Single-Molecule Junction of a Cationic Rh(III) Polyyne Molecular Wire

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Single-molecule conductance studies are crucial for molecular electronics.
• Metal-containing molecular wires are less explored than organic ones.
• Current metal-containing wires lack sensitivity to metal centers, hindering design.

Purpose of the Study:

• To synthesize and measure the single-molecule conductance of novel bis(butadiynyl)rhodium wires.
• To investigate the potential of these metallapolyynes as high-performance molecular wires.
• To understand the influence of metal centers on conductance properties.

Main Methods:

• Synthesis of bis(butadiynyl)rhodium wires with tetracarbene ligands.
• Scanning tunneling microscopy (STM) break-junction measurements for single-molecule conductance.
• Hybrid density functional theory (DFT) and non-equilibrium Green's function (NEGF) calculations.

Main Results:

• Rhodium wires demonstrated high single-molecule conductance ((6-7) × 10^-3 G0).
• Conductance values exceeded those of similar length organic polyyne wires.
• Transmission spectra revealed high sensitivity to metal fragment species.

Conclusions:

• Bis(butadiynyl)rhodium wires are rare examples of Rh(III) diacetylide molecular wires.
• Metallapolyynes exhibit superior conductance compared to organic analogues.
• These metallapolyynes are suitable platforms for rational design of molecular wires.