A mixed fullerene-ferrocene thermotropic liquid crystal: synthesis, liquid-crystalline properties, supramolecular organization and photoinduced electron transfer

Grafting of a ferrocene-contg. liq.-cryst. malonate deriv. to C60 led to the mixed fullerene - ferrocene material 1 which gave rise to a smectic A phase. Cholesterol was used as liq.-cryst. promoter. X-ray diffraction expts. and volumetric measurements indicated that 1 is organized in double layered structures. The corresponding supramol. organization within the mesomorphic lamellar phase was characterized by a microsegregation of the different units (ferrocene, fullerene, and cholesterol) in distinct sublayers. In such a smectic A phase, C60 imposes the arrangement of the other mol. moieties. Photophys. studies revealed that electron transfer occurs from the donor ferrocene to the electron accepting fullerene. The formation of a long-lived radical pair, with lifetimes of the order of several hundred nanoseconds, was confirmed by time-resolved spectrometry, esp. in the near IR region, in which the radical anion of the fullerene moiety displays its characteristic fingerprint absorption. [on SciFinder(R)]