Polyconjugated system

Radical Trapping. Figure 2 shows some of the reactions of aromatic amines that contribute to their activity as antioxidants and to their tendency to form highly colored polyconjugated systems. 

The rapid development of macromoiecular chemistry has recently brought to light a number of most interesting problems related to the synthesis of polymers with unusual properties. The chemistry of polyconjugated systems undoubtedly occupies a leading place among these problems. 

In the process of radical polymerization a monomolecular short stop of the kinetic chain arises from the delocalization of the unpaired electron along the conjugated chain and from the competition of the developing polyconjugated system with the monomer for the delivery of rr-electrons to the nf-orbitals of a transition metal catalyst in the ionic coordination process. Such a deactivation of the active center may also be due to an interaction with the conjugated bonds of systems which have already been formed. 

Krentsel, B. A., Khutareva, G. V. Khimiya polysopryazhennykh sistem (chemistry of polyconjugated systems). Moscow Khimiya, 1972... 

Davydov, B. E. and Krentsel, B. A. Progress in the Chemistry of Polyconjugated Systems. 

I Iapiot, P., L. D. Kispert et al. (2001). Single two-electron transfers vs successive one-electron transfers in polyconjugated systems illustrated by the electrochemical oxidation and reduction of carotenoids../. Am. Chem. Soc. 123 6669-6677. 

The results obtained are consistent with the existing views on the tendency of polyconjugated systems towards spontaneous stabilization upon thermal treatment heating makes the system more resistant to thermal degradation. TGA curves (Fig. 4.2) of the samples subjected to thermal treatment at 200 and 350°C are shifted to higher temperatures, with retention of the general pattern of weight loss. Thus, the carbon-rich structures were formed at relatively low temperatures. 

Apart from the class of push-pull molecules many other polyconjugated systems exhibit peculiar electronic properties which make them very attractive for technological applications. Most of these systems do not posses a permanent dipole moment and their mutual interactions are due only to London dispersion forces. Also in this case, however,... 

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