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Regiospecific C−H activation is a promising approach to achieve extended polymers with tailored structures. While a recent on‐surface synthetic approach has enabled regioselective homocoupling of heteroaromatic molecules, only small oligomers have been achieved. Herein, selective C−H activation for dehydrogenative C−C couplings of hexaazatriphenylene by Scholl reaction is reported for the first time. By combining low‐temperature scanning tunneling microscopy (STM) and atomic force microscopy (AFM), we revealed the formation of one‐dimensional polymers with a double‐chain structure. The details of the growth process are rationalized by density functional theory (DFT) calculations, pointing out a cooperative catalytic action of Na and Ag adatoms in steering the C−H selectivity for the polymerization. [ABSTRACT FROM AUTHOR]

Nitrogen‐doped Kagome graphene (N‐KG) has been theoretically predicted as a candidate for the emergence of a topological band gap as well as unconventional superconductivity. However, its physical realization still remains very elusive. Here, we report on a substrate‐assisted reaction on Ag(111) for the synthesis of two‐dimensional graphene sheets possessing a long‐range honeycomb Kagome lattice. Low‐temperature scanning tunneling microscopy (STM) and atomic force microscopy (AFM) with a CO‐terminated tip supported by density functional theory (DFT) are employed to scrutinize the structural and electronic properties of the N‐KG down to the atomic scale. We demonstrate its semiconducting character due to the nitrogen doping as well as the emergence of Kagome flat bands near the Fermi level which would open new routes towards the design of graphene‐based topological materials. [ABSTRACT FROM AUTHOR]

Structures of the aromatic N-heterocyclic hexaazatriphenylene (HAT) molecular synthon obtained by surface-assisted self-assembly were analyzed with sub-Å resolution by means of noncontact atomic force microscopy (nc-AFM), both in the kinetically trapped amorphous state and in the thermodynamically stable crystalline phase. These results reveal how the crystallization governs the length scale of the network order for non-flexible molecular species without affecting the local bonding schemes. The capability of nc-AFM to accurately resolve structural relaxations will be highly relevant for the characterization of vitreous two-dimensional supramolecular materials. [ABSTRACT FROM AUTHOR]

Frontispiece: On-Surface Synthesis of Nitrogen-Doped Kagome Graphene Atomic force microscopy, density functional calculations, Kagome graphene, on-surface synthesis, scanning probe microscopy Keywords: atomic force microscopy; density functional calculations; Kagome graphene; on-surface synthesis; scanning probe microscopy EN atomic force microscopy density functional calculations Kagome graphene on-surface synthesis scanning probe microscopy 1 1 1 04/01/21 20210406 NES 210406 B Metal-Organic Frameworks b In their Research Article on page 8370, Natalia B. Shustova et al. report on heterometallic actinide-containing photoresponsive metal-organic frameworks and the tuning of their electronic properties. [Extracted from the article]