Quantum Electronic Stability in Selective Enrichment of Carbon Nanotubes

Abstract

We have studied the structural and electronic stability of a helical ribbon of flavin mononucleotide wrapping around single-walled carbon nanotubes using first-principles density-functional calculations. The helical ribbon is formed through hydrogen bonding between adjacent uracil moieties of the isoalloxazine ring and stabilized through concentric pi-pi interactions. The electronic structure calculations reveal quantum electronic stability associated with lattice registry and band alignment between the helical assembly and the (8,6) nanotube. The electronic stability plays an essential role in the experimentally observed highly selective enrichment of specific chirality tubes.

Dispersion control and characterization in multiwalled carbon nanotube and phenylethynyl-terminated imide composites

“…Force-field-based molecular mechanics and density functional theory (DFT) calculations have shown that PETI-330 can wrap and form charge transfer complexes with carbon nanotubes providing a driving force for dispersion [28]. This result is qualitatively consistent with the study of other systems conducted by the same authors, such as a helical assembly of flavin interacting with carbon nanotubes [29] or polymers interacting with carbon nanotubes and graphene nanoribbons [30]. The results presented here indicated that some threshold of energy was required to attain homogeneous dispersion and distribution.…”

Isotopically Induced Variation in the Stability of FMN-Wrapped Carbon Nanotubes

“…For this, we employed the ideal helical wrapping of FMN around (8,6)-SWNTs, whose lateral stability is intimately coupled to the quadruple H-bonds responsible for forming the isoalloxazine ribbon, shown in Figure 1. [3,16,17,18] Depending on the surrounding solvent ( i.e. H 2 O vs. D 2 O), the facile proton-to-deuterium exchange of the imide group enabled us to alter the intermolecular surfactant-surfactant interactions, while keeping the overall 8/1 FMN-dimer helix virtually intact.…”

Handedness Enantioselection of Carbon Nanotubes Using Helical Assemblies of Flavin Mononucleotide

“…P- (8,6) and M -(6,8)), since our originally predicted structure of the 8/1 helix 5 showed good agreement with that from a more advanced DFT calculation. 11 This allowed us to incorporate periodic boundary conditions for both FMN and nanotube helices by slightly contracting ( ca. 5%) the 2.63 nm (8,6)-SWNT unit cell 13 to match the 2.5 nm helix period.…”

“…17 This trend is observed with increasing coverage, as shown by the Δω G+ ( hc − lc ) column in Table 1, despite an otherwise expected upshift due to FMN-induced nanotube p -doping. 11 In terms of radial breathing mode (RBM), nanotube torsion has been reported to upshift ω RBM . 17a This is witnessed with all resolvable ( n,m ) nanotubes in Table 1 (Figure S9), using the two laser lines that are above 600 nm to avoid FMN fluorescence.…”