In spirit of one of Jeremiah's "favorites":
Graphene oxide (GO) is modified using the Johnson-Claisen rearrangement,
an improvement over the group's previously reported GO
functionalization methods. By utilizing triethyl orthoacetate (TEOA) as reagent and solvent, the rearrangement installs
carbon bonded reactive ester functionalities that are not affected by
further reduction of the GO to its more conductive counterpart,
Graphene. The ester-functionalized GO was then reduced using sodium
borohydride. After reduction, treatment with oxalyl chloride and
subsequent reaction with various amines creates amide functionalized
graphenes with various properties. By installing propargyl groups, they
make a "clickable" graphene surface. Furthermore, by using a sulfonated
azide tag, they are able to assess the degree of functionalization by
XPS. In an alternate demonstration of the use of their method, they
synthesize cationic and anionic graphene derivatives and assemble them
in a layer by layer fashion to create graphene sheets up to 12 layers
thick.
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