Conductive conjugated systems, electronic

Electronic Structure of Conductive Conjugated Systems and Their Physicochemical Properties... 

Rotations around torsional barriers induce changes in chain conformation. For conjugated systems like polydiacetylenes, flow-induced changes in chain conformation can have a profound influence on the photon absorption and electronic conductivity properties of the material [73]. Flow-induced changes in molecular conformation form the basis for several technically important processes, the best known examples are the production of oriented fibers by gel spinning [74], the compatibility enhancement [75] and the shear-induced modification of polymer morphology [76]. 

The low conductance of the Ji-conjugated system is due to the nodes at the imide nitrogen positions. Several additional trends have been observed. The conductance of pyridine-terminated PBI derivatives (P-PBI) is typically a factor of 2 larger than the thiol-terminated ones (T-PBI). Although the Au-S bond provides a stronger electronic coupling than the Au-N bond, the T-PBI has two extra methylene... 

In systems in which the donor and acceptor centers are in direct contact with each other or connected by a conducting bridge (conjugated bonds), electron transfer rates are very fast (kET = 10"13 -10 12 s 1). The transition occurs markedly slower when the donor-acceptor mutual orientation is not favorable for positive orbital overlap and, therefore, the electron coupling V is small. 

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