Ferrocene derivatives, metallomesogens

In 1976 Malthete and Billard [10] reported ferrocene derivatives, 2, which were the first well characterized organotransition metallomesogens. 

The research on ferrocene-containing thermotropic liquid crystals has concentrated, so far, on design, synthesis, and investigations of thermal properties. These efforts, and more particularly the results obtained, could be a source of inspiration for the development of new metallomesogens. As an example, we recently reported the first liquid crystalline ruthenocene derivatives [29]. 

Recent progress in material science, notably with the development of new materials exhibiting blue phases, has generated a renewed interest in the incorporation of the functional properties with the unique structure of frustrated phases. Synthesis of a monosubstituted ferrocene-based chiral Schiff s base derivative which exhibits TGBA and blue phases has been reported [17] (Fig. 9). Other metallomesogens leading to blue phases have been found for palladium complexes [18] (Fig. 10). Optically active materials incorporating... 

Ferrocene (Fc) possesses a rich synthetic chemistry, a three-dimensional structure which allows the preparation of many derivatives, high thermal stability, and good solubility in common organic solvents. These characteristics allow the synthesis of a great variety of liquid-crystalline materials. Furthermore, its unique electrochemical properties (fast and reversible one-electron transfer process) make Fc a valuable building block for the elaboration of redox-active supramolecular switches. In 30 years (1976-2006), liquid-crystalline ferrocenes have been established as a versatile class of metallomesogens. The aim of this chapter is to highlight the main results obtained for... 

For many years, the only examples of formally six-coordinate metal complexes forming lamellar mesophases were derivatives of ferrocene, while the vast majority of calamitic metallomesogens were based essentially on two- and four-coordinate complexes of metals from groups 8 and 10. Novel metallomesogens based on high coordination number metal centres were recently reported to show nematic and lamellar mesophases. 

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