Analysis of Functionalization Degree of Single-Walled Carbon Nanotubes Having Various Substituents

Abstract

Introducing substituents onto SWNT sidewalls increases their solubility and tunes their properties. Controlling the degree of functionalization is important because the addition of numerous functional groups on the sidewall degrades their intrinsic useful electronic properties. We examined the synthesis and characterization of sidewall-functionalized SWNTs in this study. The functionalized SWNTs ((1)R-SWNTs-(2)R) were prepared in a one-pot reaction of SWNTs with alkyllithium ((1)RLi) followed by alkyl bromide ((2)RBr). The functionalized SWNTs were characterized by the absorption and Raman spectroscopy and thermogravimetric analysis. Not only the total number of functional groups introduced on the SWNT sidewall (formula mass: (1)R = (2)R) but also the ratio of (2)R to (1)R in the functionalized SWNTs (formula mass: (1)R ≠ (2)R) having two different substituents were clarified using the relation between results of Raman spectroscopy and thermogravimetric analysis. Results show that the degree of functionalization of (2)R to (1)R in (1)R-SWNTs-(2)R can be well controlled by the bulkiness of the alkyl groups of (1)RLi and (2)RBr. Moreover, substituent effects of reductive alkylation and reductive silylation of SWNTs via Birch reduction were investigated.

Defluorination-assisted nanotube-substitution reaction with ammonia gas for synthesis of nitrogen-doped single-walled carbon nanotubes

“…In contrast, the R value of the F-SWCNTs was 0.923 ± 0.042; further, the peak related to the radial breathing mode (RBM) could not be detected. It has been reported that an increase in the intensity of the D-band occurs not only owing to an increase in the number of topological defects in CNTs [23] but also owing to an increase in the number of sp 3 -hybridized covalent bonds formed by the CNTs [55][56][57][58]. In this study, the fact that the observed R value was high indicated that all the fluorine groups associated with the CF 0.39 stoichiometry were introduced to the nanotubes and that they bonded with the C tube atoms of the nanotube frame through sp 3 -hybridized covalent bonds.…”

Control of the photoluminescence properties of single-walled carbon nanotubes by alkylation and subsequent thermal treatment

“…[16] Meanwhile, we have previously reported that the substituents on SWNTs, and their bulkiness, strongly affect the degree of functionalization during the reductive alkylation of SWNTs. [20,21] Thus, we envisage the reductive alkylation with the appropriate choice of substituents, can be used to control the PL properties of SWNTs. Herein, we report the PL properties of dialkylated SWNTs with varying degrees of functionalization.…”

“…Dialkylated SWNTs (R 1 -SWNTs-R 2 ) were synthesized using butyllithium (R 1 Li) and butyl bromide (R 2 Br) according to previously reported methods. [20,21] (Scheme 1) In nBu-SWNTs-R (R = nBu, isoBu, secBu, and tBu) and tBu-SWNTs-R (R = nBu, isoBu, and secBu), the characteristic E 11 and E 22 absorption peaks were mostly diminished by the alkylation, indicating sidewall functionalization proceeded effectively. On the other hand, the absorption spectrum of tBu-SWNTs-tBu exhibited relatively small changes, as shown in Fig.…”

Versatile Two‐Step Functionalization of Nanocarbons: Grafting of Propargylic Groups and Click Post‐Functionalization

“…We decided to exploit the two‐step nucleophilic addition of organolithium compounds and electrophile capture grafting . This method has already been used for the trapping of different electrophiles, either alkanes for dispersion purposes or other dead‐end moieties . We, hereby, propose the use of a new, easily accessible, cheap, and atom‐efficient electrophile: propargyl bromide (Scheme ).…”

“…Such bundles affect their solubility in most organic solvents and water.T herefore, the race forn ew functionalization protocols featuring high loading, reproducibility,r obustness, andh omogeneityo ff unctions is still on, especially in the case of graphene.W ed ecided to exploit the two-step nucleophilic addition of organolithium compounds and electrophile capture grafting. [12][13][14] This methodh as already been used for the trapping of different electrophiles, either alkanes for dispersion purposes [15,16] or other dead-endm oieties. [14,[17][18][19][20][21] We, hereby, propose the use of an ew,e asily accessible, cheap,a nd atomefficient electrophile:p ropargyl bromide (Scheme1).…”