Investigation of high Δεderivatives of the [closo-1-CB9H10]−anion for liquid crystal display applications

Pecyna, Jacek; Kaszyński, Piotr; Ringstrand, Bryan; Bremer, Matthias

doi:10.1039/c4tc00230j

Cited by 21 publications

(29 citation statements)

References 24 publications

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“…2 In this context, we initially investigated 1-sulfonium derivatives of type IA, 3,4 and later we developed a convenient method for access to 1-pyridinium zwitterions of anions A and B. 5 Although materials of type IA and IB are effective additives that increase dielectric anisotropy Δε of a nematic liquid crystal host, these polar materials rarely exhibit liquid crystalline properties themselves, have high melting points, and display limited solubility in nematic hosts.…”

Section: ■ Introductionmentioning

confidence: 99%

Synthesis and Characterization of 12-Pyridinium Derivatives of the [closo-1-CB₁₁H₁₂]⁻ Anion

et al. 2014

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Diazotization of [closo-1-CB11H10-1-R-12-NH2](-)[NMe4](+) (4[NMe4]) in neat 4-methoxypyridine leads to 12-(4-methoxypyridinium) zwitterions [closo-1-CB11H10-1-R-12-(4-MeOC5H4N)] (2) in ∼50% yield. Demethylation of 2 with LiCl in dimethylformamide provides access to 12-pyridones 5[NMe4], which can be O-alkylated with alkyl triflates giving 12-(4-alkoxypyridinium) zwitterions, such as 1. This three-step process is more efficient than direct diazotization of amine 4[NMe4] in neat higher 4-alkoxypyridine. The new method was demonstrated for the synthesis of [closo-1-CB11H10-1-C5H11-12-(4-C7H15OC5H4N)] (1c), which exhibits a smectic A phase. Molecular and electronic structures of 4-methoxypyridinium zwitterion 2b and its C(1) isomer [closo-1-CB11H11-1-(4-MeOC5H4N)] (3b) were investigated by single-crystal X-ray diffraction and spectroscopic methods, respectively, and the experimental results were compared to those obtained with density functional theory methods. Lastly, the mechanism for formation of zwitterions 2 was investigated computationally revealing low energy for dediazoniation of the [closo-1-CB11H10-1-R-12-N2] (14) intermediate (ΔG298 ≈ 25 kcal/mol) to form boronium ylide 15, with weak dependence on substituent R. Dinitrogen derivative 14c was observed by (11)B NMR spectroscopy.

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Section: ■ Introductionmentioning

confidence: 99%

Synthesis and Characterization of 12-Pyridinium Derivatives of the [closo-1-CB₁₁H₁₂]⁻ Anion

et al. 2014

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“…1) have high dielectric anisotropy D3 and are useful additives to nematic materials for LCD. In this context, we developed a synthetic methodology and prepared 1-sulfonium 3,4 and 1-quinuclidinium, 3 and also 10-sulfonium 4-6 and 10-pyridinium 7 zwitterions, compounds of the general structure IIA and IA. Some of them exhibit nematic behavior and D3 reaching a record high value of 113.5(!)…”

Section: Introductionmentioning

confidence: 99%

Zwitterionic pyridinium derivatives of [closo-1-CB₉H₁₀]⁻and [closo-1-CB₁₁H₁₂]⁻as high Δεadditives to a nematic host

2014

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“…In diketonate and BODIPY derivatives such as 1 or subphthalocyanines, the boron atom is surrounded by af latm esogenic p-system, which not only contributes to the liquid crystalline self-assembly,b ut also adds favorable absorption and emission characteristics. In contrast, the bulky closo-carboranes 2 are incorporated into rigid rod-likeu nits to obtain suitable mesomorphicp roperties.T hese boron clusters are not only suitable for liquid crystal display applicationsd ue to their high dielectric anisotropy De, [31,36,37] but also as battery electrolytes. [38] Moreover,t hey provided insight into fundamental aspects of soft matter such as the contribution of Coulomb and dipolar interactions on the stabilization of mesophases.…”

