  We present an environmentally benign methodology for the covalent
functionalization (arylation) of reduced graphene oxide (rGO) nanosheets with
arylazo sulfones. A variety of tagged aryl units were conveniently accommodated
at the rGO surface via visible light irradiation of suspensions of carbon
nanostructured materials in aqueous media. Mild reaction conditions, absence of
photosensitizers, functional group tolerance and high atomic fractions (XPS
analysis) represent some of the salient features characterizing the present
methodology. Control experiments for the mechanistic elucidation (Raman
analysis) and chemical nanomanipulation of the tagged rGO surfaces are also
reported.
