traditional way, where C 60 was linked together with large liquid crystal mesogens
to give nematic, cholesteric, smectic, and columnar phases of LCs by the Bingel
reaction or the 1,3-dipolar cycloaddition reaction. This strategy needs large
mesogens to fulfill the molecular aspect ratio of LCs. Thus the content of C 60 is
low, usually less than 20%, and the properties from fullerene are hindered.
Another approach is via the supramolecular self-assembly, where the [60]fullerene derivatives self-assemble to form supramolecular structure which meets the
aspect ratio requirements of liquid crystals. The supramolecular LC approach
opens up new strategies to design liquid crystals with low molecular aspect ratio,
enabling high [60]fullerene content in the supramolecular LCs. Some of the
interesting properties form [60]fullerene LCs are also summarized, especially
the electrochemical properties, the chiral properties, the light emitting properties,
and the optoelectronic properties. Among them, high fullerene content is the key
for these LCs to achieve good properties.
Keywords
Fullerene · Liquid crystal · Supramolecular chemistry · Self-organization
Definition
[60]Fullerene-based liquid crystals are a new kind of materials with excellent
electro-optical properties of fullerenes and self-organization and processible properties of liquid crystals. The design of fullerene liquid crystals includes two ways:
direct synthesis of molecular liquid crystals with the molecular aspect ratio meeting
the requirement for liquid crystals and supramolecular liquid crystals with the
supramolecular structure meeting the aspect ratio requirement of liquid crystals
through self-assembly or self-organization of fullerene derivatives. This entry will
focus on the design method of [60]fullerene liquid crystals from molecular structure
aspect. Functional groups such as ferrocene, dendron, chiral, and phthalocyanine can
be introduced into fullerene-based liquid crystals by careful molecular design, which
expands the application field of fullerene-based liquid crystals.
Introduction
General Description of [60]Fullerenes
[60]Fullerene (C 60 ), the most familiar member in fullerene’s family, is a truncated
icosahedron (I h ) with 60 vertices and 32 faces (20 hexagons and 12 pentagons where
no pentagons share a vertex) consisting of sp
2 -hybridized carbon atoms, as shown in
Fig. 1. The van der Waals diameter of a C 60 molecule is 1.01 nanometer (nm), while
the nucleus to nucleus diameter of a C 60 molecule is 0.71 nm. The C 60 molecule has
two bond lengths. The 6:6 ring bonds (between two hexagons) can be considered as
150
X. Yang et al.
to give nematic, cholesteric, smectic, and columnar phases of LCs by the Bingel
reaction or the 1,3-dipolar cycloaddition reaction. This strategy needs large
mesogens to fulfill the molecular aspect ratio of LCs. Thus the content of C 60 is
low, usually less than 20%, and the properties from fullerene are hindered.
Another approach is via the supramolecular self-assembly, where the [60]fullerene derivatives self-assemble to form supramolecular structure which meets the
aspect ratio requirements of liquid crystals. The supramolecular LC approach
opens up new strategies to design liquid crystals with low molecular aspect ratio,
enabling high [60]fullerene content in the supramolecular LCs. Some of the
interesting properties form [60]fullerene LCs are also summarized, especially
the electrochemical properties, the chiral properties, the light emitting properties,
and the optoelectronic properties. Among them, high fullerene content is the key
for these LCs to achieve good properties.
Keywords
Fullerene · Liquid crystal · Supramolecular chemistry · Self-organization
Definition
[60]Fullerene-based liquid crystals are a new kind of materials with excellent
electro-optical properties of fullerenes and self-organization and processible properties of liquid crystals. The design of fullerene liquid crystals includes two ways:
direct synthesis of molecular liquid crystals with the molecular aspect ratio meeting
the requirement for liquid crystals and supramolecular liquid crystals with the
supramolecular structure meeting the aspect ratio requirement of liquid crystals
through self-assembly or self-organization of fullerene derivatives. This entry will
focus on the design method of [60]fullerene liquid crystals from molecular structure
aspect. Functional groups such as ferrocene, dendron, chiral, and phthalocyanine can
be introduced into fullerene-based liquid crystals by careful molecular design, which
expands the application field of fullerene-based liquid crystals.
Introduction
General Description of [60]Fullerenes
[60]Fullerene (C 60 ), the most familiar member in fullerene’s family, is a truncated
icosahedron (I h ) with 60 vertices and 32 faces (20 hexagons and 12 pentagons where
no pentagons share a vertex) consisting of sp
2 -hybridized carbon atoms, as shown in
Fig. 1. The van der Waals diameter of a C 60 molecule is 1.01 nanometer (nm), while
the nucleus to nucleus diameter of a C 60 molecule is 0.71 nm. The C 60 molecule has
two bond lengths. The 6:6 ring bonds (between two hexagons) can be considered as
150
X. Yang et al.