Linker Redox Mediated Control of Morphology and Properties in Semiconducting Iron‐Semiquinoid Coordination Polymers

The emergence of conductive 2D and less commonly 3D coordination polymers (CPs) and metal–organic frameworks (MOFs) promises novel applications in many fields. However, the synthetic parameters for these electronically complex materials are not thoroughly understood. Here we report a new 3D semiconducting CP Fe5(C6O6)3, which is a fusion of 2D Fe‐semiquinoid materials and 3D cubic Fex(C6O6)y materials, by using a different initial redox‐state of the C6O6 linker. The material displays high electrical conductivity (0.02 S cm−1), broad electronic transitions, promising thermoelectric behavior (S2σ=7.0×10−9 W m−1 K−2), and strong antiferromagnetic interactions at room temperature. This material illustrates how controlling the oxidation states of redox‐active components in conducting CPs/MOFs can be a “pre‐synthetic” strategy to carefully tune material topologies and properties in contrast to more commonly encountered post‐synthetic modifications. A novel 3D semiconducting coordination polymer Fe5(C6O6)3 is reported with high conductivity, broad electronic transitions and interesting thermoelectric/magnetic properties. The unique structure and properties of this material illustrate that controlling the oxidation states of redox‐active components in conducting metal‐organic materials can be a “pre‐synthetic” strategy to carefully tune material topologies, properties, and functionalities.