Synthesis, mesomorphic behaviour and optical anisotropy of some novel materials for nematic mixtures of high birefringenceElectronic supplementary information (ESI) available: experimental procedures for all compounds not already given in this paper. See http://www.rsc.org/suppdata/jm/b4/b400630e/

Hird, Michael; Toyne, Kenneth J.; Goodby, John W.; Gray, G. W.; Minter, Victoria; Tuffin, Rachel P.; McDonnell, D. G.

doi:10.1039/b400630e

Cited by 61 publications

(22 citation statements)

References 25 publications

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“…The melting temperature (T m , defined as the phase transition temperature between the Cr and LC phases) and the clearing temperature (T c , defined as the phase transition temperature between the LC an Iso phases) are much higher for 1aD than for 1aC (Figure 3a). This behavior is consistent with the linear and rigid structure of the CN group, which induces tight packing in an antiparallel direction owing to the large µ || value [37][38][39].…”

Section: Phase Transition Behaviorsupporting

confidence: 84%

Luminescence Tuning of Fluorinated Bistolanes via Electronic or Aggregated-Structure Control

et al. 2019

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Organic luminescent materials have a wide range of practical applications, but the understanding of the relationship between molecular structure and luminescent behavior is lacking. Herein, we synthesized fluorinated bistolanes with an electron-donating alkoxy substituent at one terminal and an electron-withdrawing substituent at the other to realize systematic control of the electron-density distribution. Evaluation of the phase transition behavior revealed that most of the fluorinated bistolanes showed liquid-crystalline (LC) behavior, with the phase transition temperature depending on the terminal substituents. Additionally, the fluorinated luminophores displayed intense photoluminescence (PL) in solution and in their crystal phases. Remarkably, the PL color shifted dramatically depending on the dipole moment (μ||) along the long molecular axis; thus, PL tuning can be achieved through electronic modulation by precise control of the μ|| of the luminophore. Interestingly, in the LC phases under thermal conditions, the maximum PL band shifted by 0.210 eV upon phase transition from the crystal to smectic A LC phases, indicating that PL tuning can also be achieved by controlling the aggregated structure. These results offer a new molecular design for easily tunable PL materials using the molecular properties or external stimuli for promising applications, including light-emitting displays and PL sensing materials.

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Section: Phase Transition Behaviorsupporting

confidence: 84%

Luminescence Tuning of Fluorinated Bistolanes via Electronic or Aggregated-Structure Control

et al. 2019

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“…Seed et al designed and synthesised a series of compounds with 4-butylsulfanylphenyl and 4-cyano-or 4-isothiocyanato-phenyl units connected by ¾CH¼CH¾, ¾COO¾, ¾C;C¾, ¾C;C¾COO¾, ¾COS¾, ¾CSO¾, ¾CSS¾ linking groups, and showed that different substituted groups had great effects on optical anisotropy and polarisability anisotropy [20][21][22][23], and also synthesised compounds with mesogenic isothiocyanatonaphthalenes groups [24]; the newly synthesised compounds had high nematic phase thermal stabilities and relatively low melting points compared with compounds where the naphthalene and benzene rings were interchanged, and the analogous compounds where a cyano group replaced the isothiocyanate. Hird et al [25] pointed out that a construction of alkoxy-naphthylphenyl-ethynylisothiocyanato has ultra-high birefringence (up to 0.63).…”

Section: Introductionmentioning

confidence: 99%

“…It is reported that a high Án value can be realised by increasing the molecular conjugation length and designing the molecular shape [12][13][14][15][16][17][18][19][20][21][22][23][24][25]; representative functional groups that contribute to the molecular conjugation length include unsaturated rings such as phenyl, naphthalene, thiophene or other fused rings, and unsaturated bonds, carbon-carbon double or triple bonds, for example, and high polarisability groups such as cyano or isothiocyanate groups. For the molecules with unsaturated carbon-carbon bonds, diacetylene [26,27] and stilbene groups [28,29] should be avoided due to their instability under ultraviolet illumination.…”

