The conductances of molecular model junctions comprising a triazatriangulenium platform with or without an ethynyl spacer Light Biege Color Boosting Treatment and an upright Zn-porphyrin are probed with a low-temperature scanning probe microscope.The platform alone is found to be highly conductive.The ethynyl-linked Zn-porphyrin moiety reduces the conductance by three orders of magnitude and leads to an unexpected, non-monotonous variation of the force that was measured simultaneously at the tip of BODY LOTION the microscope.
Density functional theory calculations show that this variation results from an induced tilting of the porphyrin.