Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. A Nature Research Journal. Ferroelectric thin-films are highly desirable for their applications on energy conversion, data storage and so on.

Molecular ferroelectrics had been expected to be a better candidate compared to conventional ferroelectric ceramics, due to its simple and low-cost film-processability. However, most molecular ferroelectrics are mono-polar-axial, and the polar axes of the entire thin-film must be well oriented to a specific direction to realize the macroscopic ferroelectricity.

To align the polar axes, an orientation-controlled single-crystalline thin-film growth method must be employed, which is complicated, high-cost and is extremely substrate-dependent. In this work, we discover a new molecular ferroelectric of quinuclidinium periodate, which possesses six-fold rotational polar axes. The multi-axes nature allows the thin-film of quinuclidinium periodate to be simply prepared on various substrates including flexible polymer, transparent glasses and amorphous metal plates, without considering the crystallinity and crystal orientation.

With those benefits and excellent ferroelectric properties, quinuclidinium periodate shows great potential in applications like wearable devices, flexible materials, bio-machines and so on.

Interest in ferroelectrics with switchable spontaneous polarizations under external electric fields has been driven by the extensive applications in ferroelectric random access memories, piezoelectric sensors, nonlinear optical devices, capacitors and so on 123. With the increasing demand on thin-film devices and printed electronics, the complicated film-processing procedures of inorganic ferroelectrics hampered their development 456and increasing attentions have been attracted to molecular ferroelectrics due to their simple full-solution processing and low-cost film-making.

In the past decade, studies on molecular ferroelectrics achieved great improvement and a series of new compounds have been discovered with spontaneous polarization and transition-temperature comparable or superior to those of inorganics 78910 Despite those advantages, in the aspect of practical applications, realization of macroscopic ferroelectricity on molecular thin-films is still challenging.

As most of molecular ferroelectrics are mono-polar-axial, which means the polarization can only be switched to two specific directions, the thin-film must be prepared with specific crystallographic orientation to maximize the effective polarization. With such a concern, one could only use either well-controlled epitaxial large area growth or polycrystalline film growth where polarization direction is randomized but the effective polarization intensity is sacrificed.

For example, our group has reported a molecular ferroelectric thin film of imidazolium perchlorate, showing high spontaneous polarization and superior electromechanical coupling, but the switchable spontaneous polarization can only be realized in micrometer-scale on the polycrystalline thin-film due to its mono-polar-axial nature 12 Encouragingly, a recent discovery of ferroelectricity in plastic crystal, quinuclidinium perrhenate, offers a ray of hope to solve this issue To be more specific, the majority of plastic crystals often belong to the high-symmetry cubic point groups in the high-temperature paraelectric phase and have more than three polarization axes.

At room temperature, 1 possesses six-fold polar axes with a spontaneous polarization of 7. Therefore, similar to the orthorhombic ferroelectric phase of BaTiO 3there are six polarization axes existing in the crystal of 1.

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Comparing to the recently reported quinuclidinium perrhenate, 1 is a room-temperature molecular ferroelectric compound with more polar axes and higher spontaneous polarization a detailed comparison can be found in the Supplementary Table 1. Taking advantages of the six-fold polar axes and 12 polarization states, we have successful demonstrated macroscopic ferroelectric polarization reversal on thin-film samples prepared by simple aqueous solution process.

More importantly, such ferroelectricity does not require any orientation-controlled growth on specific substrate, which provide 1 great feasibility on making thin-film devices on various substrates, including flexible polymers. Such realization of macroscopic ferroelectricity on polycrystalline thin-films makes 1 a molecular ceramic-like ferroelectric. This discovery might open a new avenue for the device applications of molecular ferroelectrics, especially in flexible devices, wearable electronics, micromechanics and so on.

As a characteristic of ferroelectrics, 1 has a high-temperature paraelectric phase and a low-temperature ferroelectric phase for crystal data, see Supplementary Data 1 and 2and Supplementary Table 2. For temperature above the phase-transition temperature T c1 is in the high-temperature phase HTPwhich is in the cubic space group Pm m.

The same orientation of the structures was chosen for comparison purposes. H atoms were omitted for clarity. In the HTP, both the cation and the anion are located on the special sites, m mas shown in Fig.

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The intermolecular symmetries are not consistent with those of the crystallographic symmetry. The crystallographic symmetry can only be satisfied by disorder of the cation and anion. The modelled molecular structure can be understood as the average of multiple orientations.

