Functional Graphenic Materials Via a Johnson-Claisen Rearrangement.

TitleFunctional Graphenic Materials Via a Johnson-Claisen Rearrangement.
Publication TypeJournal Article
Year of Publication2013
AuthorsSydlik, SA, Swager, TM
JournalAdvanced Functional Materials
Keywordsgraphene oxide surface group redn Johnson Claisen

The hydroxyl functionalities in graphene oxide (GO), the vast majority that must be allylic alcs., have been subjected to Johnson-Claisen rearrangement conditions. Under these conditions, a [3, 3] sigmatropic rearrangement after reaction with tri-Et orthoacetate gives rise to an ester functional group, attached to the graphitic framework via a robust C-C bond. This variation of the Claisen rearrangement offers an unprecedented versatility of further functionalizations, while maintaining the desirable properties of unfunctionalized graphene. The resultant functional groups were found to withstand reductive treatments for the deoxygenation of graphene sheets and a resumption of electronic cond. is obsd. The ester groups are easily sapond. to carboxylic acids in situ with basic conditions, to give water-sol. graphene. The ester functionality can be further reacted as is, or the carboxylic acid can easily be converted to the more reactive acid chloride. Subsequent amide formation yields up to 1 amide in 15 graphene carbons and increases intergallery spacing up to 12.8 \AA, suggesting utility of this material in capacitors and in gas storage. Other functionalization schemes, which include the installation of terminal alkynes and dipolar cycloaddns., allow for the synthesis of a highly pos. charged, water-sol. graphene. The highly neg. and pos. charged graphenes (zeta potentials of -75 mV and +56 mV, resp.), are successfully used to build layer-by-layer (LBL) constructs. [on SciFinder(R)]