A re-examination of claims of aminoferrocene–graphene-based molecular magnets

Abstract

A recent investigation claimed that graphene oxide (GO) modified by aminoferrocene gave a material that showed room temperature colossal superparamagnetic behavior. The first step in the reported synthesis of aminoferrocene was the direct nitration of ferrocene. We show here, in accord with previous precedents, that the direct nitration of ferrocene by the nitronium ion does not occur under the conditions reported and, therefore, the material described previously cannot be based on aminoferrocene. Computational investigations undertaken herein show that the model used to account for the magnetic properties of the material results from an artifact of the GO model employed.