Assembly and Manipulation of a Prototypical N-Heterocyclic Carbene with a Metalloporphyrin Pedestal on a Solid Surface
Peter Knecht, Bodong Zhang, Joachim Reichert, David A. Duncan, Martin Schwarz, Felix Haag, Paul T. P. Ryan, Tien‐Lin Lee, Peter S. Deimel, P. Feulner, Francesco Allegretti, Willi Auwärter, Guillaume Médard, Ari P. Seitsonen, Johannes V. Barth, Anthoula C. Papageorgiou
Abstract
The controlled arrangement of N-heterocyclic carbenes (NHCs) on solid surfaces is a current challenge of surface functionalization. We introduce a strategy of using Ru porphyrins in order to control both the orientation and lateral arrangement of NHCs on a planar surface. The coupling of the NHC to the Ru porphyrin is a facile process which takes place on the interface: we apply NHCs as functional, robust pillars on well-defined, preassembled Ru porphyrin monolayers on silver and characterize these interfaces with atomic precision via a battery of experimental techniques and theoretical considerations. The NHCs assemble at room temperature modularly and reversibly on the Ru porphyrin arrays. We demonstrate a selective and complete functionalization of the Ru centers. With its binding, the NHC modifies the interaction of the Ru porphyrin with the Ag surface, displacing the Ru atom by 1 Å away from the surface. This arrangement of NHCs allows us to address individual ligands by controlled manipulation with the tip of a scanning tunneling microscope, creating patterned structures on the nanometer scale.