Redox-active ruthenium-organic polyhedra with tunable surface functionality and porosities

Dinuclear ruthenium paddlewheel complexes exhibit high structural stability against redox reactions. The use of these chemical motifs for the construction of Ru-based metal-organic polyhedral (RuMOPs) provides a route for redox-active porous materials. However, there are few studies on the synthesis and characterization of RuMOPs due to the difficulty of controlling the assembling process via the ligand-exchange reaction of equatorial acetates of the diruthenium tetraacetate precursors with dicarboxylic acid ligands. In this study, we synthesized three novel cuboctahedral RuMOPs based on the Ru2(II/III)-paddlewheel units with different alkyl functionalizations on the benzene-1,3-dicarboxylate moieties. We evaluated the effect of the external functionalization on the molecular packing and the porous and redox properties. The electrochemical measurements revealed the multi-electron transferred redox process where the electron donating/withdrawing nature of the functional groups allows the control of the redox behavior.