltelluro-substituted aromatic compounds

Abstract A one-pot procedure is described which allows the facile introduction of one or two methylchalcogeno groups into a variety of monobromo or dibromo aromatics. The bromo compounds were converted to their corresponding lithio derivatives by treatment with t-butyllithium in tetrahydrofuran at −78°C, and these derivatives were then treated, at ambient temperature with elemental sulfur, selenium, or tellurium. The resulting lithium thiolates, selenolates and tellurolates were finally methylated with methyl iodide to afford good yields (typically 50–80%) of the various methylchalcogeno-substituted aromatic compounds. The procedure could not be used for the synthesis of ortho -disubstituted compounds, or for the simultaneous introduction of three methylchalcogeno groups.

Fabrication and characterization of schottky gate poly(3-alkylthiophene) planar field-effect transistors

Abstract In this paper fabrication and characterization of Schottky gate planar field-effect transistors using poly(3-alkylthiophene) as an active semiconductor region are reported. This is the first time that planar MESFET transistors utilizing a polymer semiconductor have been fabricated and measured. Aluminum metal is used for the rectifying contact and two gold electrodes are constructed as source and drain. From the MESFET characteristic the channel carrier mobility is evaluated as 10 −5 cm 2 V −1 s −s , which is one order of magnitude larger than a MOSFET utilizing the same polymer.

New monomers for polythiophenes

Two series of chalcogen substituted thiophene monomers have been synthesised; 3-(4-alkylchalcogenophenyl)thiophenes 1a-c and 3-(4-alkylphenylchalcogeno)thiophenes 2a-d. Polymerisations of examples of these with iron(III)chloride gave regiorandom polymers. Light-emitting diodes with low efficiency could be fabricated from poly-1a and poly-1b.

New alkoxylated dibenzo[1,4]dichalcogenines as donors for low-dimensional materials: electrochemistry and cation-radical salts

The synthesis of new alkoxylated dibenzo[1,4]dichalcogenines (3a–c), (3e–f), (3h), (4a–h), and (5a) is presented. The first cyclovoltammetric half-wave potentials of these compounds range from 0.62 to 1.06 V vs. standard calomel electrode (s.c.e.). Cation radical salts of several different stoicheiometries have been prepared from the new donors.

Bithiophenes as starting monomers for polythiophene syntheses

Abstract Bithiophenes, when used as starting material for polythiophene synthesis, offer advantages over corresponding thiophenes. Polymerization proceeds at lower oxidation potentials and lower monomer concentration and gives polymers with higher yield and better regularity as shown by cyclic voltammetry and 1H NMR spectroscopy.

Synthesis of annulated dioxins and their use as donors for cation radical salts

Abstract The synthesis of a series of new alkoxylated annulated dioxins is described together with their cyclovoltammetric behaviour.

Ethylenedithio end-capped oligothiophenes (bEDTnT); Dimer, trimer and tetramer

Two new ethylenedithio substituted thiophenes (I; R = H, Br) have been synthesized. Starting from I (R = Br), oligomers II (n = 0, 1, 2) were synthesized. Their cyclic voltammetric behavior and ele ...

A New Cation Radical Salt: (bMDODBF)2AsF6

Abstract The AsF− 6 cation radical salt of 2,3,6,7-bis-methylene-dioxydibenzofuran has been synthesized. Its structural, electrical and ESR properties are presented.