Oligothiophenes electronic structure

Bauerle P, Segelbacher U, Maier A, Mehring M (1993) Electronic-structure of monomeric and dimeric cation radicals in end-capped oligothiophenes. J Am Chem Soc 115 10217... 

Some heterocyclic aryl halides are very likely to dehalogenate. In the case of oligothiophenes, the halogenation was highly dependent on small changes of the electronic structure of the aryl halide [87]. The side reaction was suppressed by adjusting the basicity of the reaction mixture. In other cases an alternative StiUe protocol was found [88]. 

The electronic structure of oligothiophenes is characterized by UPS and MO calculations for the occupied states and by a variety of optical techniques for the transition between occupied and unoccupied levels. Because of the vast number of papers on optical measurements, only a selection demonstrating the most important features can be presented here. 

J. Casado, T. M. Pappenfus, K. R. Mann, V. HernSndez and J. T. Ldpez Navarrete, Exploration of the electronic structure of dendiimer-like acetylene-bridged oligothiophenes by correlating Raman spectroscopy, electrochemistry and theory, J. Chem. Phys., 120, 11874-11881 (2004). 

Figure 8,6 Monomer molecular orbital contour plots of the HOMO and LUMO orbitals of FTF, TFTFT and TFT. Reprinted with permission from S. E. Koh, B. Delley, J. E. Medvedeva, A. Facchetti, A. J. Freeman, T. J. Marks and M. A. Ratner, Quantum chemical analysis of electronic structure and n- and p-type charge transport in perfluoroarene-modified oligothiophene semiconductors, J. Phys. Chem. B, 110, 24361 24370 (2006), Copyright 2006 American Chemical Society...

A. Raya, M. A. Mora, Theoretical study of perfluorinated oligothiophenes electronic and structural properties. Polymer, 45, 6391-6397 (2004). 

Drawn polythiophene films show enhanced conductivity along the drawn direction of the film [50,51,80]. This means that one-dimensional carrier transport along the polymer chain will be the prevailing electronic process. This feature should be probed by anisotropic (or dichroic) spectroscopic measurements. Meanwhile, the spectral profiles of the oligothiophenes taken in the solid state differ significantly from those in dilute solution (see Section 2.3). This implies that the electronic processes in the solid state are considerably different in the nature from those in solution. In this section we describe the spectroscopic characteristics of the polythiophenes and oligothiophenes in both the neutral and doped forms in the solid state and correlate these characteristics with electronic structure and properties. 

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