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Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/4642

Title: Electrophilic aromatic substitution in triphenylene discotics: synthesis of alkoxynitrotriphenylenes
Authors: Kumar, Sandeep
Manickam, M.
Balaguruswamy, V.S.K.
Schonherr, H.
Issue Date: 1999
Publisher: Taylor & Francis
Citation: Liquid Crystals, 1999, Vol,26, p1455-1466
Abstract: Functionalization of triphenylene-based discotic liquid crystals by direct nitration of hexaalkoxytriphenylene has very recently been reported to produce exclusively the mononitrohexaalkoxytriphenylene. We have found that nitration of such discotics is not restricted to only one ring of triphenylene, but all the three rings can be nitrated successively to produce mononitro-, dinitro- and trinitro-hexaalkoxytriphenylenes. All the mononitro derivatives show a very broadmesophase range.While the dinitrohexabutyloxytriphenylene is non-liquid crystalline, its higher homologues are room temperature liquid crystals. Photomicroscopic pictures of these liquid crystalline materials show classical textures of an ordered hexagonal columnar phase. X-ray di raction studies of two representative compounds, 4a and 4b, con rmed the above conclusions. None of the trinitro derivatives are liquid crystalline. Nitrotriphenylenes are valuable precursors to several other triphenylene derivatives like amino, acyl, alkylamino, diazo, etc. Mononitration of 2-hydroxy-3,6,7,10,11-pentaalkoxytriphenylenes gives the 1-nitro-2-hydroxy-3,6,7,10,11 pentaalkoxytriphenylenes. These double functionalized triphenylene derivatives are extremely important precursors as the functional group such as nitro, amino, azo, etc. can be utilized to modify the electronic nature of the core and at the same time the hydroxy functional groupmay be converted to a polymerizable group. Thus, processable oligomers and polymers can be synthesized.
Description: Restricted Access.
URI: http://hdl.handle.net/2289/4642
ISSN: 0267-8292
1366-5855 (Online)
Alternative Location: http://dx.doi.org/10.1080/026782999203788
Copyright: 1999 Taylor & Francis
Appears in Collections:Research Papers (SCM)

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