Direct Synthesis of Semimetal Phthalocyanines on a Surface with Insights into Interfacial Properties

On-surface engineering of supramolecular structures has attracted considerable interest during the past few decades. However, organic nanostructures coordinated by group V semimetals have rarely been demonstrated. Herein, we report the metalation of a metal-free phthalocyanine (H2Pc) via the incorporation of semimetal atoms (Sb and Bi) with insights from X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and density functional theory. While H2Pc becomes completely metalized on the Sb(111) surface after annealing to 200 °C, the metalation of H2Pc is only partially triggered on Bi(111) at annealing to 300 °C, and the complete metalation is done after further higher temperature annealing. Inspired by the metalation path predicted by DFT calculations, we propose that the metalation of H2Pc on Sb and Bi semimetals is possible by the dissociation of hydrogen atoms from the pyrrolic nitrogen atom as a result of the orbital hybridization between the N-sp2 state and the Bi-6py state, and the metalation process needs to overcome a relatively high energy barrier due to the weak mixing of atomic orbitals at discriminated energy levels. While Bi/Sb coordinated organic nanostructures have been seldom investigated before, the direct synthesis of SbPc/BiPc via on-surface reaction in this report might bring promising progress for physical chemistry and related fields.