Therefore, the multiple disorder in the HTP might be dynamical, which is characterized by heavy orientational or displacive disorder of molecules In our case, due to the spherical structure of the cation and anion, only severely orientational disorder was observed in the HTP of 1as illustrated in Fig.These metrics are regularly updated to reflect usage leading up to the last few days. Citations are the number of other articles citing this article, calculated by Crossref and updated daily.

Find more information about Crossref citation counts. The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric. Find more information on the Altmetric Attention Score and how the score is calculated. Quasi-spherical molecules have recently been developed as promising building blocks for constructing high-performance molecular ferroelectrics.

However, although the modification of spherical molecules into quasi-spherical ones can efficiently lower the crystal symmetry, it is still a challenge to precisely arouse a low-symmetric polar crystal structure. Systematic characterization indicates that [3-oxoquinuclidinium]ClO 4 is an excellent molecular ferroelectric with a high Curie temperature of K, a large saturate polarization of 6. This work demonstrates that the strategy of combining quasi-spherical molecule building blocks with directional intermolecular interactions provides an efficient route to precisely design new eminent molecular ferroelectrics.

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quinuclidinium

More by Jing Wang. More by Yin Rao. More by Wei-Qiang Liao.Crystal structure: contains datablocks I, global. DOI: Structure factors: contains datablocks I.

Quinuclidine

Additional supplementary materials: crystallographic information ; 3D view ; checkCIF report. For related literature see: Carroll et al.

Symmetry code: i. Our structural studies on [Re 2 OCl 10 ] 4- and [Re 2 OCl 10 ] 3- have shown that the appropriate choice of cation is crucial to obtain good structural parameters for the anion unit. The most suitable properties of the cation are low symmetry, chirality and the ability to form hydrogen bonds.

All these requirements are fulfilled by R - — hydroxyquinuclidinium cation. Quinuclidinium derivatives have been of interest due to their biological activity, especially as a acetylcholinesterase inhibitor Bosak et al. It was also proven that quinuclidinium salts protected rats against the toxicity of soman and tabun Sterling et al. Aside from the present study, the only other known structure of R - — hydroxyquinuclidinium was with RR -tartrate anion Erman et al.

The asymmetric unit of the crystal Fig. Similar rotation has also been observed, but with slightly smaller angles, in 3-hydroxyquinuclidinium tartrate Erman et al. The bond lengths of the cation are all normal and are in good agreement with quinuclidinium derivatives Carroll et al.

The anion is surrounded by six symmetry-related cations that act as hydrogen bond acceptors for O—H and N—H groups. The hydrogen bonds link cations and anions into infinite chains running in the a and b axis directions Figs. The title compound was obtained from a commercial source Aldrich and dissolved in hot methanol. Colourless crystals grew from the solution after a few hours. A view of R - - hydroxyquinuclidinium cation with atom labelling scheme.

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A view of molecular packing showing chains formed along a and b directions. The hydrogen bonds are shown as dashed lines. The H atoms not involved in any interaction are omitted for clarity. A view of R - - hydroxyquinuclidinium cations and chloride anion forming hydrogen bonds.The dissociation constant of I for the allosteric substrate inhibition site was 4. The protective index PI of I calculated from binding of I to both, catalytic and allosteric sites in AChE agreed with the measured PI; this confirms that allosteric binding contributes to the decrease of phosphorylation rates.

The toxicity i. All four compounds protected mice against Soman when given i.

Ether-free polyfluorenes tethered with quinuclidinium cations as hydroxide exchange membranes

One-quarter of the LD 50 dose fully protected mice survival of all animals against 2. This is a preview of subscription content, log in to check access. Rent this article via DeepDyve. Reprints and Permissions. Simeon-Rudolf, V. Quinuclidinium-imidazolium compounds: synthesis, mode of interaction with acetylcholinesterase and effect upon Soman intoxicated mice.

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Arch Toxicol 72, — Download citation. Issue Date : April Search SpringerLink Search. Immediate online access to all issues from Subscription will auto renew annually. Taxes to be calculated in checkout. You can also search for this author in PubMed Google Scholar.

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View author publications. Rights and permissions Reprints and Permissions. About this article Cite this article Simeon-Rudolf, V.Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.

We report on aryl ether-free 2,7-diphenylfluorene-based copolymers tethered with quinuclidinium Qui cations via hexyl spacers, prepared through superacid catalyzed Friedel—Crafts polycondensation and quaternization reactions. The 2,7-diphenylfluorene monomers were synthesised by Suzuki coupling and were employed to increase polymer backbone stiffness.