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Thermotropic MIDA Boronates as a Case Study for the Role of Dipolar Interactions in Liquid Crystalline Self‐Assembly

Wöhrle

Gündemir

Frey

et al. 2017

Chemistry A European J

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A series of MIDA (N-methylimino diacetic acid) boronates carrying 4-alkoxy, 3,4-bisalkoxy, or 3,4,5-trisalkoxyphenyl substituents were synthesized and their mesomorphic properties characterized by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD) techniques such as small- and wide-angle X-ray scattering (SAXS and WAXS, respectively). Most derivatives were liquid crystalline. In the case of mono- and bisalkoxy-substituted derivatives, C chains already induced smectic A (SmA) mesophases despite the bulky MIDA head group. With increasing chain length, columnar hexagonal (Col ) phases replaced SmA phases in the disubstituted series. Quantum chemical calculations on a series of MIDA boronates show that the B-N bond is a dative bond with a positive charge on the boron atom and negative charges on the nitrogen and oxygen atoms. In addition, no π-interaction between the aryl moiety and B-N bond was found, thus the mesogenic unit is electronically decoupled from the MIDA head group. These theoretical findings were supported by IR and Raman spectra as well as by asingle crystal structure analysis of 4-ethoxyphenyl MIDA boronate. Calculations of the electrostatic potential of the MIDA boronate reveal a special polarity pattern that can support the formation of a two-dimensional network and is likely to explain the liquid crystalline self-assembly. The absence of any electronic cross-talk between the MIDA head group and B-aryl or B-alkyl substituents allows the efficient tailoring of the mesophase type through variation of the substituents.

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Investigation of high Δεderivatives of the [closo-1-CB₉H₁₀]⁻anion for liquid crystal display applications

Abstract: Two series of sulfonium zwitterions of the [closo-1-CB9H10]− anion were prepared and investigated as high Δε additives to nematics.

Cited by 21 publications

References 24 publications

Synthesis and Characterization of 12-Pyridinium Derivatives of the [closo-1-CB₁₁H₁₂]⁻ Anion

Synthesis and Characterization of 12-Pyridinium Derivatives of the [closo-1-CB₁₁H₁₂]⁻ Anion

Zwitterionic pyridinium derivatives of [closo-1-CB₉H₁₀]⁻and [closo-1-CB₁₁H₁₂]⁻as high Δεadditives to a nematic host

Thermotropic MIDA Boronates as a Case Study for the Role of Dipolar Interactions in Liquid Crystalline Self‐Assembly

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Investigation of high Δεderivatives of the [closo-1-CB9H10]−anion for liquid crystal display applications

Abstract: Two series of sulfonium zwitterions of the [closo-1-CB9H10]− anion were prepared and investigated as high Δε additives to nematics.

Cited by 21 publications

References 24 publications

Synthesis and Characterization of 12-Pyridinium Derivatives of the [closo-1-CB11H12]− Anion

Synthesis and Characterization of 12-Pyridinium Derivatives of the [closo-1-CB11H12]− Anion

Zwitterionic pyridinium derivatives of [closo-1-CB9H10]−and [closo-1-CB11H12]−as high Δεadditives to a nematic host

Thermotropic MIDA Boronates as a Case Study for the Role of Dipolar Interactions in Liquid Crystalline Self‐Assembly

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Investigation of high Δεderivatives of the [closo-1-CB₉H₁₀]⁻anion for liquid crystal display applications

Synthesis and Characterization of 12-Pyridinium Derivatives of the [closo-1-CB₁₁H₁₂]⁻ Anion

Synthesis and Characterization of 12-Pyridinium Derivatives of the [closo-1-CB₁₁H₁₂]⁻ Anion

Zwitterionic pyridinium derivatives of [closo-1-CB₉H₁₀]⁻and [closo-1-CB₁₁H₁₂]⁻as high Δεadditives to a nematic host