A nitrogen-doped nanotube molecule with atom vacancy defects

Abstract

Nitrogen-doped carbon nanotubes have attracted attention in various fields, but lack of congeners with discrete molecular structures has hampered developments based on in-depth, chemical understandings. In this study, a nanotube molecule doped periodically with multiple nitrogen atoms has been synthesized by combining eight 2,4,6-trisubstituted pyridine units with thirty-two 1,3,5-trisubstituted benzene units. A synthetic strategy involving geodesic phenine frameworks is sufficiently versatile to tolerate pyridine units without requiring synthetic detours. Crystallographic analyses adopting aspherical multipole atom models reveal the presence of axially rotated structures as a minor disordered structure, which also provides detailed molecular and electronic structures. The nitrogen atoms on the nanotube serve as chemically distinct sites covered with negatively charged surfaces, and they increase the chance of electron injections by lowering the energy levels of the unoccupied orbitals that should serve as electron acceptors.

Geodesic Phenine Frameworks

“…The synthesis of (12,12)-pNT was concisely accomplished in 9 steps from 1,3-dibromobenzene ( Figure 7). After converting 1,3-dibromobenzene to 1,3-diborylated benzene (16), we synthesized a terphenyl derivative (18) that was further transformed into [6]CMP 19 via macrocyclization in a [3 + 3] fashion. The linker units of (pinacolato)boryl were then installed using direct C-H borylation reactions.…”

“…The linker units of (pinacolato)boryl were then installed using direct C-H borylation reactions. The cyclization of [6]CMP hexagons was achieved using Yamago's Pt-mediated macrocyclization with our boryl route modifications 17,21 to afford a cyclic synthetic intermediate, [4] We owe a debt, in a sense, to one reviewer who questioned the "synthetic generality" of our pNT synthesis, which stimulated the preliminary synthesis of the (9,9)-and (15,15)-pNT molecules (26 and 27) ( Figure 7). Thus, it took one additional month for an undergraduate student to complete the synthesis.…”

“…[60]fullerene as a reference. 1,2,3,4,6 A flatland of aromatic compounds can be enriched with curvatures created by nonhexagonal polygons such as pentagons and heptagons. 7,8 For instance, with [n]circulenes, a pentagon at the center results in a bowl-shaped molecule (n = 5; corannulene), 9 and a heptagon at the center results in a saddleshaped molecule (n = 7) 10 ( Figure 2).…”

“…16 The shape of GPF molecules was diversified to include cylinders/tubes by introducing Pt-mediated coupling reactions adopted for the macrocyclization, 17,18 and a recent example of an N-doped nanotube molecule demonstrated the versatility of the phenine strategy to include heteroatoms. 6 Another unique feature of GPFs is the presence of "defects", and the syntheses/structures of each GPF molecules will be detailed below. In this Account, we use the symbol "Φ" to indicate phenine, which should allow us to show the number of phenine panels without counting.…”

Recent advances and attempts in synthesis of conjugated nanobelts

“…Very recently, essentially the same synthetic route was used for synthesis of a nitrogen‐doped Type‐II nanobelt. [ 49 ]…”