Metal–organic polyhedra constructed from dinuclear ruthenium paddlewheels

• Four MOPs were constructed based on dinuclear Ru paddlewheels.
• Ligand-Angle-Driven Assembly was applied to obtain MOPs with different structure.
• Ru2n+ paddlewheels show redox activity even after coordinated into MOPs.
• The structure of MOPs were barely affected by the oxidation states of Ru2n+ centers.
• Both electrochemistry and magnetic properties show moderate communications between the Ru25+ paddlewheels.

Reactions of Ru2n+ [n = 4 for Ru2(OAc)4 and n = 5 for Ru2(OAc)4Cl] with H2CDC (9H-3,6-carbazoledicarboxylic acid), H2BBDC (5-tert-butyl-1,3-benzenedicarboxylic acid) and H2BDC (1,3-benzenedicarboxylic acid) were conducted in inert atmospheres under solvothermal conditions in a sealed tube. Two octahedral cages, [Ru2(CDC)2Cl]6, 1 and [Ru2(CDC)2]6, 2 were obtained when starting from Ru2n+ with CDC, and two cuboctahedral cages, [Ru2(BBDC)2Cl]12, 3 and [Ru2(BDC)2]12, 4 were yielded when starting from Ru2n+ with BDC based linkers. Structures of these MOPs were characterized by single crystal X-ray analyses. The resulted MOPs have shown redox activity and magnetic properties similar to their parent metal complexes.

Four metal-organic polyhedra based on Ru2n+ cores and ditopic ligands have been prepared via Ligand-Angle-Driven Assembly and were structurally characterized. Octahedral and cuboctahedral cages were yielded by starting from linkers with different angles. Cyclic voltammetry measurements have revealed that reversible oxidation and reduction between Ru24+ and Ru25+ oxidation states are possible under mild conditions. Weak electron communication has been found between Ru2 nodes in compound 4. The different oxidation states show only minor changes in structure, suggesting that these polyhedra could be incorporated into a larger framework that would allow redox reactions to take place at a Ru atom site without distorting the overall structure. Figure optionsDownload as PowerPoint slide