Effect of Alkylthio Tail on Phase Behaviors of Bent-shaped Molecules Based on Naphthalene Core

Li, Xiaodong; Lee, Seng Kue; Kang, Sungmin; Tokita, Masatoshi; Kawauchi, Susumu; Watanabe, Junji

doi:10.1246/cl.2009.424

Cited by 28 publications

(17 citation statements)

References 9 publications

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“…We also note that the DFT models suggest that the two cyanobiphenyl units in the CBSnSCB dimers are inclined by a small angle with respect to each other unlike their parallel disposition in the other two series. For the odd members the similarity in behaviour between the CBSnSCB and CBnCB series may be accounted for in terms of the lower rotational barrier around the phenyl-S [53] and S-CH2 groups [54]. Thus, the nematic field can select more linear conformers at a lower energy cost than for the CBnCB series, and a similar argument was used to account for the high transition temperatures seen for flexible polysiloxane-based side chain liquid crystal polymers [55,56].…”

Section: Resultsmentioning

confidence: 99%

Sulfur-linked cyanobiphenyl-based liquid crystal dimers and the twist-bend nematic phase

et al. 2019

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The synthesis and characterisation of two series of cyanobiphenyl-based liquid crystal dimers containing sulfur links between the spacer and mesogenic units, the 4',4''-[1,ωalkanediylbis(thio)]bis-[1,1'-biphenyl]-4-carbonitriles (CBSnSCB), and 4'-({ω-[(4'cyano[1,1'-biphenyl]-4-yl)oxy]alkyl}thio)[1,1'-biphenyl]-4-carbonitriles (CBSnOCB), are described. The odd members of both series show twist-bend nematic and nematic phases whereas the even members exhibit only the nematic phase. An analogous cyanoterphenylbased dimer, 3 4-{6-[(4'-cyano[1,1'-biphenyl]-4-yl)thio]-hexyl}[1 1 ,2 1 :2 4 ,3 1-terphenyl]-1 4carbonitrile (CT6SCB), is also reported and shows enantiotropic NTB and N phases. The transitional properties of these dimers are discussed in terms of molecular curvature, flexibility and biaxiality. The same molecular factors influence also birefringence of nematic phases. Resonant X-ray scattering studies of twist-bend nematic phase at both the carbon and sulfur absorption edges were performed, which allowed for determination of critical behaviour of helical pitch at the transition to nematic phase, the behaviour was found independent on molecular structure. It was also observed that despite the different molecular bending angle and flexibility, in all compounds the helical pitch length far from the N-NTB transition corresponds to 4 longitudinal molecular distances.

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Section: Resultsmentioning

confidence: 99%

Sulfur-linked cyanobiphenyl-based liquid crystal dimers and the twist-bend nematic phase

et al. 2019

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“…Considering that the Col h phase has not been formed from the homologous molecules with alkoxy tail, 10) the rotational freedom of thio-ether linkage may make their accommodation possible. 24) Finally, we refer to the X phase observed in the highest temperature region for N(1,7)-S20. This phase is optically isotropic.…”

Section: Discussionmentioning

confidence: 99%

Unusual Formation of Switchable Hexagonal Columnar Phase by Bent-Shaped Molecules with Low Bent-Angle Naphthalene Central Core and Alkylthio Tail

Kang

Lee

et al. 2010

Jpn. J. Appl. Phys.

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The low-angle bent-shaped molecules with 1,7-naphthalene central core and alkylthio tails can form a novel hexagonal columnar phase and a dark B4 phase. The columnar phase has a large two-dimensional hexagonal lattice with edges of 65–75 Å and exhibits polar switching with spontaneous polarization along the column axis. Calculated from the density (∼1 g·cm-3) and unit volume, the number of molecules that are necessary to fill a 4.6-Å stratum of each column were found to be ∼11. Such a large number of molecules can be accommodated only in the tube-like assembly, which may be the first example as formed by the usual bent-shaped molecule with a single alkylthio tail.

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“…Because of the exibility of terminal alkyl chains and the valence between mesogens and terminal chain lengths in asymmetric structures, smectic A-to-columnar phase transitions have been reported in coil-rod-coil systems 38,39 and bolaamphiphiles. 40 Consequently, the balance between terminal chains and mesogens, the rotational freedom of the alkylthio linkage 41 and symmetric structure of the N(1,7)-EIE-Sn system may promote their transition motion, resulting in a replacement of the SmA phase with the columnar phase upon terminal chain lengthening. The current observation, in addition to our previous observations of cubic, Col h , X, B7 and B2 phases, 14,16,42 might be explained by a relationship between layer elastic constants and temperature.…”

Section: Resultsmentioning

confidence: 99%

Smectic A–hexagonal columnar–B7 phase transition of acute-angle bent-core molecules

et al. 2015

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Effect of Alkylthio Tail on Phase Behaviors of Bent-shaped Molecules Based on Naphthalene Core

Abstract: New bent-shaped molecules with naphthalene central core and alkylthio tail are prepared, and their banana phase structures and properties are discussed in comparison with those of conventional alkoxy molecules.

Cited by 28 publications

References 9 publications

Sulfur-linked cyanobiphenyl-based liquid crystal dimers and the twist-bend nematic phase

Sulfur-linked cyanobiphenyl-based liquid crystal dimers and the twist-bend nematic phase

Unusual Formation of Switchable Hexagonal Columnar Phase by Bent-Shaped Molecules with Low Bent-Angle Naphthalene Central Core and Alkylthio Tail

Smectic A–hexagonal columnar–B7 phase transition of acute-angle bent-core molecules

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