On-surface synthesis

The effective control of chirality on surfaces is crucial for applications such as enantioselective heterogeneous catalysis and nonlinear optics. Here, the authors study the on-surface synthesis of organometallic polymers and their chiral expression on Ag(110), demonstrating that kinetic effects play an important role in determining polymer chirality.

The atomically precise on-surface synthesis of carbon-based nanostructures is of relevance for electronic and optoelectronic devices, but achieving control over such architectures remains challenging. Here, the authors demonstrate the selective stepwise on-surface synthesis of nitrogen-doped porous carbon nanoribbons with well-defined topologies and structures, and predict variable band gaps dependent on ribbon width.

High resolution force measurements of molecules on surfaces using non-contact atomic force microscopy are typically performed at cryogenic temperatures. Here, the authors outline a reliable protocol for acquiring three-dimensional force map data at room temperature, demonstrating such capabilities on isolated cobalt phthalocyanine molecules and islands of C60 molecules.

The water surface has recently proven to be an effective platform for the synthesis of large-area two-dimensional polymers with high crystallinity. Here, the authors report the on-water synthesis of a crystalline monolayer 2D polyimide, as well as its incorporation into organic–inorganic hybrid van der Waals heterostructures that display significant charge transfer and high electron mobility.

Single atom catalysts dispersed on a surface demonstrate great promise for a variety of catalytic reactions, but their aggregation leads to a degradation of catalytic activity. Here, the authors use quantum mechanical calculations to study the catalytic activity of Cu adatoms stabilized with N-heterocyclic carbenes (NHCs) on a Cu(100) surface, finding that NHC-decoration significantly reduces the energy barriers to electrocatalytic CO hydrogenation and C–C coupling.

The on-surface synthesis of graphene nanoribbons with control over their length and final surface coverage is desirable for electronic applications. Here, the authors outline a protocol to produce long and isolated graphene nanoribbons on an Au(111) surface, achieving lengths of up coverage down to ~0.4 monolayer, of potential value for mono-molecular electronics. to 50 nm and a low surface coverage down to ~0.4 monolayer, of potential value for mono-molecular electronics.

Supramolecular networks deposited on surfaces are of interest for a range of applications, but expanding monolayers to well-ordered multilayers remains a significant challenge, not least because analytical tools capable of probing such assemblies are limited. Here, the authors demonstrate that combining AFM-IR with STM enables an assessment of the differences in molecular conformations between 2D and 3D supramolecular networks adsorbed onto a HOPG surface.

On-surface synthesis is a key tool to access low dimensional carbon-based nanomaterials with atomic precision. Here, the authors synthesize a nitrogen-doped nanographene structure with an [18]annulene pore on Ag(111) through sequential debromination, aryl–aryl coupling, cyclodehydrogenation and C–N coupling reactions from a 3,12-dibromo-7,8-diaza[5]helicene precursor.

The experimental realization of p-orbital systems with exotic quantum phases is desirable for the obtainment of strongly correlated materials. Here, two sublattices composed of molecules with p-orbital characteristics are combined to realize a p-orbital honeycomb-Kagome lattice in a two dimensional metal–organic framework on a Au(111) substrate.

On-surface synthesis is a useful tool to produce extended macrocyclic structures with atomic precision, with only one type of macrocycle typically formed through on-surface coupling reactions. Here, distinct domains of four-, six- and eight-membered tetraphenylethylene-based macrocycles are synthesized on Ag(111) as segregated large-area mono-component crystals.

[n]cycloparaphenylenes feature extensive para-conjugation that leads to useful electronic and optoelectronic properties, but their strained topology prevents their conversion into planar macrocycles. Now, on-surface coupling of cleverly designed precursors affords planar π-extended [12]cycloparaphenylene.

Rutile TiO₂ is a prominent photocatalyst for overall water splitting, but the on-surface activation of hydrogen atoms is still not fully understood. Here, the authors use atomic force and kelvin probe force microscopy to study the lateral manipulation of hydrogen on a rutile (110) surface.

Mechanistic insight into enantioselective reactions at intrinsically chiral surfaces can be challenging to obtain. Here the catalytic activity of Pd₁- and Pd₃-terminated PdGa{111} surfaces is shown to differ substantially, with Pd₁-terminated surfaces promoting on-surface azide– alkyne cycloadditions enantioand regioselectively.

Ullmann-type reactions on metal surfaces are widely studied examples of on-surface synthesis. Here the combination of normal incidence X-ray standing wave analysis, X-ray photoelectron spectroscopy, and scanning tunneling microscopy enables the characterisation of molecular conformations in two such reactions.