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Recent advances in the synthesis of graphene fragments that possess unpaired π-electrons and display high-spin ground states have unlocked possibilities to explore exotic physical phenomena related to magnetism. Here, the authors demonstrate the magnetic bistability of a diradical nanographene that allows direct spin manipulation at the single-molecule level.

Single atom catalysts, comprising minute amounts of transition metals dispersed on inert substrates, have emerged as prominent materials in heterogenous catalysis but their precise arrangement on surfaces is challenging. Here, the authors introduce the on-surface synthesis of a single atom platform wherein atoms are firmly anchored to specific coordination sites evenly distributed along carbon-based polymers.

Graphene nanoribbons with zigzag edges are key candidates for spintronic applications due to their tunable bandgaps and spin-polarized edge states. Now it has been shown that hybrid ribbons embedded with metalloporphyrins enable strong electronic and magnetic coupling between distant metal centres, positioning such hybrids as promising materials for quantum devices.

The zigzag edges of graphene host edge-localized electronic states with aligned electron spins, but these states strongly interact with metallic substrates. Here, the authors measure the electronic structure of graphene nanoribbons after transferring them to an insulating support.

Heteroatom substitution in larger acenes represents a fundamental step towards precise engineering of the remarkable electronic properties of the acene family. Here, the authors present an on-surface synthesis strategy and detailed characterization for three undecacene analogs substituted with four nitrogen atoms.

On-surface synthesis relies on carefully designed molecular precursors that are thermally activated to afford desired, covalently coupled architectures. Here, the authors study the intramolecular reactions of vinyl groups in a poly-para-phenylene-based model system and provide a comprehensive description of the reaction steps taking place on the Au(111) surface under ultrahigh vacuum conditions.

On-surface methods can be used to synthesize organic molecules, polymers and nanomaterials, however, the diversity of conceivable products is limited by the number of known on-surface reactions. Now, a phenylene ring-forming reaction on a gold surface by intermolecular oxidative coupling of isopropyl substituents on arenes is reported. The reaction is probed using bond-resolved imaging and computational modelling.

Open-shell nanographenes are used to fabricate length-controlled antiferromagnetic spin-1/2 Heisenberg chains. It is revealed that the spin excitation spectra evolve from gapped to gapless following a power-law dependence on chain length, along with the visualization of the standing waves of confined single spinons.

p–n junctions are formed in heterostructures made of pristine and nitrogen-doped graphene nanoribbons.

Synthesis of atomically precise zigzag edges in graphene nanoribbons is demonstrated using a bottom-up strategy based on surface-assisted arrangement and reaction of precursor monomers; these nanoribbons have edge-localized states with large energy splittings.

Graphene nanoribbons exhibit an electronic bandgap and optical response that can be tuned with the ribbon width. Here, using reflectance difference spectroscopy, Denk et al.investigate the exciton-dominated optical absorption of graphene nanoribbons and its dependence on the exact atomic structure.

Using scanning tunnelling microscopy and spectroscopy, fractional edge excitations are observed in nanographene spin chains, enabling the potential to study strongly correlated phases in purely organic materials.

Heteroatom doping of buckybowls is a viable route to tune their intrinsic physico-chemical properties, but their synthesis remains challenging. Here, the authors report on a combined in-solution and on-surface synthetic strategy towards the fabrication of a buckybowl containing two fused nitrogen-doped pentagonal rings.

Open-shell nanographenes are promising for quantum technologies, but their magnetic stability has remained limited by weak exchange coupling. Now, two large rhombus-shaped nanographenes with zigzag peripheries, one with 48 carbon atoms and the other with 70, have been synthesized on gold and copper surfaces. The 70-carbon compound exhibits a large magnetic exchange coupling exceeding 100 meV.

Large polycyclic aromatic hydrocarbons or nanographenes have huge potential for organic electronics applications, but it is challenging to synthesize them in a controlled way. Now, a surface chemical route has been used to produce tailored nanographenes with atomically precise control over the final structure.

Polyacetylene is an ideal system to probe to gain a better understanding of the nature of charge transport in conducting polymers. Now, individual atomically precise polyacetylene chains have been synthesized on a copper surface and characterized using a range of techniques, revealing a doping-induced semiconductor-to-metal transition.

The synthesis of large acenes via traditional solution-chemistry routes is hindered by their poor solubility and high reactivity under ambient conditions. Here, the authors demonstrate the on-surface formation of large acenes, via visible-light-induced photo-dissociation of α-bisdiketone molecular precursors on an Au(111) substrate.

Topological frustration in the π-electron network of the polycyclic aromatic hydrocarbon C₃₈H₁₈ yields unpaired electrons and a magnetically non-trivial ground state. Here, the authors synthesize this molecule, known as Clar’s goblet, on Au(111) and characterize the antiferromagnetic ground state with scanning tunnelling microscopy.

Graphene nanoribbons are used to design robust nanomaterials with controlled periodic coupling of topological boundary states to create quasi-one-dimensional trivial and non-trivial electronic quantum phases.

The presence of graphitic nitrogen atoms within graphene nanoribbons has been predicted to strongly affect their electronic properties, but its experimental formation within such structures remains challenging. Here, the authors report on the on-surface synthesis of pyridine-extended 7-armchair graphene nanoribbons on Au(111), whereby graphitic nitrogen is preferentially formed after complete planarization through the formation of C–N bonds.

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.