Crystalline C ₃ N ₃ H ₃ tube (3,0) nanothreads

Abstract

Significance The diamond nanothread is predicted to have comparable or larger strength and stiffness than the carbon nanotube but severely suffers from intrathread bonding disorder in practice. Here, we synthesized a bulk crystalline diamond nanothread material C 3 N 3 H 3 with a C/N-ordered tube (3,0) structure via high-pressure topochemical polymerization of s -triazine. The π-stacked s -triazine experienced a selective concerted bonding of three neighbored C···N pairs, completely different from the classical Diels–Alder reactions of aromatics under high pressure. This study obtained the structure-specific diamond nanothread with an unambiguous elemental reaction, which is the basis to realize the expected excellent properties of diamond nanothreads. Following the identified reaction selectivity under high pressure, more structure-specific carbon materials can be designed.

Ordered Van der Waals Hetero-nanoribbon from Pressure-Induced Topochemical Polymerization of Azobenzene

“…As shown in Table S4, 13 compounds with content greater than 1% were detected. Aniline (58.41%) is the decomposition product, which is also common in the HRGC-MS experiments of other C–N polymer systems . Several typical compounds that were recognized in the National Institute of Standards and Technology (NIST) database are shown in Figure a.…”

“…The selected area electron diffraction (SAED) pattern of poly-azobenzene indicated that these peaks are from the same phase, and indexed using a 2D-lattice with a = 7.67 Å, c = 27.13 Å, and β = 123.5° (Figure b). The ordering of b -axis was not found after many attempts, which is also a typical feature for the assembly of most nanothreads and nanoribbons. ,− , …”

“…Pressure-induced polymerization (PIP) is a successful method for preparing carbon-based materials with extended structures − and has demonstrated its adaptability in the preparation of graphane, , ultra-thin diamond nanothreads, − nanoribbons, as well as graphite–diamond composites. − Most PIP reactions proceed via a topochemical route, and the structure of the final product was highly related to the intermolecular conformation of its precursors . That means, the molecular stacking is the key to determine the structure of the synthesized materials.…”

Pressure-Induced Polymerization of Crystalline and Amorphous 3-Nitrophenylacetylene

“…Research on PIP has made remarkable progress in recent years. This solid-state polymerization method tended to study the critical structure of a monomer (usually a thermodynamic equilibrium phase) under specific pressure and temperature for precisely controlled synthesis of new carbon materials. , Several kinds of unsaturated molecules were chosen to synthesize high-density carbon materials with covalent-bond chains, such as benzene, , pyridine, − furan, phenol, triazine, and phenylacetylene derivatives. − In these cases, these samples were compressed and very slowly decompressed to maintain thermodynamic equilibrium, which sometimes needed tens of hours for an ordered structure. To obtain the specific structure, means such as optical excitation, temperature control, and changing the decompression rate have been used, but the monomer phase before the polymerization has been rarely changed.…”

Synthesis and Post‐Processing of Chemically Homogeneous Nanothreads from 2,5‐Furandicarboxylic Acid**

“…Since the initial formation of polymeric nanothreads through the slow, anisotropic compression of benzene, 17 several synthetic strategies have been developed to limit the number of potential reaction pathways and promote the formation of chemically homogeneous products through selective cycloaddition. [18][19][20][21][22][23][24] As the backbones of nanothreads extend in only one direction, these ultrathin carbon materials are predicted to marry the superlative physical properties of diamond with the flexibility of traditional polymers. [25][26][27][28][29][30] The chemical composition of nanothreads can be precisely controlled through careful selection of small molecule precursors (e.g., benzene, 17,31 pyridine, 32 pyridazine 23 ), giving them potential advantages over comparable nanomaterials (e.g., nanotubes).…”