Liquid crystal salts

The following liquid crystal salts can be readily prepared in small or large quantities ... 

Independently, Ishida et al. found the enantioselective photocycloaddition of (243) using an enantiopure amphiphlic amine as metastable liquid crystal salt. Irradiation of the liquid crystal salt of an enantiopure amine with a photoactive acid (45 °C (annealing time < 1 min) enantioselectively afforded the anti (-l-)photodimer (+86% ee). In contrast, irradiation of an aged sample, isothermally annealed for 20 h, gave the anti (—)photodimer (—94% ee). °... 

Substitution of chloropolymer is possible using a variety of nucleophiles. The most common are sodium salts of alcohols and phenols. Thermoplastics are obtained using a single substituent, whereas multiple substituents of sufficiently different size lead to elastomers (2). Liquid crystal behavior similar to polysHoxanes has been noted in most homopolymers. The homopolymer formed using trifluoroethanol as a substituent has received a fair amount of academic scmtiny (7). 

Martin [25] has also shown that ammonium salts display similar behavior. [Cetyltrimethylammonium]2[ZnCl4], for example, first melts to an Sc-type liquid crystal at 70 °C and then to an S -type mesophase at 160 °C. The broad diffraction features observed in the liquid-crystalline phases are similar to those seen in the original crystal phase and show the retention on melting of some of the order originating from the initial crystal, as shown in Figure 4.1-6. 

Structured laundry liquids are currently available in Europe and were recently introduced in the United States [50,51]. These products typically contain high levels of surfactants and builder salts, as well as enzymes and other additives. In the presence of high ionic strength, the combination of certain anionic and nonionic surfactants form lamellar liquid crystals. Under the microscope (electron microscope, freeze fracturing) these appear as round droplets with an onion-like, multilayered structure. Formation of these droplets or sperulites permits the incorporation of high levels of surfactants and builders in a pourable liquid form. Stability of the dispersion is enhanced by the addition of polymers that absorb onto the droplet surface to reduce aggregation. 

Typically the formulation may contain up to 60% active with builder salts and a water level of about 30-40% [52]. The weight ratio of LAS/AE may range from 1.5 1 up to 4 1. The combination of LAS and AE is especially effective for two reasons. First, LAS and AE interact strongly to form the lamellar phase liquid crystals. Second, both ingredients can be introduced into the liquid formulation as a 95 + % active liquid to control the amount of water going into the formulation. LAS can be introduced into the formulation as sulfonic acid and neutralized in situ. 

The synthesis of the N03 and PFg salts of the iron(III) complex of the terdentate phenolate anion of the liquid crystal Schiff base (7) provides the first example of the coexistence of spin transition and liquid crystal properties in a single compound. The ligand now needs to be tuned to increase the spin cross-over transition temperature and decrease the transition temperature to the liquid crystal state. ... 

Advances in the chemistry of [M(CN)5L]" complexes, for M = Fe, Ru, and Os, have been reviewed.There has been rather little activity in the preparation of novel complexes, but considerable activity in studying the properties, especially solvatochromism and various aspects of kinetics of substitution, of known complexes. However there has been an attempted preparation of [Fe(CN)5(Ci2H25NH2)], in the hope of generating micelles or lyotropic liquid crystals. This preparation appeared to yield [Fe(CN)4(H20)(Ci2H25NH2)], whose alkali metal salts gave a hexagonal mesophase in water, but were also readily hydrolyzed to [Fe(CN)4(H20)2] . Heterobinuclear complexes of the form [(NC)5FeL ML 5] " " have been much studied, especially in relation to intramolecular electron transfer (see Section 5.4.2.2.5). 

Note 4 Cubic mesophases have long been known in thermotropic salt-like compounds and in lyotropic liquid-crystals. 

These structures are extensively described in the current literature (Fanum, 2008 Friberg, 1976 Birdi, 2002 Holmberg, 2004 Somasundaran, 2006). Even within the same phases, their self-assembled structures are tunable by the concentration for example, in lamellar phases, the layer distances increase with the solvent volume. Lamellar structures are found in systems such as the common hand soap, which consists of ca. 0% soap + 20% water. The layers of soap molecules are separated by a region of water (including, salts etc.) as a kind of sandwich. The x-ray diffraction analysis shows this structure very clearly. Since lyotropic liquid crystals rely on a subtle balance of intermolecular interactions, it is more difficult to analyze their structures and properties than those of thermotropic liquid crystals. Similar phases and characteristics can be observed in immiscible diblock copolymers. 

The addition of salts to micelles gives large micelles that turn into cylindrical shapes. However, the addition of cosurfactant produces the liquid crystal phase. As a consequence, these micellar systems with added cosurfactant are found to undergo several macroscopic phase transitions in dilute solutions. These transitions are as follows ... 

The metal dissolves in dilute and concentrated mineral acids. Evaporation crystallizes salts. At ordinary temperatures, ytterbium, similar to other rare earth metals, is corroded slowly by caustic alkalies, ammonium hydroxide, and sodium nitrate solutions. The metal dissolves in liquid ammonia forming a deep blue solution. 

When mesophase, that is, liquid crystal, consisting of three components of bile salt, lecithin and cholesterol was produced, deposition of calcium salts of bile acids was observed on the cholesterol disk surface. The relation between mesophase formation and calcification will be elucidated in this paper. 

Cordon, C.M. et al., Ionic liquid crystals hexafluorophosphate salts, /. Mater. Chem., 8, 2627, 1998. 

Figure 12.19 Conceptual structure of ionic salt crystals and liquids a = crystal, b and c = liquid crystals, d = liquid, e = ionic liquid, according to the model of Hamaguchi and Ozawa. (Adapted from Hamaguchi, H., and Ozawa, R., Adv. Chem. Phys., 131,85-104, 2005. With permission.)...

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