Functionalization of carbon ad-dimer defective single-walled carbon nanotubes through 1,3-dipolar cycloaddition: a DFT study

• Published in: Structural chemistry 2015-04, Vol.26 (2), p.507-515
• Main Authors: Ghafouri, Reza, Ektefa, Fatemeh
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Computer Applications in Chemistry; Original Research; Physical Chemistry; Theoretical and Computational Chemistry
• ISSN: 1040-0400; 1572-9001
• DOI: 10.1007/s11224-014-0507-2

We have theoretically investigated the [2 + 3] cycloaddition reactions of the two types of 1,3 dipoles with carbon ad-dimer (CD) defective zigzag ( n , 0) Single-walled carbon nanotubes (SWCNTs), n  = 6, 7, and 8, in terms of geometry, energy, and electronic structure. The 1,3 dipoles have similar formula but different structures, consisting of the linear propargyl/allenyl anion and bent allyl anion dipoles. A CD defective SWCNT is formed by the adsorption of a carbon dimer which introduces two adjacent pentagons between two heptagons with the 7-5-5-7 arrangement; therefore, it seems this additional C = C unit on the surface of carbon nanotubes could be considered as preactivated sites for exohedral functionalization. Negative values of 1, 3 DC reaction energies ( E r ) indicate the exothermic character of the adsorption process of the CD defective SWCNTs. DFT results indicate that the 1,3 DC reactions of narrower CD defective SWCNTs with high curvature might be more favorable because of both energetic and structural considerations. Moreover, magnitudes of E r for the 1,3 DC reactions of the bent allyl anion type dipoles with the CD defective SWCNTs are always larger than those of linear propargyl/allenyl ones. HOMO–LUMO energy gaps ( E g ) for the 1, 3 DC products show a decreasing trend with the increasing tube diameter while almost independent of the types of the 1,3 dipoles. Graphical Abstract