It should be mentioned that we have also synthesized perfectly defined
organometal complexes such as 45 as catalysts for oxygen reduction [283]. They
function as catalysts in their own right, but also serve as model systems to optimize
the desired four-electron transfer in oxygen reduction in pyrolytically formed
materials (Fig. 14).
9 Conclusion
What this brief excursion into cruder methods of graphene formation tells us is that
the need to obtain a desired material function must be carefully weighed against the
synthetic effort required to make the requisite material. This balance is the essence
Fig. 13 Nitrogen-doped graphene as metal-free catalyst for oxygen reduction (Reproduced from
reference 278 with permission from Angew. Chem. Int. Ed. and John Wiley and Sons)
Fig. 14 Trinuclear organometal complex 45 and representation of 45 as catalyst for oxygen reduction
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K. Mu ¨llen