Ligation of Carbon\nMonoxide at Cobalt Single-Metal-Atom\nSites in a Surface-Confined Metal–Organic Network: Oxidation\nState, Anharmonicity, and Long-Range Lateral Interactions

Ligation of carbon monoxide at the single-metal-atom\ncobalt sites\nof a surface-confined tetra-pyridyl porphyrin coordination network\nis investigated under near-ambient pressure conditions at room temperature.\nIt is found that (anti)cooperative effects associated with network-mediated\nlateral interactions allow tuning of the adduct adsorption energy\nand of its coverage dependence. The mechanism involves charge and\ngeometric distortions, induced upon ligation, that are transferred\nto proximal sites of the network as far as a few nanometers away through\ndeformation of the pyridinic residues. Anharmonic contributions to\nthe ligation potential are evidenced via the light-induced population\nof the vibrational hot band of the internal C–O stretching\nmode, known to play a role in the C–O dissociation energy barrier\nand, thus, in the CO activation toward reaction.