Synthesis and thermotropic liquid crystalline properties of calamitic molecules with laterally attached hydrophilic groups: Y-shaped three-block molecules which can form smectic and columnar mesophases

The structures of seven benzene derivatives [1,2,3-tri(bromomethyl)benzene, (1); 3,5-di(bromomethyl)bromobenzene, (2); 2,5-di(bromomethyl)bromobenzene, (3); 4-(bromomethyl)-2,5-dibromotoluene, (4); 4-(bromomethyl)bromobenzene, (5); 2,3-di(bromomethyl)bromobenzene, (6) and (bromomethyl)-p-dibromobenzene, (7)] with bromo and bromomethyl (and in one case methyl) substituents are presented and analysed in terms of Br···Br interactions up to 4.0Å, supported by hydrogen bonds H···Br. Some interactions of the type Br···π and π···π are encountered and play a subordinate role in the packing. Despite the close chemical similarity of the compounds, some of which are isomers with permuted substituent positions, the packing motifs are highly variable. Compounds 2-5 are based on layer structures with Br n (n = 3, 4) and/or mixed Br/C rings. Compounds 1, 6 and 7 display three-dimensional packings of differing complexity, but with interpretable substructures; 1 can be analysed in terms of ribbons of linked Br 3 and Br 4 rings; 6 displays chains of linked Br 3 triangles; 7 consists of ribbons of linked Br 4 quadrilaterals.

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“…Spectroscopic data for compounds 1 [18], 2 [19], 3 [20], 4 [21], 5 [22,23], 6 [24,25], and 7 [26] agree with those reported in …”

Section: Methodssupporting

confidence: 77%

X-Ray Structure Determinations of Bromo- and/or Bromomethylsubstituted Benzenes: C–H···Br, C–Br···Br, and C–Br···π Interactions

Jones

Kuś

Dix

2012

Zeitschrift Für Naturforschung B

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“…Such a microsegregation effect was considered to be the driving force for the formation of the smectic phase (18,19). The high stability of either the smectic C or nematic phase of BBOXD-n, indicated the presence of strong intermolecular interaction which might have stabilised the parallel alignment of molecules (20)(21)(22)(23)(24). In order to evaluate the molecular arrangements in their mesophases, XRD was performed on BBOXD-n at different temperatures.…”

Section: Resultsmentioning

confidence: 99%

A new series of liquid‐crystalline bi‐1,3,4‐oxadiazole derivatives: synthesis and mesomorphic behaviour

Zhang

Wang

et al. 2008

Liquid Crystals

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A new series of liquid-crystalline bi-1,3,4-oxadiazole derivatives: synthesis and mesomorphic behaviour, Liquid Crystals, 35:4, 389-394, Symmetrical bi-1,3,4-oxadiazole derivatives, namely 5,59-bis(phenyl 4-alkoxybenzoate)-2,29-bi-1,3,4-oxadiazole (BBOXD-n, n56, 10, 14, 16), were synthesised. All BBOXD-n exhibited remarkably stable SmC phases by virtue of the high transition enthalpies of SmC-I. In addition, BBOXD-6 and BBOXD-10 showed an enantiotropic nemetic phase with enthalpies of the N-I transition up to 5.16 kJ mol 21 . As confirmed by wide-angle X-ray diffraction analysis and MM2, molecules of BBOXD-n showed high-angle tilting (55-57u) within their smectic C phases.

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“…[51] In that case, a more destabilising effect was observed if the lateral group is located at a more centred position of the rigid core. The opposite effect we observe here may be because of moving the lateral methyl group to a more peripheral position brings it closer to the terminal methoxy substituent of the biphenyl moiety, which probably is too short to compensate for unfavourable lateral repulsion.…”

Section: Thermal Propertiesmentioning

confidence: 94%

Coumarin-based emissive liquid crystals

Buchs

Gäbler²,

Janietz

et al. 2014

Liquid Crystals

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Calamitic luminophores are presented based on an elongated aryl-substituted coumarin core. The substitution pattern at terminal and lateral positions were systematically modified. The new compounds exhibit smectic C and/or nematic liquid crystalline phases. The chromophores show fluorescence in the blue spectral region. The benzopyranones are miscible with acrylate-substituted reactive nematic mesogens. Uniaxial orientation of the mixed systems was achieved by surface-assisted alignment on polyimide orientation layers. The film anisotropy was stabilised by subsequent photocrosslinking. The crosslinked oriented films display linear polarised photoluminescence upon isotropic excitation

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Synthesis and thermotropic liquid crystalline properties of calamitic molecules with laterally attached hydrophilic groups: Y-shaped three-block molecules which can form smectic and columnar mesophases

Cited by 40 publications

References 19 publications

X-Ray Structure Determinations of Bromo- and/or Bromomethylsubstituted Benzenes: C–H···Br, C–Br···Br, and C–Br···π Interactions

X-Ray Structure Determinations of Bromo- and/or Bromomethylsubstituted Benzenes: C–H···Br, C–Br···Br, and C–Br···π Interactions

A new series of liquid‐crystalline bi‐1,3,4‐oxadiazole derivatives: synthesis and mesomorphic behaviour

Coumarin-based emissive liquid crystals

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