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Precise organization of matter across multiple length scales is of particular interest because of its great potential with advanced functions and properties. Here we demonstrate a simple yet versatile strategy that enables the organization of hydrophobic nanoparticles within the covalent organic framework (COF) in an emulsion droplet. The interfacial polymerization takes place upon the addition of Lewis acid in the aqueous phase, which allows the formation of COF after a crystallization process. Meanwhile, the interaction between nanoparticles and COF is realized by the use of amine-aldehyde reactions in the nearest loci of the nanoparticles. Importantly, the competition between the nanoparticle self-assembly and interfacial polymerization allows control over the spatial distribution of nanoparticles within COF. As a general strategy, a wide variety of COF-wrapped nanoparticle assemblies can be synthesized and these hybridized nanomaterials could find applications in optoelectronics, heterogeneous catalysis and energy chemistry.

The design of metal-bearing carbon-based materials with unique structures and intriguing properties is highly desirable in the fields of physics, chemistry, and materials science.Here, within swarm-intelligence structure search and first-principles computations, we uncovered several hitherto unknown sodium carbides (i.e., Na 4 C, Na 3 C 2 , NaC, Na 2 C 3 , and NaC 2 ) under high pressure. Intriguingly, the C atom arrangement reveals multiple structure evolution behavior with increased carbon content, from isolated anions in Na 4 C, tetramers in Na 3 C 2 , extended chains in NaC, pentagonal rings in Na 2 C 3 , to eventually hexagonal rings in NaC 2 . Among predicted phases, the superconducting critical temperature T c of NaC 2 could approach ∼42 K at 80 GPa, which is slightly higher than the T c of 39 K in the highest phonon-mediated superconductivity of MgB 2 at ambient pressure. This work offers insights into the reaction of carbides containing alkali metals and paves the way for the future investigation of high superconductivity in metal carbide systems.

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