Single-molecule junctions of multinuclear organometallic wires: long-range carrier transport brought about by metal-metal interaction

Here, we report multinuclear organometallic molecular wires having (2,5-diethynylthiophene)diyl-Ru(dppe)(2) repeating units. Despite the molecular dimensions of 2-4 nm the multinuclear wires show high conductance (up to 10(-2) to 10(-3)G(0)) at the single-molecule level with small attenuation factors (beta) as revealed by STM-break junction measurements. The high performance can be attributed to the efficient energy alignment between the Fermi level of the metal electrodes and the HOMO levels of the multinuclear molecular wires as revealed by DFT-NEGF calculations. Electrochemical and DFT studies reveal that the strong Ru-Ru interaction through the bridging ligands raises the HOMO levels to access the Fermi level, leading to high conductance and small beta values.

Automated summary

This study reports multinuclear organometallic molecular wires with high conductance attributed to efficient energy alignment between the Fermi level of the metal electrodes and the HOMO levels of the molecular wires. Strong Ru-Ru interaction through bridging ligands raises the HOMO levels to access the Fermi level, leading to high conductance and small attenuation factors.