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Convergent Synthesis of Columnar Twins and Tetramers from Triphenylene Building Blocks – The First Example of a Columnar Spiro‐Twin
Author(s) -
Schulte Jörg L.,
Laschat Sabine,
Vill Volkmar,
Nishikawa Etsushi,
Finkelmann Heino,
Nimtz Manfred
Publication year - 1998
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199811)1998:11<2499::aid-ejoc2499>3.0.co;2-l
Subject(s) - triphenylene , chemistry , columnar phase , crystallography , stereochemistry , molecule , organic chemistry , liquid crystalline , phase (matter)
The novel spiro‐twins 3a – f were prepared in three steps by one‐pot oxidative coupling of guaiacol ( 9 ) and 1,2‐dialkoxybenzenes 10a – f , followed by demethylation of the triphenylene 11 and subsequent etherification with the tetrabromide 6 . A related strategy gave the tetramers 7a – f in two steps. Whereas derivatives 3a , b and 7a , b with pentyloxy and hexyloxy chains showed isotropic melting behavior, compounds 3c – f and 7c – f with longer alkyl chains displayed columnar mesophases. DSC, polarizing microscopy, X‐ray diffraction and molecular modeling studies were used to further characterize the type of mesophase. For the spiro‐twin 3 either a rectangular or a hexagonal columnar phase were conceivable. In case of 7f a hexagonal columnar mesophase was assigned.