Surface‐Confined Single Molecules: Assembly and Disassembly of Nanosize Coordination Cages on Gold (111)

Abstract

A cavitand functionalized with four alkylthioether groups at the lower rim, and four tolylpyridine groups on the upper rim is able to bind to a gold surface by its thioether groups, and forms a coordination cage with [Pd(dppp)(CF(3)SO(3))(2)] by its pyridine groups. The cavitand or the cage complex can be inserted from solution into a self-assembled monolayer (SAM) of 11-mercaptoundecanol on gold. The inserted molecules can be individually detected as they protrude from the SAM by atomic force microscopy (AFM). The cages can be reversibly assembled and disassembled on the gold surface. AFM can distinguish between single cavitand and cage molecules of 2.5 nm and 5.8 nm height, respectively.

Introduction of Water-Solubilizing Groups at the Lower Rim of Tolylpyridine-Bridged Cavitands

“…This requires incorporating the water-solubilizing groups at the lower rim of the cavitand tetradentate ligand, leaving the upper apical and bridge positions free for ligand introduction. In our case the ligands responsible for metal coordination are tolylpyridine bridging units appended to the upper rim [3,7] as separate entities from the hydrophilic groups. By adding two equivalents of a suitable metal precursor to a water solution of these cavitands it would be possible to assemble a water-soluble nanosized cage directly in aqueous solution ( Figure 1).…”

Supramolecular architectures of porphyrins on surfaces: The structural evolution from 1D to 2D to 3D to devices

“…doi:10.1016/j.ccr.2010.05.006 organic molecules. In order to construct such hybrid molecularbased nanoscale devices, methods for the controlled fabrication of well-defined organic nanostructures need to be developed [2][3][4]. One of the most promising methods to date is the "bottom-up" approach, wherein ordered structures with nanometer precision over an extended large scale can be constructed.…”

Hierarchical Self‐Assembly of Luminescent EuIII Complexes on Silicon

“…Among them, cavitands [5] are particularly versatile systems, the complexation ability of which has been exploited not only for the recognition of target molecules [6] but also for the fabrication of well-defined 2D and 3D molecular assemblies. [7] Some examples of cavitand-decorated surfaces of gold [8] and silicon [9] in which the molecular-recognition properties of cavitands have been exploited for the precise fabrication of a specific molecular structure have been reported. Recently, β-cyclodextrins were employed as molecular receptors for the self-assembly of Eu III luminescent complexes on glass.…”