Synthesis And Properties Of Star-shaped Schiff Base Crystal Compounds Containing Silicon

Star-shaped crystal having a plurality of silicon-containing Schiff base is different fromthe good performance of the conventional liquid crystal, and both characteristics of anisotropyof liquid crystal molecules, and an organic silicon compound having the anti-aging, electricalinsulation properties. This design not reported synthesis of6kinds of Schiff base-type siliconas the center of the star type liquid crystal compound, a composition containing both asufficient rigidity, and a soft segment containing a suitable, this structure will not only reducethe melting point of the liquid crystal compound lower than the thermal decompositiontemperature, but also a stable liquid crystalline state was observed. Using infraredspectroscopy synthesized products were confirmed structure and analyzed by thermalpolarized optical microscopy and differential scanning calorimetry of liquid crystallinebehavior of the product.1. Synthesis of Schiff base compounds, and then replace the ethanol reacts with chlorineoccurred last received the synthesis of new compounds on the LCD Methyltrichlorosilane. Byinfrared spectroscopy to characterize the structure of the liquid crystal compounds, liquidcrystal properties of differential scanning calorimetry and thermal polarized opticalmicroscopy testing of the target product. The results showed that: the terminal group is a nitrocompound of the star becomes a liquid crystal phase range180℃~223℃, flaky, rod-shapedsmectic liquid crystal texture; sulfonic acid end groups is a liquid crystal compoundphase-change star in the range of208℃~253℃, there smectic liquid crystal phase flakytexture; terminal methyl group of the star-shaped liquid crystal compound phase-changeranges191℃~223℃, the emergence of the liquid crystal smectic phase woven sheet structure.Star compounds were3a,3b,3c are a smectic liquid crystal.2. Synthesis of Schiff base compounds, hydroxy acid and chlorine will then ethanol wassynthesized by replacing4-(ω)-hydroxyethoxy acid, then received Methyltrichlorosilane Finally, with Schiff base compounds by ester Synthesis of a new liquid crystal compound, aliquid crystal structure by infrared spectroscopy compounds were characterized by differentialscanning calorimetry and polarized optical microscopy in different series of products of theliquid crystal properties. The results showed that: the compound5a star appeared smecticliquid crystal texture of a sheet in a149℃~243℃two temperature ranges; Compound5b starcone appears in the temperature range151℃~174℃~249℃of shape, two schlieren textureof the nematic phase; Star compound5c temperature change process165℃~254℃alsoappeared in a tapered shape, the two schlieren texture of the nematic phase, star compound5a,5b,5c, respectively smectic liquid crystal, nematic liquid crystal and a nematic liquid crystal.It has shown that: changes in the terminal groups of the molecule crystal may have someeffect type liquid crystal compound, and it will affect the texture information on the LCD; thephase transition temperature of the polar end groups of the type of interaction, hydrogen bond,the three spatial effect; Star LCD liquid crystal polar end group phase change material polarityinterval smaller than the width of the end groups, primitive longer, wider range of liquidcrystal phase transition.