Covalent Sidewall Functionalization of SWNTs by Nucleophilic Addition of Lithium Amides

Abstract

The synthesis and characterization of sidewall‐functionalized SWNT derivatives (nPrNH)n‐SWNTs containing n‐propylamine addends is reported. The nucleophilic addition of in situ generated lithium n‐propylamide to the sidewall of SWNTs and the subsequent reoxidation of charged intermediates of the type (nPrNH)n‐SWNTn– leads to carbon nanotube derivatives with covalently attached amino groups. Based on the reaction sequence, a homogeneous dispersion of the carbon nanotube material is achieved as a result of the electrostatic repulsion of negatively charged intermediates. The solubility of the resulting propylamine‐functionalized (nPrNH)n‐SWNT material in organic solvents is drastically increased. The functionalized tubes were characterized in detail by Raman spectroscopy, thermogravimetric analysis (TGA/MS), X‐ray photoelectron spectroscopy (XPS) and UV/Vis/NIR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Coupled thermogravimetry, mass spectrometry, and infrared spectroscopy for quantification of surface functionality on single-walled carbon nanotubes

“…Using the mass after solvent desorption as the starting mass, the purified SWCNT show a weight loss of 5% following thermal desorption to 700°C. This result is consistent with other reports of thermal desorption measurements performed on purified SWCNT materials, which show weight losses in the range of 5-20% under similar conditions [19][20][21][22][23]. This suggests that there are low levels of adsorbates and/or functional groups present on the nanotubes after only the synthesis and purification steps, which is also consistent with observations made by other groups [7,11].…”

“…Exercising control over the oxidizing conditions affords some ability to differentiate between sample components [18]. More recently, TG has been applied under inert desorption conditions to monitor adsorbates and functional addends attached to CNT samples [19][20][21][22][23]. In the majority of such cases, it is assumed that the total loss in sample mass can be attributed entirely to the liberation of the specific functional moieties being studied, which then allows the estimation of the degree of functionalization.…”

A Novel Diameter‐Selective Functionalization of SWCNTs with Lithium Alkynylides

“…The subsequent reoxidation of the charged (pentyne) n -SWCNT n-intermediates by air yields neutral (pentyne) n -SWCNT derivatives, which exhibit pronounced dispersibility in organic solvents such as THF or o-DCB. In contrast to the corresponding reactions with alkylides [21,36,37] or amides, [38] lithium acetylide based reaction sequences require elevated temperatures. Therefore, in this study a variety of different solvents, for example, o-DCB, o-xylene or diglyme, were investigated to open a larger temperature window due to the higher boiling points of these solvents.…”

Resonance behavior of the defect-induced Raman mode of single-chirality enriched carbon nanotubes

“…The frequencies are represented by + and × signs, the intensities of the D mode contributions are indicated by the radii of the circles. The strongest D -mode intensity is observed, when the RBM of the (9,7) and (9,8) SWCNTs is in resonance. Unexpectedly, the well-known dispersion behavior of the D mode [13] is only observable above a certain excitation energy (1.7 eV for the SWCNTs in our sample).…”