  We have investigated charge transport in ZnTPPdT-Pyr molecular junctions
using the lithographic MCBJ technique at room temperature and cryogenic
temperature (6K). We combined low-bias statistical measurements with
spectroscopy of the molecular levels using I(V) characteristics. This
combination allows us to characterize the transport in a molecular junction in
detail. This complex molecule can form different junction configurations, which
is observed in trace histograms and in current-voltage (I(V)) measurements.
Both methods show that multiple stable single-molecule junction configurations
can be obtained by modulating the inter-electrode distance. In addition we
demonstrate that different ZnTPPdT-Pyr junction configurations can lead to
completely different spectroscopic features with the same conductance values.
We show that statistical low-bias conductance measurements should be
interpreted with care, and that the combination with I(V) spectroscopy
represents an essential tool for a more detailed characterization of the charge
transport in a single molecule.
