Jian He - ortho-Phenylenes: Unusual Conjugated Oligomers with a Surprisingly Long Effective Conjugation Length

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      Publication Details (including relevant citation   information):

      J. Am. Chem. Soc., 132 (39), 13848–13857 (2010) DOI:   10.1021/ja106050s Publication Date (Web): September 10, 2010

      Abstract:

      ortho-Phenylenes represent a fundamental but relatively   unexplored class of conjugated molecular architecture. We have   developed a robust synthetic approach to monodisperse   o-phenylene oligomers which we have demonstrated by   synthesizing a homologous series up to the dodecamer. The   o-phenylenes exhibit complex conformational behavior but   are biased toward a specific 2-fold-symmetric conformation which   we believe corresponds to a stacked helix. Surprisingly, the   series exhibits long-range delocalization, as measured by   bathochromic shifts in UV/vis spectra. Although the overall   magnitude of the shifts is modest (but comparable to some other   classes of conjugated materials), the effective conjugation   length of the series is approximately eight repeat units. The   oligomers also exhibit an unusual hypsochromic shift in their   fluorescence spectra with increasing length. The origin of these   trends is discussed in the context of conformational analysis and   DFT calculations of the frontier molecular orbitals for the   series.

      Address (URL): http://pubs.acs.org/doi/abs/10.1021/ja106050s?journalCode=jacsat&quickLinkVolume =132&quickLinkPage=13848&volume=132