Lateral extension induces columnar mesomorphism in crucifix shaped quinoxalinophenanthrophenazines. Issue 2 (14th January 2015)

• Record Type: Journal Article
• Authors: El-Ballouli, Ala'a O.; Kayal, Himadri; Shuai, Chen; Zeidan, Tarek A.; Raad, Farah S.; Leng, Siwei; Wex, Brigitte; Cheng, Stephen Z.D.; Eichhorn, S. Holger; Kaafarani, Bilal R.
• Is Part Of: Tetrahedron. Volume 71:Issue 2(2015)
• Page Start: 308
• Page End: 314
• Publication Date: 2015-01-14
• Subjects: Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2014.11.050
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: Reported here is the columnar mesomorphism of board shaped dyes based on quinoxalino[2′, 3′:9, 10]phenanthro[4, 5- abc ]phenazine (TQPP) derivatives that was induced by an increase in lateral bulk. TQPP derivatives with protons, tert -butyl and 4- tert -butyl-phenyl groups in positions 2 and 11 are compared, as well as dodecylthio, dodecyloxy, phytanylthio, and phytanyloxy side-chains. Only derivatives with 4- tert -butyl-phenyl groups display columnar liquid crystal phases over wide ranges of temperature while all other TQPPs are not liquid crystalline except for the compound with tert -butyl groups and phytanyloxy side-chains that shows a Colr mesophase over a temperature range of 26 °C. The sole attachment of phytanyl groups does not effectively induce columnar mesophases. However, the lateral attachment of bulky groups to the TQPP core induces columnar mesomorphism because of the in-plane aspect ratio decrease and the favored twisted or helical π-stacking of the molecules in columns rather than the parallel co-planar packing. Graphical abstract: