Poly(triacetylene)s: A new class of linearly pi-conjugated oligomers and polymers with an all-carbon backbone

Linearly pi -conjugated polymers are intensively investigated in both acade mia and industry for a diversity of advanced materials applications. Polyac etylenes (PAs) and poly(diacetylene)s (PDAs) were among the earliest invest igated linearly pi -conjugated polymers possessing an all-carbon backbone. They actually represent the first members in an entire progression of linea r all-carbon polymers which starts with polyacetylene and ultimately extend s to carbyne. Here, we describe the discovery and systematic investigation of poly(triacetylene)s (PTAs), the third class of compounds in this progres sion. We report both the preparation of longer-chain polydisperse PTA polym ers as well as the synthesis, characterization, and physical study of monod isperse oligomers with record lengths extending up to 18 nm. We show how mo lecular properties evolve into the saturation range with increasing oligome ric length and report several direct determinations of the effective conjug ation length (ECL), i.e. the oligomeric length at which saturation of molec ular properties occurs. Finally, we present a new class of hybrid oligomers and polymers, with a diversity of chromophores inserted as functional spac ers into the PTA backbone for further enhancement of optoelectronic propert ies.