A New Role for Bboron in Advanced Materials

Kaszyński, Piotr; Lipiak, Dariusz

doi:10.1557/proc-374-341

Cited by 12 publications

(13 citation statements)

References 16 publications

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“…1). [19][20][21] closo-Monocarbaborates [closo-1-CB 9 H 10 ] À and [closo-1-CB 11 H 12 ] À (A and B, Fig. 1) belong to an extensive family of closo-boranes, which are characterized by sigma-aromaticity and complete negative charge delocalization.…”

Section: Introductionmentioning

confidence: 99%

Polar derivatives of the [closo-1-CB9H10]− cluster as positive Δε additives to nematic hosts

2009

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Polar (m z 16 D) and UV transparent >250 nm quinuclidinium (1) and sulfonium (2) zwitterionic derivatives of the [closo-1-CB 9 H 10 ] À anion were synthesized and studied as additives to nematic hosts. The molecular and crystal structures for 1 [C 19 H 44 B 9 N triclinic, P-1, a ¼ 9.766(2) A ˚, b ¼ 10.481(3) A ˚, c ¼ 12.098(3) A ˚, a ¼ 93.804( 9) , b ¼ 90.249(10) , g ¼102.587(10) , Z ¼ 2] were determined by X-ray crystallography and compared with the results of HF/6-31G(d) calculations. Low concentration solutions (<10 mol%) of 1 and 2 in ClEster host (D3 ¼ À0.59) were investigated using thermal and dielectric methods. The results for 1 and 2 showed virtual [T NI ] values of 139 C and 92 C, and D3 extrapolated to infinite dilution of 70 AE 1 and 61 AE 2, respectively. Dielectric results were analyzed using the Maier-Meier relationship and calculated molecular parameters. The apparent order parameter S app was found to be 0.63 and 0.50 for 1 and 2, respectively, which is smaller than that for the pure host (S ¼ 0.66). Analysis of the Kirkwood factors g obtained for each concentration gave an association constant K of 63 AE 2 and 37 AE 1 (model 1) for the assumed dimerization of molecules (2M # M 2 ) of 1 and 2, respectively, in solutions of ClEster.

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Section: Introductionmentioning

confidence: 99%

Polar derivatives of the [closo-1-CB9H10]− cluster as positive Δε additives to nematic hosts

2009

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“…The clusters also exhibit high electronic polarisability and low anisotropy, which would result in low birefringence and a high isotropic refractive index [19,20] for a boron cluster containing liquid crystal [21]. The clusters also have large molecular size and high symmetry axes [22] (D 5d and D 4d for the 12 and 10-vertex boron clusters, respectively) when compared to benzene and bicyclo[2.2.2]octane, and therefore have atypical distribution of their conformational minima [18].…”

Section: Boron Clusters and Liquid Crystalsmentioning

confidence: 99%

Boron clusters as structural elements of novel liquid crystalline materials

Ringstrand

2013

Liquid Crystals Today

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closo-Boranes are characterised by high thermal and oxidative stability due in part to highly delocalised bonding within a σ -framework. These boron clusters when employed as structural elements of liquid crystals give rise to novel structures with unique properties and vast potential in applications. The neutral closo-boranes such as the carboranes provide opportunity to perform fundamental structure-property relationship studies that may provide additional insight on the liquid crystalline state. The anionic closo-borates possessing a highly delocalised negative two charge can be used as structural elements of zwitterionic, quadrupolar liquid crystalline materials. Such materials may be of use for understanding the effects of polarity on the liquid crystalline state. Lastly, the anionic closo-monocarbaborates possessing a single highly delocalised negative charge can be envisioned as structural elements of either highly polar or ionic liquid crystalline materials. The highly polar materials may also serve as models for understanding the effects of polarity on the liquid crystalline state. Additionally, they should have application as positive ε additives for nematic liquid crystalline mixture formulations. The ionic materials, where the anionic fragment drives liquid crystalline behaviour, lend themselves as potential electrolytes for anisotropic ion transport in battery technologies. The review presented here introduces these concepts and highlights the current status of boron cluster containing liquid crystalline materials.

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“…Ten-vertex carboranylzinc is the only exception found so far, and it reacts with 4′-cyano-4-biphenyl triflate under the Negishi reaction conditions, giving a modest yield of the coupling product 29 (ref. 95 ). The analogous Pd-catalyzed coupling reactions of twelve-vertex para-carboranylzinc 96 or stannane 13 with iodobenzene or with aryl triflates were unsuccessful and no coupling product was observed.…”

Section: Carbon Substitutionmentioning

confidence: 99%

Four Decades of Organic Chemistry of closo-Boranes: A Synthetic Toolbox for Constructing Liquid Crystal Materials. A Review

Kaszyński

1999

Collect. Czech. Chem. Commun.

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Introduction and transformations of organic functional groups to ten- and twelve-vertex closo-boranes and heteroboranes is reviewed in the context of preparation of liquid crystalline compounds. The review, containing 198 references, is designed as a synthetic manual for materials chemists and focuses on methods for engineering molecules with elongated shapes and variable dipole moments. Several underdeveloped aspects of closo-borane chemistry are identified.

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A New Role for Bboron in Advanced Materials

Cited by 12 publications

References 16 publications

Polar derivatives of the [closo-1-CB9H10]− cluster as positive Δε additives to nematic hosts

Polar derivatives of the [closo-1-CB9H10]− cluster as positive Δε additives to nematic hosts

Boron clusters as structural elements of novel liquid crystalline materials

Four Decades of Organic Chemistry of closo-Boranes: A Synthetic Toolbox for Constructing Liquid Crystal Materials. A Review

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