Syntheses and Physical Properties of Ferrocene Derivatives (XI)

The molecular and crystal structure of one of the monosubstituted ferrocene derivatives which has been discussed from a view point of liquid crystallinity, ω[4-(4-methoxyphenoxycarbonyl)-phenoxycarbonyl]ethyl 4-ferrocenylbenzoate, was determined by the X-ray diffraction method. This compound had the ‒C2H4‒ chain located between the phenylferrocenyl group and the mesogenic one. The ‒C2H4‒ chain unit as a flexible spacer was an all-trans conformation. The molecule was slightly bent around the ester group to the ferrocenylbenzoate in order to form a rod-like structure. Two cyclopentadienyl rings in the ferrocenyl group exhibited an eclipsed conformation rather than a staggered one. In this crystal, the molecules constructed a layer structure just like the smectic one of the liquid crystals. The molecular and crystal structure was quite similar to those of other homologues showing liquid crystallinity in this series. This compound, however, did not exhibit a liquid crystalline phase.