Wednesday, December 5, 2012

Functional Graphenic Materials Via a Johnson−Claisen Rearrangement

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.

No comments:

Post a Comment