Gerhard Heywang

Electrochemical and spectroscopic characterization of polyalkylenedioxythiophenes

Abstract The electrosynthesis of polyalkylenedioxythiophenes is described, starting with the anodic oxidation of 3,4-ethylenedioxythiophene ( 1 ) or 3,4-trimethylenedioxythiophene ( 2 ). The resulting polymers are extraordinarily stable during charging and discharging. Owing to a narrow band gap, the first long-wavelength absorption in the doped state appears above 900 nm.

Technical applications for conductive polymers

Abstract Whereas organic conductors were, for a long time, simply curiosities found in the laboratory, the first technical applications for them are now beginning to emerge. Films coated with polypyrrole meet the demands made on antistatic packaging materials. Considerably better properties permitting long term use under adverse ambient conditions can be obtained by using 3,4-polyalkylenedioxythiophenes.

Crystal structure of 1,4,5,8-naphthalene-tetracarboxylic- dianhydride (NTDA)

The crystal structure of the title compound has been determined at room temperature. The crystals are monoclinic, space group P2i/c, Ζ = 2, with a = 7.867(2), b = 5.305(1), c = 12.574(2) Ä and β = 72.73(2)°. The structure was refined to R = 0.042 for 589 observed reflections. The molecule is on an inversion center. The agreement among chemical equivalent bond lengths is generally very good, thus confirming the short carbonyl distance (1.185 Ä). The crystal is built of stacks of only partially overlapping NTDA molecules along b. Introduction 1,4,5,8-Naphthalene-tetracarboxylic-dianhydride (NTDA), C 1 4 H 4 0 6 (1), has been reported to form radical-anion salts with numerous organic cations (Heywang et al., 1989). To gain a better understanding of crystal structure determinations of these complexes, reasonably accurate distance and angle information for the NTDA molecule will be needed. The packing mode of the molecule without cations is also of interest. 148 Liborius Born and Gerhard Heywang Table 1. Positional parameters and their estimated standard deviations.

New radical cation salts of substituted pyrenes

Abstract Pyrenes with alkylthio substituents represent a new class of relatively cheap donor compounds which can be reacted to very stable radical cation salts with high conductivity (up to 677 S/cm).