To be or not to be – nematic liquid crystals from shape-persistent V-shaped nematogens with the ‘magic angle’

References

• Klasen-Memmer M, Hirschmann H. Nematic liquid crystals for display applications. In: Goodby JW, Collings PJ, Kato T, et al., editors. Handbook of liquid crystals. 2nd. Vol. 3, Weinheim: Wiley-VCH, 2014. p. 105–129. Chapter 4
   Google Scholar
• Mandle RJ, Goodby JW. Designing principles and synthesis of materials for nematic liquid crystals. In: Goodby JW, Collings PJ, Kato T, et al., editors. Handbook of liquid crystals. 2nd. Vol. 3, Weinheim: Wiley-VCH, 2014. p. 63–101. Chapter 3
   Google Scholar
• Cammidge AN, Gopee H. Design and synthesis of nematic phases formed by disk-like molecules. In: Goodby JW, Collings PJ, Kato T, et al., editors. Handbook of Liquid Crystals. 2nd. Vol. 3, Weinheim: Wiley-VCH, 2014. p. 293–334. Chapter 10
   Google Scholar
• Freiser MJ. Ordered states of a nematic liquid. Phys Rev Lett. 1970;24:1041–1043.
   Web of Science ®Google Scholar
• Yu J, Saupe A. Observation of a biaxial nematic phase in potassium laurate-1-decanol-water mixtures. Phys Rev Lett. 1980;45:1000–1004.
   Web of Science ®Google Scholar
• van de Pol E, Thies-Weesie DME, Petukhov AV, et al. Uniaxial and biaxial liquid crystal phases in colloidal dispersions of board-like particles. Liq Cryst. 2010;37:641–651.
   Web of Science ®Google Scholar
• Lehmann M, Görtz V. Design of biaxial nematic mesogens. In: Goodby JW, Collings PJ, Kato T, et al., editors. Handbook of liquid crystals. 2nd. Vol. 3, Weinheim: Wiley-VCH, 2014. p. 335–373. Chapter 11
   Google Scholar
• Lehmann M. Low molar mass thermotropic systems. In: Luckhurst GR, Sluckin TJ, editors. Biaxial nematic liquid crystals. Chichester: Wiley; 2015. p. 333–367. Chapter 14.
   Google Scholar
• Tschierske C, Photinos D. Biaxial nematic phases. J Mater Chem. 2010;20:4263–4294.
   Web of Science ®Google Scholar
• Luckhurst GR. Biaxial nematic liquid crystals: fact or fiction? Thin Solid Films. 2001;393:40–52.
   Web of Science ®Google Scholar
• Teixeira PIC, Masters AJ, Mulder BM. Biaxial nematic order in the hard-boomerang fluid. Mol Cryst Liq Cryst. 1998;323:167–189.
   Web of Science ®Google Scholar
• Bates MA. Bent core molecules and the biaxial nematic phase: a transverse dipole widens the optimal angle. Chem Phys Lett. 2007;437:189–192.
   Web of Science ®Google Scholar
• Lehmann M, Kang SW, Köhn C, et al. Shape-persistent V-shaped mesogens—formation of nematic phases with biaxial order. J Mater Chem. 2006;16:4326–4334.
   Web of Science ®Google Scholar
• Lehmann M, Köhn C, Kresse H, et al. Synthesis and properties of oxadiazole based V-shaped, shape persistent nematogens. Chem Commun. 2008;1768–1770.
   PubMed Web of Science ®Google Scholar
• Lehmann M, Seltmann J, Auer AA, et al. Synthesis and mesomorphic properties of new V-shaped shape-persistent nematogens containing a thiazole or a thiadiazole bending unit. J Mater Chem. 2009;19:1978–1988.
   Web of Science ®Google Scholar
• Seltmann J, Müller K, Klein S, et al. V-shaped nematogens with the “magic bent angle”. Chem Commun. 2011;47:6680–6682.
   PubMed Web of Science ®Google Scholar
• Lehmann M, Köhn C, Cruz C, et al. Biaxial nematic mesophases from shape-persistent mesogens with a fluorenone bending unit. Chem Eur J. 2010;16:8275–8279.
   PubMed Web of Science ®Google Scholar
• Campbell NL, Duffy WL, Thomas GI, et al. Nematic 2,5-disubstituted thiophenes. J Mater Chem. 2002;12:2706–2721.
   Web of Science ®Google Scholar
• Kishikawa K, Harris MC, Swager TM. Nematic liquid crystals with bent-rod shapes: mesomorphic thiophenes with lateral dipole moments. Chem Mater. 1999;11:867–871.
