Lanthanidomesogens

Liquid crystals (LCs) are a state of matter between liquid and solid and the corresponding compounds present at least two melting points, the first corresponding to the transition to the LC cloudy phase and the second being a clarification to pure liquid. Some LCs are seen in living systems; for instance, certain proteins and cell membranes are LCs. Technically, the properties of LCs are exploited in electronic displays (LCDs). Lanthanidomesogens can be defined as liquid-crystalline lanthanide complexes or lanthanide-containing LCs. These compounds combine the unique properties of lanthanide ions, luminescence and paramagnetism, with those of LCs: fluidity, anisotropy, and response to electric and magnetic fields. Lanthanidomesogens allow obtaining materials that emit linearly polarized light or that can be aligned by an external magnetic field. The reader is first introduced to the different types of mesophases and to the experimental methods used for identifying them. A detailed presentation of the different classes of lanthanidomesogens is then given, with the focus on their structural, luminescent, magnetic, and electric properties. The classes of compounds reviewed include Schiff’s base complexes, beta-enaminoketonates, beta-diketonates, bis(benzimidazolyl)pyridine complexes, phthalocyanine complexes, porphyrin complexes, lanthanide alkanoates, polyoxometalate-surfactant complexes, ionic liquid-crystalline lanthanide complexes, and lyotropic lanthanidomesogens. The chapter concludes with an overview of the less-documented actinide-containing LCs (actinidomesogens).status: publishe