Enhancing Single-Molecule Conductance of Platinum(ii) Complexes Through Synergistic Aromaticity-Assisted Structural Asymmetry

Seeking the strategies of designing highly conductive molecular structures is one of the core researches in molecular electronics. As asymmetric structure has manifested feasible properties in comprehensive fields, we introduce the structures of asymmetric platinum(II) complexes into the charge transport study at single-molecule scale for the first time. The single-molecule conductance measurement results reveal that, in platinum(II)-aryloligoynyl structures, the conductance of asymmetrically coordinated complexes is obviously higher than that of the symmetric isomers with the same molecular length, while the conductance is almost identical in symmetric and asymmetric platinum(II)-oligoynyl complexes Theoretical study uncovers that, upon connecting to the oligoynyl structure, the aromatic group effectively extends the π-system of the whole conductive backbone and gathers the HOMO population mainly on the longer oligoynyl ligand, which reduces the energy barrier in electron transport and enhances the conductance through HOMO energy lifting. This result provides feasible strategy for achieving high conductive molecular devices.