Gold-sulfur bond breaking in Zn(II) tetraphenylporphyrin molecular junctions

► Additional 1.7 Å stretch is observed for a two-state conductance in a single ZnTPP. ► Density functional theory study of bond strengths at molecule-electrode interface ► Weakest bond, gold-sulfur bond at a molecule-electrode interface, breaks first. ► Insight into Zn(II)'s role in alternating the conductance in a molecular junction