Competitive metal‐coordination of hexaaminotriphenylene on Cu(111) by intrinsic copper versus extrinsic nickel adatoms

The interplay between self‐assembly and surface chemistry of 2,3,6,7,10,11‐hexaminotriphenylene (HATP) on Cu(111) was complementarily studied by high‐resolution Scanning‐Tunneling‐Microscopy (STM) and X‐ray Photoelectron Spectroscopy (XPS) under ultra‐high vacuum conditions. To shed light on competitive metal‐coordination, comparative experiments were carried out on pristine and nickel‐covered Cu(111). Directly after room temperature deposition of HATP onto pristine Cu(111) self‐assembled aggregates were observed by STM, while XPS indicated non‐deprotonated amino groups. Annealing up to 200 °C activated the progressive single deprotonation of all amino groups as indicated by chemical shifts of both N 1s and C 1s core levels in the XP spectra. This enabled the formation of topologically versatile π‐d conjugated coordination networks with intrinsic copper adatoms. The basic motif of these networks was a metal‐organic trimer, where three HATP molecules were coordinated by Cu3 clusters, as corroborated by accompanying Density Functional Theory (DFT) simulations. Additional deposition of more reactive nickel atoms resulted in both chemical and structural changes with deprotonation and formation of bis(diimino)‐Ni bonded networks already at room temperature. Even though fused hexagonal pores were observed, extended honeycomb networks remained elusive, as tentatively explained by a restricted reversibility of these metal‐organic bonds.