Tripodal M^III Complexes on Au(111) Surfaces: Towards Molecular “Lunar Modules”

Abstract

A series of tripodal MIII complexes (M = Ga, Mn, Fe) functionalized with three methylsulfanyl end‐groups for deposition on Au(111) were synthesized. The structures were designed to build rigid three‐dimensional molecular structures that stand on their own with multiple attachments on the metallic surface. The coordination compounds are based on a trensal [(tris(2,2′,2"‐salicylideneimino)triethylamine)] Schiff base ligand which provides stable metal complexes. The molecular structures of GaIII, FeIII, and MnIII complexes were determined by single‐crystal X‐ray diffraction crystallography. Magnetic properties depend on the coordinated metal ion and vary from a diamagnetic GaIII complex to paramagnetic high‐spin FeIII and MnIII complexes. A submonolayer of the GaIII complex deposited on Au(111) was studied in a preliminary ultra‐high‐vacuum scanning tunneling microscopy (UHV‐STM) investigation.

Stability of functionalized platform molecules on Au(111)

“…Chemical anchor groups consisting of a molecular subunit or just a single atom are used to determine these parameters for a class of molecules. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Recently, platform molecules have been used as anchors to a substrate and to achieve decoupling from neighbor molecules. 16,17 Extended aromatic platforms are particularly interesting because they adhere to a substrate via physisorption instead of chemisorption.…”

Importance of the Anchor Group Position (Para versus Meta) in Tetraphenylmethane Tripods: Synthesis and Self‐Assembly Features

“…Our initial attempts toward tripodal model compounds were based on coordination complexes comprising both neutral M III complexes and charged tris(bipyridine)‐Ru II derivatives, but our recent molecular designs comprise purely organic scaffolds such as 9,9′‐spirobifluorenes …”

Rigid multipodal platforms for metal surfaces

“…Our group recently synthetized and employed a series of tripodal M(III) complexes ( Fig. 27 ) functionalized with three methylsulfanyl end groups for deposition on Au(111) [ 130 ]. The coordination core structure is based on a trensal [(tris(2,2’,2’’-salicylideneimino)triethylamine)] Schiff base ligand, which provides stable metal complexes.…”