Mesomorphic behaviour of 1,3-phenylene bis[4-(4-alkoxyphenyliminomethyl)benzoates] and related compounds

Akutagawa, Tomoyuki; Matsunaga, Yoshio; Yasuhara, K.

doi:10.1080/02678299408037337

Cited by 103 publications

(50 citation statements)

References 14 publications

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“…Takezoe et al 73 were the first to report ferroelectric measurements of the bent-core liquid crystals designed by Matsunaga (Fig. 5d) 74 . Occasionally, adjacent layers will have antiparallel polarizations that suppress ferroelectricity.…”

Section: Organization Of Molecular Dipolesmentioning

confidence: 98%

Supramolecular ferroelectrics

et al. 2015

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Supramolecular chemistry uses non-covalent interactions to coax molecules into forming ordered assemblies. The construction of ordered materials with these reversible bonds has led to dramatic innovations in organic electronics, polymer science and biomaterials. Here, we review how supramolecular strategies can advance the burgeoning field of organic ferroelectricity. Ferroelectrics - materials with a spontaneous and electrically reversible polarization - are touted for use in non-volatile computer memories, sensors and optics. Historically, this physical phenomenon has been studied in inorganic materials, although some organic examples are known and strong interest exists to extend the search for ferroelectric molecular systems. Other undiscovered applications outside this regime could also emerge. We describe the key features necessary for molecular and supramolecular dipoles in organic ferroelectrics and their incorporation into ordered systems, such as porous frameworks and liquid crystals. The goal of this Review is to motivate the development of innovative supramolecular ferroelectrics that exceed the performance and usefulness of known systems.

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Section: Organization Of Molecular Dipolesmentioning

confidence: 98%

Supramolecular ferroelectrics

et al. 2015

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“…The linking units for X, Y, X , and Y are numerous groups that can connect two phenyl rings or aromatic heterocycles, and the most commonly used groups are Schiff's base [9,29,30], ester including thioester [72][73][74], C=C double bond [35,75,76], C C triple bond [37,77], CH 2 O [78], CO 2 CH 2 [35], diazo [79], etc. Many direct bond linkages [36,80] should be avoided in a molecule because they would increase melting points and kill mesophases.…”

Section: General Molecular Structure Of Bent-core Lcsmentioning

confidence: 99%

“…In the real systems, achiral bent-core molecules 1 (P-n-OPIMBs) [9] and 2 [100,101] exhibiting SmCP phases obviously have opposite polar directions ( Fig. 6.8).…”

Section: Supermolecular Chirality and Macroscopic Polar Order In Bentmentioning

confidence: 99%

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Electric‐ and Light‐Responsive Bent‐Core Liquid Crystals: From Molecular Architecture and Supramolecular Nanostructures to Applications

