Poly acenes

In 1993, Scherf and Chmil described the first synthesis of a ladder-type poly(pflra-phenylene-czs-vinylene) (116) [138]. On the one hand, ladder polymer 116 represents, a planar poly(phenylene) containing additional vinylene bridges on the other hand, it is a poly(phenylenevinylene) with aryl-aryl linkages in the polymeric main chain. The target macromolecules, as fully aromatic ladder polymers, are composed of all-carbon six-membered rings in the double-stranded main chain (an example of angularly annelated poly(acene)s). 

The method of photoselection to study the polarization of triplet-triplet transitions has been applied by El-Sayed and Pavlopoulos 6) to several poly-acenes. Let us discuss some of the results obtained on napthalene, where the -axishas been chosen along the long molecular axis and they-axis along the short one. The first very weak Si- - 5o absorption band x-polarized) is... 

When cr0 is plotted vs. AE, a linear relationship is obtained (Figure 3). Poly-acenes show a similar linear relationship, which may be parallel to that of the isonitrile complexes investigated and which is displaced toward lower values of o-o- A comparison between the isonitrile complexes and polyacenes demonstrates most clearly the wide ranges of activation energies, AE, and of the constant, o-o, which may be achieved merely in one series of coordination complexes as compared to polyacenes. 

Htickel spectrum is of the form [110] e k) = v/2 [1 -I--I- 1 -rj ) cos rfe], where 0 < fe < 1. This case is intractable analytically, but numerical computations are easily performed, and the results are given in Table 6.7 (the first two systems in the table). Another interesting example is the linear poly acene (the third system in Table 6.7), for... 

Figure 18 Molecular structure of poly(acene quinones) used in Figure S.

Fig. 1.3 Structure of poly(acene-quinone radical) polymers.

For complete success in the synthesis of poly(/ )-acenes, careful optimization of the structure of the starting materials and of the reaction conditions is necessary. 

As depicted in Figure 2A, the Bt, transition of poly-acene chromophores is ideally suitable for observing exciton coupled CD. See below for a description of the fluorescent 2-anthroate chromophore. 

The reason they are called "ladder" polymers is because they may be considered derivatives of poly(acene), whose structure (Fig. 14-23) is characterized by two linear sideframes with interconnecting "rung" bonds, very much like that of a ladder. For our purposes, they do qualify as CPs, since they are possess a 7r-conjugated polymeric structure, and can indeed also be doped for greatly increased conductivity. The interest in these polymers has been due to their greater thermal and oxidative stability as compared to more conventional CPs, their facile processibility in their... 

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