Finite phenine nanotubes with periodic vacancy defects

Abstract

Discrete graphitic carbon compounds serve as tunable models for the properties of extended macromolecular structures such as nanotubes. Here, we report synthesis and characterization of a cylindrical C304H264molecule composed of 40 benzene (phenine) units mutually bonded at the 1, 3, and 5 positions. The concise nine-step synthesis featuring successive borylations and couplings proceeded with an average yield for each benzene-benzene bond formation of 91%. The molecular structure of the nanometer-sized cylinder with periodic vacancy defects was confirmed spectroscopically and crystallographically. The nanoporous nature of the compound further enabled inclusion of multiple fullerene guests. Computations suggest that fusing many such cylinders could produce carbon nanotubes with electronic properties modulated by the periodic vacancy defects.

Narrowing Segments of Helical Carbon Nanotubes with Curved Aromatic Panels

“…[5] This study demonstrated that amethod to narrow the chiral cylinders can be devised by adopting curved arylene panels in the Pt-mediated macrocyclization. [10][11][12][13][14][15]24,31] Width variations of the chiral molecular cylinders allowed us to deepen our understanding of their unique chiroptical properties. [18] Notably,atransient cyclic current can be induced on the chiral cylinders upon photo-excitation, which intensifies current-induced magnetic dipole moments in aw idth-dependent manner.…”

“…[11] Since the synthesis of the first congener of [N]cyclo-para-phenylenes ([N]CPP) reported in 2008, aseries of armchair segments with q = 308 8 has dramatically accumulated to cover N = 5-16, 18, 20, and 21, which expanded the structural library of molecular segments with this specific chiral angle. [4,12] Synthetically,t he armchair library was expanded by the advent of af ew privileged corner units such as ac yclohexadiene unit, which were accumulated by an umber of relevant papers. [4] Contrarily,s egments with chiral angles other than q = 308 8 are much less explored and still scarce.…”

Narrowing Segments of Helical Carbon Nanotubes with Curved Aromatic Panels

“…The chiral angle is 30° for armchair congeners and 0° for zigzag congeners, and their in‐between angles, 0°< θ <30°, are associated with helical congeners . Since the synthesis of the first congener of [ N ]cyclo‐ para ‐phenylenes ([ N ]CPP) reported in 2008, a series of armchair segments with θ =30° has dramatically accumulated to cover N =5–16, 18, 20, and 21, which expanded the structural library of molecular segments with this specific chiral angle . Synthetically, the armchair library was expanded by the advent of a few privileged corner units such as a cyclohexadiene unit, which were accumulated by a number of relevant papers .…”

“…In contrast to armchair CNT segments with a variety of [ N ]CPP‐like congeners, structural variations of helical CNT segments are much less explored, despite their unique chiral structures . This study demonstrated that a method to narrow the chiral cylinders can be devised by adopting curved arylene panels in the Pt‐mediated macrocyclization . Width variations of the chiral molecular cylinders allowed us to deepen our understanding of their unique chiroptical properties .…”

Supramolekulare Chemie von gespannten Kohlenstoffnanoreifen

“…Verbindung 2 (Abbildung ), für die eine Ringspannungsenergie von 120 kcal mol −1 abgeschätzt wurde, konnte aus einem Dodeca‐Brom‐Vorläufer in einem finalen Yamamoto‐Kupplungsschritt in 1 % Ausbeute erhalten werden . Jüngste Berichte über die Synthese von sesselförmigen‐ und chiralen Nanogürteln sowie eines Phenin‐Nanozylinders und eines lemniskularen CPP ‐Derivats deuten darauf hin, dass diese kurze geschichtliche Einführung der Nanoreifensynthesen noch lange nicht abgeschlossen ist. Eindeutig eine gute Nachricht für Forscher, die versuchen, diese Verbindungen als supramolekulare Wirte und für organische Materialien zu nutzen …”