LPPP, chemical structure

In Figure 8-1 we show the chemical structure of m-LPPP. The increase in conjugation and the reduction of geometrical defects was the main motivation to incorporate a poly(/ -phenylene)(PPP) backbone into a ladder polymer structure [21]. Due to the side groups attached to the PPP main chain excellent solubility in nonpolar solvents is achieved. This is the prerequisite for producing polymer films of high optical quality. A detailed presentation of the synthesis, sample preparation,... 

FIGURE 1.38 Chemical structure of m-LPPP (left) and RSI9 (right). 

If suppression of the aggregate emission in this first example was based on a purely physical principle, chemical modification of the LPPP 15 structure for the same aim is also possible. Thus, one option is the introduction of additional substituents into the LPPP skeleton. Thus, the introduction of an additional methyl group to the methylene bridge in LPPP (addition of LiCH3 in place of reduction of the keto groups) leads to ladder polymers 12 whose solid state PL spectra show only very weak aggregate emissions the solution- and solid state PL spectra are almost identical (Fig. 5 [30]). 

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