Central metal dependence of conformation and self-assembly of porphyrins on Ag(110)

摘要

The conformation and self-assembly of tertiary-butylphenyl substituted free-base and metal porphyrins (M-TBPP) on Ag(110) have been investigated as a function of the central metals (M = 2H, Cu, Pt, Ni, Zn, and Co) using scanning tunneling microscopy and low-energy electron diffraction. In the case of M = Cu, Pt, Ni, and Zn, a metastable adsorption structure is formed by the deposition below about 270 K and irreversibly transformed into a stable one after thermal annealing above 280 K. Nevertheless, we find that 2H- and Co-TBPP molecules do not exhibit structural transformation even after thermal annealing. The distinct adsorption behaviors should be related mainly to the porphyrin-substrate interactions depending on the central metal in M-TBPP.