Liquid‐Crystalline Mixed [5 : 1]Hexa‐adducts of [60]Fullerene. Preliminary Communication

Abstract

A liquid-crystalline mixed [5 : 1]hexa-adduct of [60]fullerene was synthesized by addition of two different malonate derivatives onto C 60 . The hexa-adduct derivative 2 was prepared by a stepwise synthetic procedure (fullerene ! mono-adduct of C 60 ! hexa-adduct of C 60 ). Cyanobiphenyl and octyloxybiphenyl derivatives were selected as mesogens. The malonate derivatives showed either a monotropic nematic phase or a monotropic smectic A phase, and the hexa-adduct derivative gave rise to an enantiotropic smectic A phase. The versatile chemistry of C 60 prompted us to design liquid-crystalline hexa-adducts to explore the behavior of mesogens in a spherical environment. The first hexa-adduct of C 60 was synthesized previously from malonate 1 (see Scheme below), which gave rise to a smectic A phase [2c]. Recently, we described a chiral hexa-adduct of C 60 , which was prepared from a laterally-branched optically active mesogen. A chiral nematic phase was observed [2m]. Besides our work, other mesomorphic hexa-adducts of C 60 were reported. Diederich and co-workers described a hexa-adduct containing eight Et groups and four mesogenic cyanobiphenyl units. This compound afforded a nematic phase during the first heating run [3]. Felder-Flesch et al. reported two hexa-adducts of C 60 containing either twelve mesogenic cholesterol units, or ten mesogenic cholesterol units and two non-mesogenic groups. Both compounds showed a smectic A phase [6]. In all the above-mentioned cases, the observed liquid-crystalline properties are in

Synthesis of highly functionalized C60 fullerene derivatives and their applications in material and life sciences

“…[90][91][92] Scheme 31 Synthetic route to [5:1] fullerene hexakis-adduct. [90][91][92] Scheme 31 Synthetic route to [5:1] fullerene hexakis-adduct.…”

Conformational Preferences and the Phase Stability of Fullerene Hexa‐adducts

“…The development of fullerene chemistry facilitates the functionalization of [60‐ I h ]‐fullerene (C 60 ), and made the functionalized C 60 derivatives an important building block of many novel molecular systems . Functional materials like amphiphilic fullerene hexa‐adducts (FHAs),, photoactive FHAs, electroactive FHAs, bioactive FHAs, giant surfactants, and semiconducting giant molecules have been synthesized, and unique supramolecular assembles, including helical supramolecular columns, supramolecular double cables, smectic A phase,, chiral nematic phase,, micelles, and vesicles, were observed among these molecules. The conformation of the C 60 ‐based molecules is essential to its self‐organization behaviors and its material properties because conformational changes can affect the distances among the peripheral functional groups and molecular shapes.…”

Fullerene‐Containing Liquid Crystals

“…More recently, Deschenaux and collaborators [52] synthesized a mixed (5 : 1) hexakisadduct as the addition of two mesogens (or more in case of other addition patterns) onto C 60 could be an elegant means for the design of fullerenecontaining liquid crystals with tailored properties. In this first example, they selected cyanobiphenyl and octyloxybiphenyl derivatives as mesomorphic promoters to prepare hexakisadduct 48 (Figure 6.26).…”