Phenyl-substituted ladder-type

Very little Information, however, is available concerning the preparation of ladder type poly(siIsesquioxanes) in which phenyl group is substituted by any other groups. 

All partially bridged PPPs have been synthesized by the Yamamoto-type homocoupling protocol using preformed building blocks (e.g., dialkylfluorene, tetraalkylmdenofluorene, and octasubstituted penta-phenyl blocks). The fuUy bridged ladder polymer MeLPPP has been synthesized by the already outlined cyclization protocol of suitably substituted, single-stranded PPP precursors (Scheme 5.2). 

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