Do phenolic and carboxylic groups coexist at the tips of oxidized single-wall carbon nanotubes (o-SWNTs)?

Document Type

Article

Journal/Book Title

Carbon

Publication Date

1-1-2014

Volume

73

First Page

194

Last Page

205

Abstract

Vibrational frequency analyses using density functional theory (DFT) resolves some structural features of purified oxidized single-wall carbon nanotubes (o-SWNTs). Both single bondCOOH and phenolic single bondOH (OHph) groups, predicted in several experimental studies to be present in o-SWNTs, were considered at the tips of armchair and zigzag tubes with varying diameters. Hydrogen bonding, where carbonyl oxygen acts as proton acceptor while phenolic OH donates the proton, leads to the most stable isomers, with a H-bond energy of 9–12 kcal/mol, almost double that of simpler systems. Vibrational frequencies of participating bonds are significantly red-shifted, which is not reflected in experimental spectra, and which leads to the conclusion that phenolic OH is likely not present at the tips of o-SWNTs.

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