Analysis of Single Molecule Conductance of Heterogeneous Porphyrin Arrays by Partial Transmission Probabilities

Single molecule conductance (SMC) of a series of porphyrin derivatives, whose porphyrin units are connected through a phenylene bridge that have one or two thiolate end groups, was measured by a scanning tunneling microscopic break junction (STM‐BJ) technique. The observed conductance values were analyzed by partial transmission probabilities ( T i ) for the molecular parts using the equation G = G 0∏ i N T i . Unique combination of T i was obtained, which indicates the validity of this analysis. By the analysis, the free‐base porphyrin ring interacting with the gold electrode was found to show a greater transmission probability T por‐Au than that of the bridge between thiolate and the gold electrode ( T S‐Au ).