Poly ladder-type pentaphenylene s

The polymer 190 produces blue PL and EL with an emission maximiun at 445 nm and a very small Stokes shift, and so closes the gap in emission colour between PIFs and LPPPs. The optical properties are very similar to those of 

LPPP 3, but the blue emission is much more stable. Polymer 190 also has a remarkably large persistence length of 25 nm [284], indicating a highly rigid structure. 

---

Scheme 45 Synthesis of poly(ladder-type pentaphenylene)s...

PFs, PlFs, and poly(ladder-type pentaphenylene)s have methine bridges, and so are structurally related to LPPP 3. Stepladder polymers have also been prepared with other types of bridges. 

---