Tailoring Pt-Based Organometallic Porous Network on Ag(111): A Model System for "Host-Guest" Chemistry

Metal-organic frameworks (MOFs) have proven to be versatile platforms for anchoring individual metal atoms, which can act as single-atom catalysts. Due to their well-defined geometric and electronic structure, high porosity, and adjustable pore size, MOFs can modulate the catalytic performance of anchored individual atoms. In this work, we explored the surface-assisted synthesis of 2D surface metal-organic networks (SMONs) of 1,3,5-tris-[4-(pyridine)-[1,1'-biphenyl]-benzene] (TPyPPB) coordinated with Pt atoms on Ag(111) by using scanning tunneling microscopy at room temperature. The Pt deposition was performed in two routes: (i) by using the dichloro-(1,10-phenanthroline)-platinum-(II) (Cl₂PhPt) or (ii) by direct deposition of Pt atoms. Using Cl₂PhPt as a Pt source and applying various annealing sequences at a temperature of 400 K, a long-range hexagonal SMONs is obtained. After the dechlorination of the Cl₂PhPt molecule, individual Pt atoms establish quadruple coordination with two N atoms at the pyridyl end groups of the TPyPPB molecule and two Cl atoms. These pores have efficiently induced the formation of large molecules that behave like rotors. Such a system has the potential to open new frontiers and shed light on a better understanding of the physical-chemistry mechanisms involved in "host-guest" chemistry.