Zhang¹

2013

Intelligent Stimuli‐Responsive Materials

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The three classic states of matter are well known and ubiquitous in everyday life: solid, liquid, and gas. Liquid crystals (LCs), an intermediate state between solid crystal and isotropic liquid, constitute a new fascinating class of condensed soft matter uniquely combining both fluidity and long-range order. The fluid-like mobility enables LCs to be switchable under external stimuli, and crystal-like long-range order bestows anisotropic physical properties on LCs. LCs can be divided into two main classes: thermotropic and lyotropic. Thermotropic LCs consist of individual molecules (or ion pairs) and exhibit phase transitions with the change of temperature. In this case, temperature is the fundamental thermodynamic factor determining mesophase formation. Lyotropic LCs are a special type of solution system that can form mesophases as a function of both temperature and concentration of LC molecules. The building block of a lyotropic phase is an aggregate (called a micelle) formed via self-assembly of many molecules (typically on the order of 100). Examples of LCs can be found both in the natural world and in technological applications. Thermotropic LCs find 189 190 ELECTRIC-AND LIGHT-RESPONSIVE BENT-CORE LIQUID CRYSTALS a wide variety of uses in displays, and an important example of lyotropic LCs is cell membranes formed by amphiphilic lipids. Surfactants in water (i.e., soap water) constitute another useful example of lyotropic LCs. Although the majority of LCs are organic molecules, there exist many LC materials incorporating metals into organic anisotropic molecules [1-3]. These organic-inorganic hybrid LC materials are described as metallomesogens and are recently called metallotropic LCs [4] as distinguished from two main LC classes. In fact, metallomesogens can be classified as either thermotropic or lyotropic LCs depending on their composition and conditions. However, it should be noted that metallomesogens offer a material platform to incorporate magnetic, electronic, optical, redox, and catalytic properties common to inorganic materials into LCs.Although thermotropic LCs have been known to scientists for over 100 years since a discovery by the Austrian botanical physiologist Friedrich Reintizer in 1888, it was only in the late 1960s that they began to be used in display applications. Today, they are best known for their exceptionally successful commercial applications in flat panel display products such as TVs, smart phones, computer displays, and digital projectors. Although today's LC display technology is becoming very advanced, LC materials used in display devices possess the simplest nematic (N) phase and their molecules have been variants on simple rod shapes (Fig. 6.1a). Besides nematic phases, LCs can exhibit other phases: smectic (Sm), columnar (Col), and cubic phases, depending on the orientational or positional orders of their molecules. Nematic phases have only long-range orientational order, smectic mesophases exhibit one-dimensional (1D) positional order and form two-dimensional (2D) layered ...

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“…[16][17][18] Nevertheless, the new mesophases were still discovered, which confirms the validity of the data about the novel banana-shaped molecules. [19,20] Therefore, the main aim of modern liquid crystals research is designing new materials characterised by the rich polymorphism. [21,22] By introducing various linking groups [23] (like azo, Schiff bases, [24] thioester [25] and ester [26,27]), we can influence the type of the mesophase.…”

Section: Introductionmentioning

confidence: 99%

The kinetics of the E-Z-E isomerisation and liquid-crystalline properties of selected azobenzene derivatives investigated by the prism of the ester group inversion

et al. 2015

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Two new groups of azobenzene ester derivatives were synthesised: alkyl 4-[4-(nonyloxy)phenyl]diazenyl]benzoates and 4-[4-(nonyloxy)phenyl]diazenyl]phenyl alkanoates. All 35 presented homologues are mesogenic. Moreover, some of the above-mentioned compounds exhibit rich liquid-crystalline polymorphism likewise tetramorphism. During this investigation by the use of polarising optical microscopy, differential scanning calorimetry and X-Ray studies, six types of mesophases were detected: nematic, smectics (A, C, I, F) and G. Furthermore, due to the presence of the photosensitive azo moiety, the E-Z isomerisation reaction is possible. This process, which is initiated by the UV irradiation, causes significant changes in the UV-Vis absorption spectra of investigated compounds. However, the photoisomerisation is a reversible process and in the dark the thermal relaxation of Z isomer takes place. Based on the achieved data, the kinetic constants of the isomerisation and relaxation processes were calculated. It shows that conversion of the ester bond makes some changes in the optical properties. The shift of about 7 nm of the absorbance maximum was observed. Surprisingly, the inversion of the ester group has significant influence on the liquid-crystalline polymorphism replacing one mesophase (for benzoates) into four (for alkanoates).

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Mesomorphic behaviour of 1,3-phenylene bis[4-(4-alkoxyphenyliminomethyl)benzoates] and related compounds

Cited by 103 publications

References 14 publications

Supramolecular ferroelectrics

Supramolecular ferroelectrics

Electric‐ and Light‐Responsive Bent‐Core Liquid Crystals: From Molecular Architecture and Supramolecular Nanostructures to Applications

The kinetics of the E-Z-E isomerisation and liquid-crystalline properties of selected azobenzene derivatives investigated by the prism of the ester group inversion

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