A two-layer method was used to study the reaction of nitric oxides with a 5-1DB defect on the side-wall of a single-walled carbon nanotube. A suitable ONIOM model was chosen for calculating the single-walled carbon nanotubes, based upon an analysis of the frontier molecular orbitals, local density of states and natural bond orbitals. The calculations clearly indicated that the 5-1DB defect was the chemically active center of the single-walled carbon nanotubes. In the reaction of nitric oxides with the defected single-walled carbon nanotube, the 5-1DB defect site could capture a nitrogen atom from nitric oxides, yielding N-substitutionally doped single-walled carbon nanotubes. The reaction pathway was explored in detail. This work verified the chemical reactivity of the 5-1DB defects of single-walled carbon nanotubes and indicated that the 5-1DB defect was a possible site for the functionalization of such nanotubes. The results indicated a possible way to fabricate position-controllable substitutionally-doped single-walled carbon nanotubes having a low dopant concentration under mild conditions via simple chemical reaction.

Chemical Reaction of Nitric Oxides with the 5-1DB Defect of the Single-Walled Carbon Nanotube. L.V.Liu, W.Q.Tian, Y.A.Wang: Journal of Physical Chemistry B, 2006, 110[5], 1999-2005