Precision Nanotube Mimics via Self-Assembly of Programmed Carbon Nanohoops

Abstract

The scalable production of homogeneous, uniform carbon nanomaterials represents a key synthetic challenge for contemporary organic synthesis as nearly all current fabrication methods provide heterogeneous mixtures of various carbonized products. For carbon nanotubes (CNTs) in particular, the inability to access structures with specific diameters or chiralities severely limits their potential applications. Here, we present a general approach to access solid-state CNT mimic structures via the self-assembly of fluorinated nanohoops, which can be synthesized in a scalable, size-selective fashion. X-ray crystallography reveals that these CNT mimics exhibit uniform channel diameters that are precisely defined by the diameter of their nanohoop constituents, which self-assemble in a tubular fashion via a combination of arene-pefluoroarene and C-H---F interactions. The nanotube-like assembly of these systems results in capabilities such as linear guest alignment and accessible channels, both of which are observed in CNTs but not in the analogous all-hydrocarbon nanohoop systems. Calculations suggest that the organofluorine interactions observed in the crystal structure are indeed critical in the selfassembly and robustness of the CNT mimic systems. This work establishes the self-assembly of carbon nanohoops via weak interactions as an attractive means to generate solid-state materials that mimic carbon nanotubes, importantly with the unparalleled tunability enabled by organic synthesis.

Perfect and Defective 13C-Furan-Derived Nanothreads from Modest-Pressure Synthesis Analyzed by 13C NMR

“…Carbon's ability to form highly directional bonds in several different hybridizations yields a diverse panoply of molecular frameworks in zero, one, two, and three dimensions, including adamantanes, 1, 2 fullerenes, 3,4 nanotubes, 5,6 nanohoops, [7][8][9] graphene, 10 graphane, 11,12 covalent organic frameworks, [13][14][15] and their ultimate ancestors graphite and diamond; these have garnered justifiably broad and deep interest in the scientific community. Saturated carbon nanothreads, which fill the one-dimension/sp 3 entry in this matrix of dimensionality and hybridization, were first synthesized by high-pressure solid-state polymerization of benzene.…”

Supramolekulare Bindungstaschen in [n]Cyclo‐2,7‐pyrenylenen

“…Es wurden mehrere weitere C‐H⋅⋅⋅O‐Wasserstoffbrücken zwischen den deutlich polarisierten C‐H‐Gruppen des Kronenethers als Wasserstoffbrückendonor und der Sauerstoffatome des Wirts 1 [5] als Wasserstoffbrückenakzeptor identifiziert (Abbildung S45). Die Kristallstruktur weist eine röhrenförmige Packung von 1 [5] auf, in der die Leerräume mit mit 18‐Krone‐6⋅K + und dem BF 4 − ‐Anion gefüllt sind und die entstehenden Säulenstapel der Struktur hexagonale Kreispackungsmotive bilden (Abbildung S42) [73, 74] …”

Theoretical Insights for Materials Properties of Cyclic Organic Nanorings

“…With this in mind, 10CPP and 12CPP bearing symmetrically placed tetrafluorophenylene moieties were recently synthesized and their X‐ray crystal structure fully resolved. [ 187,188 ] These molecules self‐assembled into perfectly aligned columns, creating accessible nanochannels mimicking actually those found in CNTs. The complementary theoretical analysis performed revealed the key intermolecular interactions contributing the most to this specific packing, not only between superimposed molecules (driven by complementary C–F⋅⋅⋅H interactions) but also between adjacent columns (driven by quadrupole–quadrupole interactions).…”