Formation of Carbon Nanotube Based Gears: Quantum Chemistry and Molecular Dynamics Simulations of the Electrophilic Addition of o-Benzyne to Fullerenes, Graphene, and Nanotubes.


Richard Jaffe, NASA Ames Research Center and Jie Han and Al Globus, MRJ, Inc. at NASA Ames Research Center.


In accompanying papers [Han 96, Globus 96], the structure, operation, and properties of hypothetical nanotube-based molecular gears are described. These gears are single-walled carbon nanotubes with appended o-phenylene groups to serve as teeth. One possible synthetic route for the formation of these gears is the electrophilic cycloaddition of o-benzyne to the polycyclic aromatic nanotube. This reaction is known to occur under mild conditions with planar molecules such as naphthalene and anthracene [Hoffmann, 67] and fullerenes like C60 [Hoke 92]. In the present study we consider the pathways for o-benzyne addition to naphthalene, C60, and a model curved polycyclic aromatic hydrocarbons chosen to represent the carbon nanotube used in the gear simulations [Han 96]. We use Density Functional Theory (DFT), a variant of ab initio quantum chemistry, and molecular mechanics and dynamics calculations for this study. The molecular mechanics calculations are carried out using the potential energy force field developed by Brenner [Brenner 90]. The relative heats of reaction and reaction pathways are examined in an effort to determine whether this synthetic approach is feasible for the addition of o-phenylene groups to carbon-based nanotubes. In addition, we assess the suitability of the Brenner potential energy formulation for use in the companion molecular dynamics simulations [Han 96].

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To companion papers.

NAS Web Work: Al Globus