Corresponding copolymers and anion-exchange membranes AEMs tethered with piperidinium Pip and trimethylalkyl ammonium TMA cations were prepared as reference materials. Moreover, this membrane showed the highest thermal and alkaline stability in the series. The overall findings demonstrate that the combination of aryl ether-free backbone polymers and Qui cations results in durable and high-performance AEMs suitable for use in alkaline electrochemical energy conversion and storage devices.

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quinuclidinium

Pick and Choose.BoxSE 00, Lund, Sweden. E-mail: patric. We report on aryl ether-free 2,7-diphenylfluorene-based copolymers tethered with quinuclidinium Qui cations via hexyl spacers, prepared through superacid catalyzed Friedel—Crafts polycondensation and quaternization reactions. The 2,7-diphenylfluorene monomers were synthesised by Suzuki coupling and were employed to increase polymer backbone stiffness.

Corresponding copolymers and anion-exchange membranes AEMs tethered with piperidinium Pip and trimethylalkyl ammonium TMA cations were prepared as reference materials. Moreover, this membrane showed the highest thermal and alkaline stability in the series. The overall findings demonstrate that the combination of aryl ether-free backbone polymers and Qui cations results in durable and high-performance AEMs suitable for use in alkaline electrochemical energy conversion and storage devices.

Aromatic polymers functionalized with quaternary ammonium QA cations belong to the most studied class of AEM materials because of their availability, relative ease of synthesis, and generally high thermal, oxidative and hydrolytic stability. The spirocyclic 6-azonia-spiro[5. However, the results also indicate that the stability is highly dependent on precisely how the cations are attached to the polymer backbone.

In the present work we have prepared and studied AEMs based on aryl ether-free fluorene-based copolymers tethered with quinuclidinium Qui cations placed on flexible hexyl spacers. Qui is a bicyclic QA cation consisting of 6-membered rings in a rigid cage-like arrangement. First, a precursor copolymer was prepared by triflic acid catalyzed Friedel—Crafts polycondensation of trifluoroacetophenone and a balanced mixture of dialkyl- and dibromoalkyl-functionalized 2,7-diphenylfluorene monomers.

The latter monomers were synthesized and employed to increase backbone stiffness. Next, the precursor copolymer was quaternized to produce samples functionalized with Qui, Pip and trimethylalkyl ammonium TMA cations, respectively.

NaOH 60 ml solution for 5 days under a nitrogen atmosphere. During this period, the degassed 1 M aq. NaOH solution was replaced at least three times with fresh solution to ensure complete conversion. Next, the membranes were quickly washed five times with degassed de-ionized water until the rinse water was neutral.

The precursor copolymer was synthesized by a Friedel—Crafts type polycondensation reaction employing the two 2,7-diphenylfluorene monomers in combination with TFAp Scheme 1. The present polycondensation was effective and had a very high reaction rate. The signal of the methylene bromide —C H 2 Br protons appeared at 3.Crystal structure: contains datablocks global, I.

DOI: Structure factors: contains datablocks I. Additional supplementary materials: crystallographic information ; 3D view ; checkCIF report.

The cation is disordered about a mirror plane. The N—C and C—C bonds are somewhat shorter than those in the unsubstituted salt, and this has been attributed to the electron-withdrawing effect of the chlorine substituent Kurahashi et al. The present isomeric compound Scheme I is expected to show this feature; however, owing to disorder, the effect cannot be unambiguously observed even at low temperature. The commercially available compound was a crystalline.

A large block was cut into a smaller specimen. The cation is disordered about a mirror plane in the carbon atoms except C1 atom. The N1 and C1 atoms, which lie on this symmetry element, were refined with their normal half occupancies.

quinuclidinium

The other carbon atoms were refined with half occupancies, subject to N—C being restrained to 1. Additionally, the 1,3-related distances were restrained from 2. The anisotropic temperature factors of the disordered carbon were restrained to be nearly isotropic but the N—H distance was restrained to 0.

Carbon-bound H-atoms were placed in calculated positions C—H 0. The ammonium H-atom was located in a difference Fourier map, and was refined with an N—H distance restraint of 0. The dashed lines denote the hydrogen bond. National Center for Biotechnology InformationU.

Published online Apr Author information Article notes Copyright and License information Disclaimer. Correspondence e-mail: ym. Received Feb 27; Accepted Apr This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Open in a separate window. Supplementary Material Crystal structure: contains datablocks global, I.

quinuclidinium

Acknowledgments We thank the University of Malaya for the purchase of the diffractometer. Experimental The commercially available compound was a crystalline.

Refinement The cation is disordered about a mirror plane in the carbon atoms except C1 atom. References Barbour, L. Bruker