Novel synthetic pathways towards well-defined double-layered nanographene
derivatives
Silvia Bartoccini,
1
Assunta Marrocchi,
2
Henning Hopf
1
1
Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany
2
Università degli Studi di Perugia, via Elce di Sotto 8, I-06132 Perugia, Italy
Graphene has been extensively investigated since its first isolation in 2004, which was based on
repeated peeling of highly oriented pyrolyzed graphite.
[1]
The unique electronic, thermal, and
mechanical properties of this system make it a promising candidate for applications in
electronics, energy storage and conversion, sensing, catalysis, biological labeling.
[2]
However, a
number of challenges remain for the implementation of graphene in electronic devices.
[3]
The
current major issue is the lack of an efficient way to reliably produce high-quality graphene in
large quantities.
[4]
Another difficulty lies in the lack of a controllable synthesis of graphene with
defined size, shape, and edge structure, which is crucial to widen the energy band gap of
graphene thereby enabling its use as an active material in field-effect transistors.
[5]
Two strategies have been established for graphene synthesis: exfoliating graphite towards
graphene (top-down) and building up graphene from molecular building blocks (bottom-up). This
latter seems to offer a significant opportunity to tune the molecular size, shape, edge, and
composition of graphenes but unfortunately planarizing large precursors reaches its limit in
solution,
[2]
which is primarily caused by their poor solubility. In addition, the exact structural
characterization of the products become increasingly difficult given the strong aggregation and
profound insolubility of the giant graphene molecules. On the basis of current encouraging
results, directing future investigations toward novel strategies to overcome the above mentioned
issues is needed.
Our research project is focused on the preparation of novel structurally well-defined double-
layered nanographene derivatives, with the aim of developing new protocols for the controlled
synthesis of graphene material. The research idea comes from some considerations regarding
[2.2]paracyclophane-based systems, which have been extensively investigated for many years by
us. [2.2]Paracyclophane has proven to be a valuable building block in a very large number of
synthetic processes, especially for the creation of structures with extended
-systems.
[6]
Here we present that [2.2]paracyclophane holds the promise of accessing nanographene dimers
featuring different or identical space orientation of the two constituting layers (Figure 1), which
could lead to different optical and electrical properties, due to the possible variation of the
HOMO-LUMO energy gap.
Figure 1
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PS1 4
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