Molten Metal Synthesis of Nanographenes

This manuscript describes a simple and effective method to cyclodehydrogenate arenes using liquid alkali metals. Direct reaction between molten potassium and arenes forms 6-membered rings and zigzag edged structures within polyarenes. The approach is extended to integration of pyridinic nitrogen and 5-membered rings to arene structures and synthesis of larger, open-shell nanographenes.

Alignment Control of Ferrite-Decorated Nanocarbon Material for 3D Printing

This paper demonstrates the potential of anisotropic 3D printing for alignable carbon nanomaterials. The ferrite-decorated nanocarbon material was synthesized via a sodium solvation process using epichlorohydrin as the coupling agent. Employing a one-pot synthesis approach, the novel material was incorporated into a 3D photopolymer, manipulated, and printed using a low-cost microscale 3D printer, equipped with digital micromirror lithography, monitoring optics, and magnetic actuators. This technique highlights the ability to control the microstructure of 3D-printed objects with sub-micron precision for applications such as microelectrode sensors and microrobot fabrication.

Tackling Solubility Issues in Organic Synthesis: Solid-State Cross-Coupling of Insoluble Aryl Halides

Conventional organic synthesis generally relies on the use of liquid organic solvents to dissolve the reactants. Therefore, reactions of sparingly soluble or insoluble substrates are challenging and often ineffective. The development of a solvent-independent solid-state approach that overcomes this longstanding solubility issue would provide innovative synthetic solutions and access to new areas of chemical space. Here, we report extremely fast and highly efficient solid-state palladium-catalyzed Suzuki-Miyaura cross-coupling reactions via a high-temperature ball-milling technique. This solid-state protocol enables the highly efficient cross-couplings of insoluble aryl halides with large polyaromatic structures that are barely reactive under conventional solution-based conditions. Notably, we discovered a new luminescent organic material with a strong red emission. This material was prepared via the solid-state coupling of Pigment violet 23, a compound that has so far not been involved in molecular transformations due to its extremely low solubility. This study thus provides a practical method for accessing unexplored areas of chemical space through molecular transformations of insoluble organic compounds that cannot be carried out by any other approach.

Templated Synthesis of End-Functionalized Graphene Nanoribbons through Living Ring-Opening Alkyne Metathesis Polymerization

Atomically precise bottom-up synthesized graphene nanoribbons (GNRs) are promising candidates for next-generation electronic materials. The incorporation of these highly tunable semiconductors into complex device architectures requires the development of synthetic tools that provide control over the absolute length, the sequence, and the end groups of GNRs. Here, we report the living chain-growth synthesis of chevron-type GNRs (cGNRs) templated by a poly-(arylene ethynylene) precursor prepared through ring-opening alkyne metathesis polymerization (ROAMP). The strained triple bonds of a macrocyclic monomer serve both as the site of polymerization and the reaction center for an annulation reaction that laterally extends the conjugated backbone to give cGNRs with predetermined lengths and end groups. The structural control provided by a living polymer-templated synthesis of GNRs paves the way for their future integration into hierarchical assemblies, sequence-defined heterojunctions, and well-defined single-GNR transistors via block copolymer templates.