Herein, we studied [2 + 2] and [4 + 2] cycloaddition reactions between maleimides and free-standing graphene, epitaxial graphene, and graphene deposited over hydrogen terminated SiC. These reactions are strongly endergonic with a ΔGtoluene°298 close to 73 kcal/mol.
The inclusion of solvent effects revealed that the reaction became even less favorable in condensed phase as compared with the gas phase process. For epitaxial graphene or graphene deposited on top of hydrogen terminated SiC, we found that the substrate has a small influence over the cycloaddition reaction energies. In effect, they were strongly endergonic much like the case of free-standing graphene. Although the fluorinated maleimides used in recent experiments proved to be more reactive than tetracyanoethylene and maleic anhydride, their cycloaddition reactions with graphene are still strongly endergonic. However, our calculations indicated that these reactions are more likely to occur on the buffer layer of epitaxial graphene.
Read full article at: http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.7b03413
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