Abstract
Introduction: This is the first report on chiral polymorphic hydrazine-based asymmetric liquid crystal trimers, 1-[4'-(4''-(5-Cholesteryloxy)carbonyl)butyloxy]-3-[N-benzylideneoxy-N'-(4'''-decyloxybenzylidene) hydrazine] butyloxybenzenes, and 1-[4'-(4''-(10-cholesteryloxy)carbonyl)nonyloxy]-3-[N-benzylideneoxy-N'-(4'''- decyloxybenzylidene)hydrazine]butyloxybenzenes., in which the hydrazine and cholesterol arms were connected via two flexible methylene spacers (n = 3-12 units and m = 4 or 9, respectively) to the central resorcinol core.
Materials and Methods: FT-IR, 1D and 2D NMR spectroscopy, and CHN microanalysis were used to elucidate the structures of the trimers. Differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction were used to study the transitional and phase properties of the trimers, which were length and spacer parity dependent. Trimers with short spacer length in the cholesteryl arm, m = 4 showed an interesting phase sequence of BP/N*-TGBA*-SmA*.
Results and Discussion: The TGBA* phase was sensitive to spacer length as it was only observed in trimers with short ester linkage. For the long analogues, m = 9, characteristic visible reflection and a much simpler phase sequence with only N* and SmA* phases were observed.
Conclusion: The X-ray diffraction measurements revealed that layer periodicities of the SmA* phase were approximately half the estimated all-trans molecular length (d/L ≈ 0.44-0.52), thus suggesting that the molecules are either strongly intercalated or bent.
Keywords: Polymorphic, hydrazine, TGBA, blue phase, XRD, layer periodicity.
Graphical Abstract
[http://dx.doi.org/10.1080/02678292.2017.1326635]
[http://dx.doi.org/10.1080/02678292.2018.1485978]
[http://dx.doi.org/10.1039/C9MH00428A]
[http://dx.doi.org/10.1039/b714102e] [PMID: 17982523]
[http://dx.doi.org/10.1080/02678290903157455]
[http://dx.doi.org/10.1016/j.tet.2009.05.076]
[http://dx.doi.org/10.1103/PhysRevE.84.031704] [PMID: 22060387]
[http://dx.doi.org/10.1039/b606617h]
[http://dx.doi.org/10.1039/b811716k] [PMID: 19082107]
[http://dx.doi.org/10.1007/s10965-013-0259-5]
[http://dx.doi.org/10.1080/00397910903040252]
[http://dx.doi.org/10.1080/02678292.2016.1197974]
[http://dx.doi.org/10.1080/02678292.2017.1408865]
[http://dx.doi.org/10.1007/s00216-014-8223-8] [PMID: 25366974]
[http://dx.doi.org/10.1016/j.bioorg.2015.12.007] [PMID: 26771129]
[http://dx.doi.org/10.1080/02678292.2015.1020454]
[http://dx.doi.org/10.1039/a907974b]
[http://dx.doi.org/10.1080/02678292.2012.698756]
[http://dx.doi.org/10.1080/02678292.2017.1323354]
[http://dx.doi.org/10.1016/j.molstruc.2018.03.093]
[http://dx.doi.org/10.1080/02678290500284355]
[http://dx.doi.org/10.1002/3527602054]
[http://dx.doi.org/10.1080/02678292.2010.490307]
[http://dx.doi.org/10.1080/02678292.2014.898343]
[http://dx.doi.org/10.1080/02678292.2011.613265]
[http://dx.doi.org/10.1080/15421400500377743]
[http://dx.doi.org/10.1039/a801128a]
[http://dx.doi.org/10.1039/b404319g]
[http://dx.doi.org/10.1080/02678290412331298067]
[http://dx.doi.org/10.1080/02678290500116235]
[http://dx.doi.org/10.1080/02678292.2010.494412]
[http://dx.doi.org/10.1080/02678290903271504]
[http://dx.doi.org/10.1016/j.tet.2008.10.085]
[http://dx.doi.org/10.1039/c2jm30943b]