Assembly and Manipulation of a Prototypical N-Heterocyclic Carbene with a Metalloporphyrin Pedestal on a Solid Surface

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 welldefined, 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.

Conformational Control of Chemical Reactivity for Surface‐Confined Ru‐Porphyrins

“…These conformational adaptations can be interpreted as a rather strong surface trans ‐effect. [ 10 , 12a , 32 ]…”

Wachstum von N‐heterocyclischen Carbenen auf Cu(100) und Cu(111): von einzelnen Molekülen bis hin zu Inseln mit magischen Zahlen

“…NHCs wurden für die Funktionalisierung unterschiedlicher metallbasierter Nanopartikeln eingesetzt [6] . Im Gegensatz dazu wurde die Adsorption von NHCs bezüglich der ebenen Oberflächen bisher meist auf Goldoberflächen untersucht, [5a, 7] während nur wenige Arbeiten auf anderen Metallen wie Kupfer, [7k, 8] Silber [8b, 9] oder Platin [10] durchgeführt wurden. Die Adsorption auf ebenen Siliziumoberflächen wurde ebenfalls berichtet [11] .…”

The Flexible On-Surface Self-Assembly of a Low-Symmetry Mabiq Ligand: An Unconventional Metal-Assisted Phase Transformation on Ag(111)

“…These N 4 -macrocyclic compounds are versatile building blocks whose properties can be modified by the centrally coordinated metal ions and further tuned by tailoring the molecular periphery with different functional groups. Surface attachment offers practical application of metal complexes within artificial photosystems, can overcome disadvantages of homogeneous systemse.g., catalyst aggregation or solubility and stability issuesand often leads to altered or enhanced reactivities of the catalysts. − Tetrapyrrole macrocycles are well-suited for heterogeneous functionalization, given their ability to self-assemble into highly ordered structures on solid surfaces. − Consequently, novel, hierarchical assemblies and nanostructures can be generated, − with controlled properties and tailored functionality. , The coordination of metal and nonmetal ions to the ligands can be achieved via post-synthetic modification on surfaces; the metals can be incorporated either inside the macrocycle or in layered multi-decker structures . Importantly, the self-assembly of tetrapyrrole complexes on semiconductor or insulating surfaces ,− can serve as a patterning tool to generate regular arrays of well-defined single-atom catalytic sites. , Finally, surface-bound macrocycles have been shown to stabilize rare oxidation states such as Ni­(I), , Ti­(II), Ti­(III), and Si­(III), which may in turn enable a broader range of reactivities and novel applications.…”