FT-IR and FT-Raman Spectroscopic Studies of 1-(p-n-Alkyl Phenyl) 3-(p-n-Alkyloxyphenyl) Propane 1,3-Diones
01 Jul 2001-Molecular Crystals and Liquid Crystals (Taylor & Francis Group)-Vol. 363, Iss: 1, pp 19-34
TL;DR: In this paper, the FT-IR and FT-Raman spectroscopic studies of mesogens with the general molecular formula 1-(p-n-alkyl phenyl) 3-(p nalkyloxyphenyl) propane 1,3-diones having alkyl chain lengths C10, C11 and C12 are carried out.
Abstract: FT-IR and FT-Raman spectroscopic studies of the mesogens with the general molecular formula 1-(p-n-alkyl phenyl) 3-(p-n-alkyloxyphenyl) propane 1,3-diones having alkyl chain lengths C10, C11 and C12 are carried out. An analysis of the vibrational spectra of C10, C11 and C12 at room temperature strongly suggests that while C12 probably belongs to a highly ordered monoclinic or orthorhombic type of lattice, C10 and C11 belong to a hexagonal or triclinic unit cell, having lesser degree of lattice order.
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TL;DR: Metallomesogens, metal complexes of organic ligands which exhibit liquid crystalline (mesomorphic) character, combine the variety and range of metal-based coordination chemistry with the extraordinary physical properties exhibited by liquid crystals as discussed by the authors.
Abstract: Metallomesogens, metal complexes of organic ligands which exhibit liquid crystalline (mesomorphic) character, combine the variety and range of metal-based coordination chemistry with the extraordinary physical properties exhibited by liquid crystals Thermotropic metallomesogens have been made incorporating many metals, including representatives of s-, p-, d-and even f-block elements Both rodlike (calamitic) and disklike (discotic) thermotropic metallomesogens are known, and examples of all the main mesophase types are found Many different varieties of ligand can be used: monodentate (4-substituted pyridines), bidentate (β-diketonates, dithiolenes, carboxylates, cyclometalated aromatic amines), or polydentate (phthalocyanines, porphyrins) As with organic mesogens, molecular shape and intermolecular forces play an important role, ie the ligands are important in determining mesophase character The chief requirement for a metallomesogen is a rigid core, usually unsaturated and either rod- or disklike in shape, bearing several long hydrocarbon tails The metal atom is usually at or near the center of gravity of the molecule In some cases the ligands are themselves mesogenic, but this is not a requirement The presence of one or more metals opens many exciting possibilities: new shapes, not easily generated by organic compounds, and hence new properties are then accessible The incorporation of d-block metals brings with it features such as color and paramagnetism Profound effects arise from the large and polarizable concentration of electron density that every metal atom possesses, since the molecular polarizability is a key factor in determining whether a molecule will form liquid crystals Enhanced physical properties (eg high birefringencies), as well as new and unexpected ones, will result A major requirement for metallomesogens to find applications in new device technology is that the metal–ligand bonds are strong and inert and the complexes stable; this can be accomplished with, for example, chelating ligands and the 5d metals
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