Section: Introductionmentioning

confidence: 99%

Preparation and properties of highly birefringent liquid crystalline materials: styrene monomers with acetylenes, naphthyl, and isothiocyanate groups

Zhang¹,

Guan²,

Zhang³

et al. 2010

Liquid Crystals

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Two new series of styrene monomers with different alkyl chain length were successfully synthesised. The chemical structures of synthetic intermediates and monomers were confirmed by Fourier transform infrared spectroscopy, 1 H nuclear magnetic resonance spectroscopy, mass spectrometry and elemental analysis. Their thermal stability, transition temperatures and phase sequences were investigated by polarised light microscopy, thermogravimetric analysis, differential scanning calorimetry and one-dimensional wide-angle X-ray diffraction. The birefringent and photoelectric properties, UV-vis and fluorescence spectroscopy were also measured using Abbe refractometer and fluorescent apparatus. The results indicated that all the monomers exhibited a liquid crystalline phase at higher temperature, high birefringence values between 0.4 and 0.7, and good photoluminescence properties. Optical anisotropy of homologous molecules was reduced with the increase of alkyl chain length due to the decrease of molecular polarisation. Moreover, a significant effect of the chemical structure on the photoluminescence properties was also found and discussed according to the length of p-conjugation.

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“…Alkylcyanobiphenyls are well known largely due to their mesogenic properties, which were discovered by Gray in the 1970 th [ 1 – 2 ]. Alkylcyanobiphenyls and their analogs (e.g., dialkyl and alkoxy alkyl derivatives) are still being used as components of liquid crystal mixtures [ 3 – 8 ], lubricants [ 9 ], media for conformational analysis using NMR [ 10 – 12 ] and EPR [ 13 ] techniques, and nanoparticles-doped liquid crystals [ 14 ]. The classic multistage approaches to these compounds, including successive biphenyl acylation–reduction–halogenation–cyanodehalogenation ( Scheme 1 ) [ 15 ], are currently being replaced with methods based on transition-metal-catalyzed biaryl cross-coupling [ 16 – 21 ].…”

Section: Introductionmentioning

confidence: 99%

One-pot synthesis of 4′-alkyl-4-cyanobiaryls on the basis of the terephthalonitrile dianion and neutral aromatic nitrile cross-coupling

Peshkov¹,

Panteleeva²,

Wang³

et al. 2016

Beilstein J. Org. Chem.

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SummaryA convenient one-pot approach to alkylcyanobiaryls is described. The method is based on biaryl cross-coupling between the sodium salt of the terephthalonitrile dianion and a neutral aromatic nitrile in liquid ammonia, and successive alkylation of the long-lived anionic intermediate with alkyl bromides. The reaction is compatible with benzonitriles that contain methyl, methoxy and phenyl groups, fluorine atoms, and a 1-cyanonaphthalene residue. The variety of ω-substituted alkyl bromides, including an extra bromine atom, a double bond, cyano and ester groups, as well as a 1,3-dioxane fragment are suitable as alkylation reagents.

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Synthesis, mesomorphic behaviour and optical anisotropy of some novel materials for nematic mixtures of high birefringenceElectronic supplementary information (ESI) available: experimental procedures for all compounds not already given in this paper. See http://www.rsc.org/suppdata/jm/b4/b400630e/

Cited by 61 publications

References 25 publications

Luminescence Tuning of Fluorinated Bistolanes via Electronic or Aggregated-Structure Control

Luminescence Tuning of Fluorinated Bistolanes via Electronic or Aggregated-Structure Control

Preparation and properties of highly birefringent liquid crystalline materials: styrene monomers with acetylenes, naphthyl, and isothiocyanate groups

One-pot synthesis of 4′-alkyl-4-cyanobiaryls on the basis of the terephthalonitrile dianion and neutral aromatic nitrile cross-coupling

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