Proton conduction in discotic mesogens

Basak, Durga; Christensen, Scott; Surampudi, Sravan K.; Versek, Craig; Toscano, Dan; Tuominen, Mark; Hayward, Ryan C.; Venkataraman, D.

doi:10.1039/c1cc10509d

Cited by 29 publications

(25 citation statements)

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“…There is thus widespread interest in developing anhydrous PEMs that operate at higher temperatures. Several groups have studied PEMs composed of amphiprotic organic groups tethered to polymeric backbones, only to find exponentially low conductivities [16][17][18][19][20][21]. This points to a lack of fundamental understanding into how tethering of amphiprotic groups influences hydrogen bond networks in such materials.…”

Section: Introductionmentioning

confidence: 97%

“…The relatively high proton conductivities in azole liquids are believed [2] to arise from enhanced mobility through Grotthuss shuttling [23], a proton transfer process involving collective hydrogen bond fluctuations producing more efficient proton jumps than through the so-called vehicular mechanism [24,25]. In search of PEMs with thermal and mechanical stability as well as high conductivity, several groups have studied azoles tethered to organic polymers [16,26], liquid crystalline supports [21], and inorganic supports [27]. The resulting conductivities for tethered azoles are typically suppressed by orders of magnitude from the corresponding neat liquid values [16].…”

Section: Introductionmentioning

confidence: 99%

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Simulating hydrogen-bond clustering and phase behaviour of imidazole oligomers

et al. 2012

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We have modelled structures and dynamics of hydrogen bond networks that form from imidazoles tethered to oligomeric aliphatic backbones in crystalline and glassy phases. We have studied the behaviour of oligomers containing 5 or 10 imidazole groups. These systems have been simulated over the range 100-900 K with constantpressure molecular dynamics using the AMBER 94 forcefield, which was found to show good agreement with ab initio calculations on hydrogen bond strengths and imidazole rotational barriers. Hypothetical crystalline solids formed from packed 5-mers and 10-mers melt above 600 K, then form glassy solids upon cooling. Viewing hydrogen bond networks as clusters, we gathered statistics on cluster sizes and percolating pathways as a function of temperature, for comparison with the same quantities extracted from neat imidazole liquid. We have found that, at a given temperature, the glass composed of imidazole 5-mers shows the same hydrogen bond mean cluster size as that from the 10-mer glass, and that this size is consistently larger than that in liquid imidazole. Hydrogen bond clusters were found to percolate across the simulation cell for all glassy and crystalline solids, but not for any imidazole liquid. The apparent activation energy associated with hydrogen bond lifetimes in these glasses (9.3 kJ mol À1 ) is close to that for the liquid (8.7 kJ mol À1 ), but is substantially less than that in the crystalline solid (13.3 kJ mol À1 ). These results indicate that glassy oligomeric solids show a promising mixture of extended hydrogen bond clusters and liquid-like dynamics.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Simulating hydrogen-bond clustering and phase behaviour of imidazole oligomers

et al. 2012

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“…Все соединения являлись звездообразными производ-ными трифенилена с установленным типом мезо-морфизма [2][3][4][5][6][7][8], часть из них имела в своей структуре гетероциклические фрагменты (рис. 1).…”

Section: экспериментunclassified

“…В последние годы активно развивается область создания самоорганизующихся функ-циональных наноматериалов, к которым относятся и жидкокристаллические звездообразные произ-водные трифенилена, особенно те, которые включают оксадиазольные и другие гетеро-циклические фрагменты [1][2][3][4][5][6][7][8]. Такие соединения имеют широкие перспективы применения в наноэлектронике, фотолюминесцентных приборах, в светоизлучающих диодах, солнечных батареях, сенсорных системах, хроматографии и др.…”

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Using Molecular Parameters in Forecasting the Mesomorphism of Star-Shaped Discotic Triphenylene Derivatives

Akopova¹,

Kovaleva²,

Усольцева³

et al. 2016

Liq. Cryst. and their Appl.

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“…10 The 1,2,3-triazole rings 45 that result from the CuAAC may also benefit self-organization and electronic properties of the generated adducts due to their strong dipole and aromatic character. Both, calamitic, [11][12][13] polymeric, 14 and discotic [15][16][17] liquid crystals containing the 1,2,3triazole motive have recently been reported. 50 Surprisingly, neither CuAAC nor thermally activated AAC have been employed for the cross-linking of Langmuir films and mesophases.…”

Section: Introductionmentioning

confidence: 99%

Cross-linking of discotic tetraazaporphyrin dyes in 2 and 3 dimensions by “click” chemistry

et al. 2013

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An intrinsic shortcoming of self-organizing materials is their susceptibility to structural changes by mechanical forces and exposure to chemicals and radiation. Cross-linking of the molecules in the desired supramolecular structure is a generally applicable pathway to structurally more stable materials but is difficult to apply to self-organizing materials because the introduction of cross-linkable groups affects their self-organization and the process of cross-linking may alter the supramolecular structure of the 10 preceding phase. Reported here are the synthesis, thermal properties, and cross-linking of octaalkylthio substituted tetraazaporphyrins that contain either eight terminal azide groups or eight terminal acetylene groups. Synthesis of these compounds requires the preparation of the azide and alkyne containing sidechains and their reaction with 1,2-dicyanoethylene-1,2-dithiolate to the corresponding maleodinitrile intermediates. All maleodinitriles are successfully converted to tetraazaporphyrins by the established Mg 15 templated cyclotetramerization in typical yields of 60-70%. Thermal properties of the metal-free and copper(II) metallated tetraazaporphyrins were studied by thermal gravimetric analysis, polarized optical microscopy, differential scanning calorimetry, and variable temperature powder X-ray diffraction measurements. Azide substituted tetraazaporphyrins with trimethylene and hexamethylene spacers as well as acetylene derivatives with with trimethylene spacers unexpectedly display columnar mesophases over 20 ranges of temperature from 30 ºC to 110 ºC. A thermally activated cross-linking of a hexagonal columnar mesophase by cycloaddition at 65 ºC is demonstrated for a 1:1 mixture of azide and acetylene derivatives. At this temperatures the reaction progresses for up to 48 hours but renders the mesophase insoluble and stable to above 200 ºC. The structure of the mesophase is surprisingly little affected by the cross-coupling process that reaches a conversion of 60% of all azide and acetylene groups based on IR measurements. 25 Conversion of up to 80% of azide and acetylene groups is reached by copper catalysed cross-linking of a 1:1 mixture in solution to generate insoluble polymers. A similar degree of conversion is achieved by copper catalysed cross-linking of a 1:1 mixture as Langmuir film after 3 hours. However, transfer of intact cross-linked Langmuir films onto substrates was not successful.

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Proton conduction in discotic mesogens

Abstract: In this communication, we show that liquid crystalline phases lower the activation energy barrier for proton transport. The liquid crystalline phases were obtained using a triphenylene core with alkyl chains bearing a triazole moiety at their termini.

Cited by 29 publications

References 27 publications

Simulating hydrogen-bond clustering and phase behaviour of imidazole oligomers

Simulating hydrogen-bond clustering and phase behaviour of imidazole oligomers

Using Molecular Parameters in Forecasting the Mesomorphism of Star-Shaped Discotic Triphenylene Derivatives

Cross-linking of discotic tetraazaporphyrin dyes in 2 and 3 dimensions by “click” chemistry

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