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Organometallic Palladium(III) Polymer and Copolymer
Assemblies for Superconductivity

Periodic Report Summary - PALLAS (Organometallic Palladium(III) Polymer and Copolymer Assemblies for Superconductivity)

One-dimensional metal wires are predicted to display valuable properties, including room temperature superconductivity. Molecular wires are useful materials in devices such as photovoltaic cells, and materials with modifiable conductive properties are of particular value. Few examples of 1-D metal wires exist, and despite more than a century of research, molecular metal wires that are metallic conductors are unknown.

We have achieved the synthesis and conductive properties of palladium-based molecular wires with a backbone constituted solely of metal-metal bonds. The wires are infinite 1-D chains in the solid state, organised by unsupported Pd-Pd bonds. Their conductive properties can be altered through controlled variation of the Pd oxidation state: molecular wires based on Pd2.5+ are metallic conductors, and wires based on Pd3+ are semiconductors. The bandgap of the semiconducting Pd3+ wires can be adjusted by chemical modification and correlates to wire length in solution. Due to the unsupported Pd-Pd bonds, the wires maintain a 1-D polymeric structure in solution, with lengths of up to 700 nm. Solution stability of the reported Pd wires makes them amenable to thin film coating, which is requisite for device fabrication.