Competing Interactions in Surface Reticulation with a Prochiral Dicarbonitrile Linker

The organic and metal-directed assembly of a prochiral carbonitrile (CN) oligophenyl molecule on a smooth noble metal substrate was investigated by combined scanning tunneling microscopy and computational modeling. The molecule is functionalized with two CN groups in meta and para positions of the terminating phenyl rings of the p-terphenyl backbone. Upon deposition on a Ag(111) surface, we observe two different organic supramolecular networks, one of them reflecting a chiroselective assembly. After coevaporating small amounts of Co, a hybrid network comprising both CN-phenyl and metal coordination bond motifs could be observed. Intriguingly, the CN group in the para position is favored for the metal coordination, whereas the meta group remains in a CN-phenyl motif. Computational modeling suggest that the high stability of the meta CN-phenyl motif is causing this selective interaction. An increase of the metal adatom ratio eventually induces divergent assembly of a room-temperature stable 2D random metal-organic network.