The reactions of mass-selected iron clusters Fe n + (n=1-5) with dimethyl carbonate, (CH 3 O) 2 CO, are examined by means of Fourier-transform ion-cyclotron-resonance mass spectrometry. For the bare metal cation Fe + , loss of a methyl radical prevails which leads to the iron carbonate species FeOC(O)OCH 3 + . For the corresponding Fe n + clusters, this type of reaction is not observed anymore. Instead, the clusters show a strong tendency for a formal O-atom abstraction leading to the formation of the corresponding monoxide clusters Fe n O + In addition, several bond activations of dimethyl carbonate are observed which markedly differ from the behavior of the mononuclear cation. Nevertheless, a mechanistic analysis implies that the initial steps are the same for bare Fe + as well as small Fe n + clusters.