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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/12385

Title: Synthesis, Structure, and Nonlinear Optical Properties of Cross-Conjugated Perphenylated iso-Polydiacetylenes
Authors: Zhao, Yuming
Slepkov, Aaron D.
Akoto, Clement Osei
McDonald, Robert
Hegmann, Frank A.
et. al
Keywords: cross conjugation
enynes
foldamers
nonlinear optics
optical Kerr effect
polydiacetylenes
Issue Date: Jan-2005
Publisher: WILEY‐VCH Verlag
Citation: Chem. Eur. J. 2005, 11, 321 – 329 www.chemeurj.org J 2005 Wiley-VCH Verlag GmbH & Co.KGaA, Weinheim
Abstract: Monodisperse, cross-conjugated perphenylated iso-polydiacetylene (iso-PDA) oligomers, ranging from monomer 15 to pentadecamer 25, have been synthesized by using a palladium-catalyzed cross-coupling protocol. Structural characteristics elucidated by X-ray crystallographic analysis demonstrate a non-planar backbone conformation for the oligomers due to the steric interactions between alkylidene phenyl groups.The electronic absorption spectra of the oligomers show a slight red-shift of the maximum absorption wavelength as the chain length increases from dimer 17 b to pentadecamer 25, a trend that has saturated by the stage of nonamer 22.Fluorescence spectroscopy confirms that the pendent phenyl groups present on the oligomer framework enhance emission, and the relative emission intensity consistently increases as a function of chain length n.The molecular third-order nonlinearities, g, for this oligomer series have been measured via differential optical Kerr effect (DOKE) detection and show a superlinear increase as a function of the oligomer chain length n. Molecular modeling and spectroscopic studies suggest that iso-PDA oligomers (n>7) adopt a coiled, helical conformation in solution.
Description: An article published by WILEY‐VCH Verlag and also available at DOI: 10.1002/chem.200400822
URI: http://hdl.handle.net/123456789/12385
Appears in Collections:College of Science

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