Through bond and through space interactions in oligo–alkoxythiophenes: A spectroscopic study

Abstract

The aim of this work is to understand the molecular structural properties which may justify the great observed stability of doped alkoxy polythiophenes. Infrared frequency and intensity spectroscopy and Raman spectroscopy are used as probes. Suitably synthesized oligomers with increasing chain length and preassigned chemical structure have been studied together with several model molecules. The existence of through-space and through-bond S- - -O interactions has been revealed. The extent of the topologically dependent perturbation induced by the charge injection by the oxygen atoms is detected and measured. The inter- and intraring delocalizations have been monitored by the observation of the softening of the strongly Raman active ‘‘amplitude mode’’ and by the red shift of the electronic spectra. The conformation of the side chains is trans planar in the solid state and collapses in a liquidlike premelting state before the melting of the crystal.

Influence of the Supramolecular Organization on the Magnetic Properties of Poly(3-alkylthiophene)s in Their Neutral State

“…This suggests a possible relationship between the fraction of planar polymer chains, found by UV–vis spectroscopy and/or DSC and the saturation magnetization (Figure ). In this perspective, our hypothesis explains the high number of Bohr magnetons observed for HT-P3AOT in which S–O interactions induce a planar polymer conformation, which is for example also reflected in its large λ max value. In summary, the high number of Bohr magnetons is related to the planarization of the polymer backbone.…”

Conformational Behavior of Conjugated Polymers With Oligo(phenylene vinylene) Side Chains

“…Concerning the connecting aromatic group, both 3,3′‐dimethoxybithiophene and thienothiophene were considered. Due to the presence of S—O interactions, the bithiophene adopts a planar conformation 27. As a consequence, both groups connect the phenylene groups in a linear way, so no additional kinks are introduced.…”

Doping-Induced Structural Changes of Conducting Polyalkoxythiophene on the Chemically Modified Gold Surface: An in Situ Surface Enhanced Resonance Raman Spectroscopic Study

“…The complete reliable assignments of the vibrational spectra of neutral polyalkoxythiophenes have not been obtained yet, although a multitude of normal coordinate calculations and experimental infrared and Raman measurements for neutral thiophene (T), , PT, − polyalkylthiophenes, − and polyalkoxythiophenes ,− has been carried out.…”

“…However, the main drawback of PT derivatives is the instability of their conductive form. Poly-3-(3‘-thienyloxy)-1-propanesulfonate (P3TOPS) is one example of semiconducting conjugated polyelectrolyte − where these disadvantages seemingly obviated. Indeed, sulfonic acid substitution in the P3TOPS side chain increases water solubility and gives the polymer a self-doping character…”