| Abstract
| - An iterative synthesis of cross-conjugated iso-polydiacetylenes (iso-PDAs) is reported based on threefundamental building blocks: vinyl triflates 8, 9, and 25. An efficient sequence of palladium-catalyzed cross-coupling reactions of vinyl triflates and terminal alkynes has been employed toextend the chain length of these oligomers. The longest member of the series, nonamer 19, spans3.4 nm from Si to Si atom. The stability and solubility of the conjugated oligomers have beenevaluated as a function of pendant substitution. Assessment of solid-state structural propertieswas achieved via X-ray crystallographic analyses of monomer 12 and trimer 14. The electroniccharacteristics of the monodisperse oligomers have been fully analyzed by UV−vis spectroscopy insolution and as thin films, and these studies suggest that π-electron communication is presentalong the enyne framework, but quickly reaches saturation by the stage of nonamer 19.
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