A new series of pure and highly soluble oligodiacetylenes (ODAs) was synthesized in high yield and on a multi-milligram scale by a sequence of Sonogashira reactions with a strongly reduced level of homocoupling. The lambda max and epsilon max of these ODAs show an increase with both chain elongation and solvent polarity. A plot of lambda max absorption versus 1/CL (CL=conjugation length) was shown to be linear.
View Article and Find Full Text PDFThe excited-state dynamics of an oligomer of polydiacetylene, 2,2,17,17-tetramethyloctadeca-5,9,13-trien-3,7,11,15-tetrayne, dissolved in n-hexane have been studied by femtosecond fluorescence upconversion and polarized transient absorption experiments under one- and two-photon excitation conditions. Spectroscopically monitoring the population relaxation in the excited states in real time results in a distinct time separation of the dynamics. It has been concluded that the observed dynamics can be fully accounted for on the basis of the two lower excited states of the target molecule.
View Article and Find Full Text PDFThe photophysical properties of a series of monomeric, dimeric and trimeric oligodiacetylenes (ODAs; oligoenynes) bearing trimethylsilyl, t-butyl and n-octyl end-capping substituents were studied in solution and in a polymer film. Emission studies show a significant emission of oligodiacetylenes in solution, which increased with increased conjugation. This is remarkable given the near absence of fluorescence in oligoenes of similar length (e.
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