Self-Metalation of Phthalocyanine Molecules with Silver Surface Atoms by Adsorption on Ag(110)

Abstract

We report that metal-free phthalocyanine (H 2 Pc) molecules with a central cavity are able to incorporate Ag atoms from an Ag(110) surface thus creating silver-phthalocyanine (AgPc). The reaction was investigated by means of scanning tunneling microscopy (STM) under ultrahigh vacuum, and the metalation of H 2 Pc at the interface was confirmed with X-ray photoelectron spectroscopy. Three different kinds of molecules were found on the surface that are assigned to H 2 Pc, the corresponding dehydrogenated molecules (Pc) and AgPc. The relative amounts of Pc and AgPc increase with increasing annealing temperature. We suggest that the reaction with Ag atoms from the steps of the surface occurs favorably only for already dehydrogenated molecules; thus, the metalation of H 2 Pc is likely limited by the heat-induced dehydrogenation. Density functional theory simulations of the reaction path are presented to corroborate this hypothesis.

Identification of On-Surface Reaction Mechanism by Targeted Metalation

“…4,25 Metalation with silver has been observed for tetrapyrrols on Ag surfaces. [26][27][28][29] The N1s binding energy of the nitrogens in the macrocycle (398.4 eV) is consistent with N-Ag in Ag-phthalocyanine obtained by metalation on Ag(110) 26 and significantly lower than for N-Cu in Cu-pyrphyrin/Cu(111). 23 Due to the small size of the pyrphyrin macrocycle, it is unlikely that a Ag adatom penetrates the macrocycle and is coordinated exactly in the molecular plane.…”

In vacuo interfacial tetrapyrrole metallation

“…134 The very high reaction barrier for the metallation with silver can be lowered by choosing a lower index surface facet and preliminary dehydrogenation of the macrocycle, as recently shown by Smykalla et al for the self-metallation of 2H-Pc on Ag(110). 87 For the even less reactive gold surfaces, no observations whatsoever pointing to self-metallation have been reported so far (not even when direct interaction with Au adatoms was shown 142 ), even though they are widely used as a substrate for porphyrin and phthalocyanine experiments. 85,90,99,116,[143][144][145] For different surface facets the employed molecules differ, such that a direct comparison is not possible.…”

Probing the Reactivity of Functionalized Surfaces by Porphyrin Metalation

“…The functionalization involves atomically thin c(2x2) superstructures of N and Cl, which are formed on Cu(001) (termed as N/Cu and Cl/Cu respectively, Figure 1b,c). The metalation reaction proved to be well suited for this purpose as it has been investigated on a wide range of surfaces [14][15][16][17][18][19][20][21][22][23][24][25] and it involves the movement of metal atoms in outof-plane direction from the substrate to the initially metal free porphyrin. The evolution of the metalation can be conveniently assessed by XPS which is sensitive to the chemical environment Communications DOI: 10.1002/slct.201600215 of the porphyrin-nitrogen atoms within the precursor, 2HTPP, as well as in the reaction product, i.e.…”