"Doping" of Polyyne with an Organometallic Fragment Leads to Highly Conductive Metallapolyyne Molecular Wire.

Exploration of highly conductive molecules is essential to achieve single-molecule electronic devices. The present paper describes the results on single-molecule conductance study of polyyne wires doped with the organometallic Ru(dppe) fragment, X-(C≡C) -Ru(dppe)-(C≡C) -X. The metallapolyyne wires end-capped with the gold fragments (X = AuL) are subjected to single-molecule conductance measurements with the STM break junction technique, which reveal the high conductance (10-10 G; n = 2-4) with the low attenuation factor (0.25 Å) and the low contact resistance (33 kΩ). A unique "'doping'" effect of Ru(dppe) fragment was found to lead to the high performance as suggested by the hybrid density functional theory-nonequilibrium green function calculation.