Assembly of Dendrimers with Redox‐Active [{CpFe(μ 3 ‐CO)} 4 ] Clusters at the Periphery and Their Application to Oxo‐Anion and Adenosine‐5′‐Triphosphate Sensing

9, 16, or 27 [CpFe(μ 3 ‐CO)] 4 clusters contain the title assemblies (see picture). The one‐electron oxidation Fe 4 →Fe 4 + of all Fe 4 units appears as a single reversible cyclic voltammetry wave and was used in solution and with dendrimer‐modified electrodes for oxo‐anion recognition. ATP 2− is selectively recognized and better than H 2 PO 4 − . The larger the dendrimer, the easier is the re‐use of the modified electrode sensor.