Study on dichlorocarbene cycloaddition isomers of armchair single-walled carbon nanotubes

Armchair single-walled carbon nanotubes with the various length and diameter, along with their dichlorocarbene cycloaddition isomers were optimized by AM 1 and PM3 methods. Nanotube with larger diameter has less strain force and a relatively strong pi-conjugated interaction. For short carbon nanotubes and the edge region of the long carbon nanotubes, dichlorocarbene cycloaddition can form both open and closed isomers on the horizontal and slopy C-C bond, respectively. In the middle of the relatively long nanotubes, dichlorocarbene cycloaddition can only form Horizontal-open and Slopy-closed isomers. The Horizontal-open isomer is more stable than other isomers thermodynamically in any case. The calculated infrared spectra are useful to determine whether the reaction between carbon nanotube and dichlorocarbene has taken place. (C) 2002 Elsevier Science B.V. All rights reserved.