posted on 2017-02-15, 17:48authored byRyota Matsuoka, Ryota Sakamoto, Ken Hoshiko, Sono Sasaki, Hiroyasu Masunaga, Kosuke Nagashio, Hiroshi Nishihara
Synthetic two-dimensional
polymers, or bottom-up nanosheets, are
ultrathin polymeric frameworks with in-plane periodicity. They can
be synthesized in a direct, bottom-up fashion using atomic, ionic,
or molecular components. However, few are based on carbon–carbon
bond formation, which means that there is a potential new field of
investigation into these fundamentally important chemical bonds. Here,
we describe the bottom-up synthesis of all-carbon, π-conjugated
graphdiyne nanosheets. A liquid/liquid interfacial protocol involves
layering a dichloromethane solution of hexaethynylbenzene on an aqueous
layer containing a copper catalyst at room temperature. A multilayer
graphdiyne (thickness, 24 nm; domain size, >25 μm) emerges
through
a successive alkyne–alkyne homocoupling reaction at the interface.
A gas/liquid interfacial synthesis is more successful. Sprinkling
a very small amount of hexaethynylbenzene in a mixture of dichloromethane
and toluene onto the surface of the aqueous phase at room temperature
generated single-crystalline graphdiyne nanosheets, which feature
regular hexagonal domains, a lower degree of oxygenation, and uniform
thickness (3.0 nm) and lateral size (1.5 μm).