   Web of Science ®Google Scholar
• Paraskos AJ, Swager TM. Effects of desymmetrization on thiophene-based bent-rod mesogens. Chem Mater. 2002;14:4543–4549.
   Web of Science ®Google Scholar
• Kang S, Saito Y, Watanabe N, et al. Low-birefringent, chiral banana phase below calamitic nematic and/or smectic C phases in oxadiazole derivatives. J Phys Chem B. 2006;110:5205–5214.
   PubMed Web of Science ®Google Scholar
• Takazoe H, Takanishi Y. Bent-core liquid crystals: their mysterious and attractive world. Jpn J Appl Phys. 2006;45:597–625.
   Web of Science ®Google Scholar
• Dimitrowa K, Hauschild J, Zaschke H, et al. Kristallin-flüssige 1,3,4-Thiadiazole. I. Biphenyl- und terphenylanaloge 1,3,4-Thiadiazole. J Prakt Chem. 1980;322:933–944.
   Google Scholar
• Yuan WZ, Yu Z, Lu P, et al. High efficiency luminescent liquid crystal: aggregation-induced emission strategy and biaxially oriented mesomorphic structure. J Mater Chem. 2012;22:3323–3326.
   Web of Science ®Google Scholar
• Yohida S, Fujii M, Aso Y, et al. Novel electron acceptors bearing a heteroquinonoid system. 4. Syntheses, properties, and charge-transfer complexes of 2,7-Bis(dicyanomethylene)-2,7-dihydrobenzo[2,1-b:3,4-b’]dithiophene, 2,7-Bis(dicyanomethylene)-2,7-dihydrobenzo[1,2-b:4,3-b’]dithiophene, and 2,6-Bis(dicyanomethylene)-2,6-dihydrobenzo[1,2-b:4,5-b’]dithiophene. J Org Chem. 1994;59:3077–3081.
   Web of Science ®Google Scholar
• Baldoli C, Bossi A, Giannini C, et al. A novel and efficient approach to (Z)-1,2-Bis(benzodithienyl)ethene ­precursors of Tetrathia[7]helicenes. Synlett. 2005;7:1137–1141.
   Google Scholar
• Larsen J, Bechgaard K. Thiaheterohelicenes. 1. Synthesis of unsubstituted Thia[5]-, [9]- and [13]heterohelicenes. Acta Chemica Scandinavica. 1996;50:71–76.
   Google Scholar
• Knochel P, Dohle W, Gommermann N, et al. Highly functionalized organomagnesium reagents prepared through halogen—metal exchange. Angew Chem Int Ed. 2003;36:4302–4320.
   Google Scholar
• Koßmehl G, Hoppe FD, Hirsch B. Liquid crystalline compounds in the thiophene series, part 6+ synthesis and characterization of azomethines and vinylenes with two mesogenic groups and different alkylene spacer lengths. Z Naturforsch. 1993;48b:826–843.
   Google Scholar
• Zheng C, Pu S, Xu J, et al. Synthesis and the effect of alkyl chain length on optoelectronic properties of diarylethene derivatives. Tetrahedron. 2007;63:5437–5449.
   Web of Science ®Google Scholar
• Ma X, Ma F, Zhao Z, et al. Synthesis and properties of NLO chromophores with fine-tuned gradient electronic structures. J Mater Chem. 2009;19:2975–2985.
   Web of Science ®Google Scholar
• Abdoh MMM, Srinivasa, Shivaprakash NC, et al. Synthesis and properties of NLO chromophores with fine-tuned electronic structures. Chem Phys. 2009;77:2570–2578.
   Google Scholar
• Goto Y, Ogawa T, Sawada S, et al. Fluorinated liquid crystals for active matrix displays. Mol Cryst Liq Cryst. 1991;209:1523–1530.
   Web of Science ®Google Scholar
• Wu ST, Margerum JD, Ho MS, et al. High birefringent liquid crystals. Mol Cryst Liq Cryst. 1995;261:79–86.
   Web of Science ®Google Scholar
• Petrzilka M. Polar acetylenic liquid crystals with broad mesomorphic ranges. The positional influence of different C, C-Elements on the Transition Temperatures. Mol Cryst Liq Cryst. 1984;111:329–346.
   Web of Science ®Google Scholar
• Imrie CT, Henderson PA. Liquid crystal dimers and higher oligomers: between monomers and polymers. Chem Soc Rev. 2007;36:2096–2124.
   PubMed Web of Science ®Google Scholar
• Dingemans J, Murthy NS, Samulski ET. Javelin-, hockey stick-, and boomerang-shaped liquid crystals. Structural variations on p-Quinquepheny. J Phys Chem B. 2001;105:8845–8860.
   Web of Science ®Google Scholar