1：Experimental Design and Method Selection:

The study utilized low temperature scanning tunneling microscopy (STM) to analyze the tautomerization behavior of tetra-tert-butyl phthalocyanine (ttbPc) isomers on a Ag(111) surface. The methodology included comparing ttbPc with phthalocyanine (H2Pc) to demonstrate the decoupling effect of tert-butyl substituents from the surface.

2：Sample Selection and Data Sources:

ttbPc and H2Pc molecules were deposited on a clean Ag(111) surface at room-temperature using a home-built evaporator. The Ag(111) surface was prepared by cycles of Ar+ ion sputtering and subsequent annealing.

3：List of Experimental Equipment and Materials:

A home-built low temperature STM at 4.5 K, Ag(111) surface, ttbPc and H2Pc molecules, W tip created by electrochemically etching a W wire with a 2 mol NaOH solution.

4：5 K, Ag(111) surface, ttbPc and H2Pc molecules, W tip created by electrochemically etching a W wire with a 2 mol NaOH solution. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Measurements were performed with a W tip, applying a bias voltage and tunneling current to induce tautomerization. The switching rate was measured by recording telegraph noise curves of the z-signal.

5：Data Analysis Methods:

The switching rate was analyzed by dividing the number of observed switching events by the total measuring time. The data were analyzed with a fit function to determine energetic thresholds.