10.1021/acs.jpcc.6b10676.s001
Tapas Kar
Tapas
Kar
Upendra Adhikari
Upendra
Adhikari
Steve Scheiner
Steve
Scheiner
Ajit K. Roy
Ajit K.
Roy
Renato L. T. Parreira
Renato
L. T. Parreira
Pedro A. de S. Bergamo
Pedro A.
de S. Bergamo
Giovanni F. Caramori
Giovanni F.
Caramori
Felipe S. S. Schneider
Felipe S. S.
Schneider
Solvation Enhances the Distinction between Carboxylated
Armchair and Zigzag Single-Wall Carbon Nanotubes (SWNT-COOH)
American Chemical Society
2017
SLDB
acid groups
THF
solvent
COOH
cm
Zigzag Single-Wall Carbon Nanotubes
3LYP
DFT
lf-COOH
CS
SWNT-COOH
zigzag
SWNT
2017-04-11 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Solvation_Enhances_the_Distinction_between_Carboxylated_Armchair_and_Zigzag_Single-Wall_Carbon_Nanotubes_SWNT-COOH_/4905644
The
effect of various solvents on the structures and properties
of carboxylated SWNTs has been explored using the same level different
basis set approach (SLDB), where B3LYP functional of density functional
theory (DFT) was applied. Armchair (4,4) and zigzag (8,0) and (9,0)
tubes were considered as the testbed. In order to simulate varying
concentration of −COOH groups, one to five acids groups were
placed at one end of these tubes. These samples were placed in different
solvents (namely, CS<sub>2</sub>, THF, and water) with varying polarity
and results were compared with gas-phase properties. Similar to the
gas-phase, zigzag tubes also exhibit both regular (r-COOH, ν(CO)
above 1700 cm<sup>–1</sup>) and low-frequency (lf-COOH, ν(CO)
below 1700 cm<sup>–1</sup>) acid groups. Characteristics of
the r-COOH group are not affected much in solvents, but lf-COOH of
the zigzag tube is the one that makes these tubes distinguishable
from its armchair cousin. Stability and charge distribution of SWNT-COOH
strongly depend on the number of acid groups in different solvents
which may help controlling further functionalization. Vibrational
analyses reveal certain features in the 1400–1600 cm<sup>–1</sup> range that are characteristic of lf-COOH and in different solvents,
which may help in the assignment of experimental spectra of oxidized
SWNT in solvents.