title: Definitive proof of graphene hydrogenation by Clemmensen reduction: use of deuterium labeling.
abstract: Graphane is one of the most intensively studied derivatives of graphene. Here we demonstrate the evaluation of exact degree of graphene hydrogenation using the Clemmensen reduction reaction and deuterium labeling. The Clemmensen reduction reaction is based on application of zinc in an acid environment. It effectively reduces various functional groups (like ketones) present in graphite oxide. However, the mechanism of reduction is still unknown and elusive. Here we bring a major insight into the mechanisms of the Clemmensen reduction via deuterium labeling and the topochemical approach applied on graphite oxide. The use of deuterated reactants and the exact measurement of deuterium concentration in reduced/hydrogenated graphene by nuclear methods can be used for accurate estimation of C-H bond abundance in graphene. Various topochemical configurations of experiments showed that the reduction of a ketonic group proceeds in contact with the zinc metal by a carbenoid mechanism. Our results showed that the application of nuclear methods of isotope analysis in combination with deuterium labeling represents a very effective tool for investigation of graphene based materials. Our results demonstrate that graphene based materials can also be effectively used for the investigation of organic reaction mechanisms, because the robust structure of graphene allows the use of various spectroscopic techniques which could not be applied on small organic molecules.
authors.affiliation: Department of Inorganic Chemistry, University of Chemistry and Technology, Prague 166 28 Prague 6, Czech Republic. zdenek.sofer@vscht.cz.
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Sofer
authors.forename: Ondřej
authors.initials: O
authors.lastname: Jankovský
authors.forename: Alena
authors.initials: A
authors.lastname: Libánská
authors.forename: Petr
authors.initials: P
authors.lastname: Šimek
authors.forename: Michal
authors.initials: M
authors.lastname: Nováček
authors.forename: David
authors.initials: D
authors.lastname: Sedmidubský
authors.forename: Anna
authors.initials: A
authors.lastname: Macková
authors.forename: Romana
authors.initials: R
authors.lastname: Mikšová
authors.forename: Martin
authors.initials: M
authors.lastname: Pumera