Intermolecular On-Surface σ-Bond Metathesis

Abstract

Silylation and desilylation are important functional group manipulations in solution-phase organic chemistry that are heavily used to protect/deprotect different functionalities. Herein, we disclose the first examples of the σ-bond metathesis of silylated alkynes with aromatic carboxylic acids on the Ag(111) and Au(111) surfaces to give the corresponding terminal alkynes and silyl esters, which is supported by density functional theory calculations and further confirmed by X-ray photoelectron spectroscopy analysis. Such a protecting group strategy applied to on-surface chemistry allows self-assembly structures to be generated from molecules that are inherently unstable in solution and in the solid state. This is shown by the successful formation of self-assembled hexaethynylbenzene at Ag(111). Furthermore, it is also shown that on the Au(111) surface this σ-bond metathesis can be combined with Glaser coupling to fabricate covalent polymers via a cascade process.

Ultrathin graphdiyne film on graphene through solution-phase van der Waals epitaxy

“…Encouraged by these intriguing properties of GDY, tremendous efforts have been made to experimentally synthesize such 2D acetylenic carbon allotropes. For example, dry chemistry approaches have been used, but only noncovalent assemblies or oligomers are derived on the metal surface under ultrahigh vacuum ( 17 , 18 ). In contrast, the wet chemistry approach achieved the scalable synthesis of GDY and further improved the quality of GDY.…”

Reaction Selectivity in On‐Surface Chemistry by Surface Coverage Control—Alkyne Dimerization versus Alkyne Trimerization

“…Also protective group strategies that are well established in solutionphasec hemistry have been developed. [30][31][32] In addition, additives have been used to supress acertain reaction [33,34] and preorganization by different self-assembled structures has been shownt oi nfluencet he reactivity. [35,36] Alternatively, one can run the process at different coverages [37][38][39] or temperatures [40] and use these readily varied reactionp arameters for product control.H owever, to date only few exampleso nr eactionc ontrol based on surfacec overage in two-dimensionalc hemistry have been reported.…”

Direct Formation of C−C Triple‐Bonded Structural Motifs by On‐Surface Dehalogenative Homocouplings of Tribromomethyl‐Substituted Arenes

“…[1][2][3][4] As ar esult, many unexpected reactions have been achieved on different surfaces. [5][6][7][8][9] Thus on-surface synthesis demonstrates remarkable potential in the fabrication of novel nanostructures/nanomaterials that still remain challenging to be obtained by traditional synthetic methods.F or instance, carbon materials,i ncluding fullerenes,g raphene,g raphene nanoribbons,s ingle-chirality carbon nanotubes,a nd metalated carbyne,a sw ell as different hydrocarbons have been successfully fabricated by such on-surface synthetic strategies. [10][11][12][13][14] Remarkably,the formation of acetylenic scaffolds (i.e., sphybridized carbon structures) has been attempted on surfaces, and has been advanced recently.…”