Carbon nanotubes functionalizing amidation

Amide bond is an effective anchor to connect CNTs to substrate surfaces. Lan et al. [52] covalently assembled shortened multi-walled carbon nanotubes (s-MWNT) on polyelectrolyte films. The shortened MWNT is functionalized with acyl chloride in thionyl chloride (SOCl2) before self-assembling. The FTIR spectrum of self-assem-bled MWNT (SA-MWNT) adsorbed on a CaF2 plate modified with PEI/(PSS/PEI)2 shows two characteristic absorption peaks at 1646cm-1 (amide I bond) and 1524cm-1 (amide II bond) resulting from the amide bond formed between the polyelectrolyte films and s-MWNTs. 

In general, on chemical modification carbon nanotubes exhibit much less toxicity or nontoxicity to living cell lines that have been investigated so far.117,118 For instance, Dumortier et al. conducted an in vitro cell uptake study of the functionalized SWNTs with B and T lymphocytes and macrophages.117 Two types of functionalized SWNTs were used, one prepared via 1,3-dipolar cycloaddition reaction and the other obtained through oxidation/amidation treatment. Both types of the functionalized nanotubes were rapidly taken up by lymphocytes and macrophages without affecting the overall... 

The amine function served also as the starting point for the first covalent linkage of Pcs to single-walled carbon nanotubes (SWNTs) [94], The pipes with open-end and surface-bound acyl chloride moieties were used to prepare the Pc-SWNTs system by amide-bond formation (Fig. 14). Accordingly, statistical reaction of 4-aminophthalonitrile with 4-tcr/-bu(yIph111alonitrile in the presence of zinc ions delivered the monoamino Pc that was then employed in the conjugation with the acid chloride modified carbon nanotubes (CNTs). Here, it should also be mentioned that other functions have been applied to the covalent modification of CNTs, i.e., amide [95], ester [96,97], or click chemistry [98],... 

An attachment of structures bearing isocyanate groups by amide bonding is feasible, too. However, a diisocyanate is employed here with one of its functional groups being converted into an amide with the carboxyl group. Carbon nanotubes are thus modified suitable for the preparation of nanotube-polymer composites, especially of the polyurethane type. 

In general, functionalization reactions of SWNTs are very slow and take several days to proceed. In this respect, microwave irradiation seems to be a potentially powerful tool to functionalize SWNTs but only a few such reactions have been described to date. One example of the application of microwaves was described by Della Negra et al. [88]. Soluble single-walled carbon nanotubes were synthesized by grafting poly(ethylene glycol) (PEG) chains on to SWNTs. Use of microwave irradiation enhanced reaction rates in comparison with similar syntheses using conventional heating. An amidation reaction has also been performed, in two steps, under microwave irradiation conditions (Scheme 21.23) [89]. Amide-SWNT derivative 68 was synthesized by reaction of 2,6-dinitroaniline and the carboxylic acid-... 

Mallakpour S, Zadehnazari A. One-pot synthesis of glucose functionalized multi-walled carbon nanotubes dispersion in hydrox-ylated poly(amide-imide) composites and their thermo-mechanical properties. Polymer 2013 54(23) 6329-38. 

Mallakpour S, Zadehnazari A. Efficient functionalization of multi-walled carbon nanotubes with p-aminophenol and their application in the fabrication of poly(amide-imide)-matrix composites. Polym Int 2013. 

Mallakpour S, Zadehnazari A. The production of functionalized multiwall carbon nanotube/amino acid-based poly(amide-imide) composites containing a pendant dopamine moiety. Carbon 2013 56 27-37. 

Zhou G J, Wang S F, Zhang Y, Zhuang Q X and Han Z W (2008) In situ preparation and continuous fiber spinning of poly(p-phenylene benzobisoxazole) composites with oligo-hydroxy-amide-functionalized multi-walled carbon nanotubes, Polymer 49 2520-2530. 

The combination of bromine and sodium methoxide has been used to effect the HR of amide- to amino-functionalized single-wall carbon nanotubes.Azasteroid 73 yields lactam 74 on treatment with bromine/sodium methoxide,and amide 75 produces BOC-protected amine 76 with bromide and sodium tert-butoxide. ... 

Immobilisation of boronic acids on high surface area materials such as multi-walled carbon nanotubes with exposed carboxylate functional groups either via a single coupling step" or via dual coupling steps to form amide bonds (see Figure 8.6A and B) can provide electrode material with high sensitivity and selectivity towards ort/to-quinols such as dopamine. 

Multifunctionalized Carbon Nanotubes Polymer Composites 4.1.2 CNTs Amidation Functionalization... 

Carbon nanotubes 1. Mostly used carbon nanomaterials 2. Be easily covalently or non-covalently functionalized Oxidized CNTs can be grafted via creation of amide bonds, N2-plasma and radical addition SPE, MSPE, SPME, LDI substrate, p-SPE, SRSE 9 9... 

One of the first examples of the grafting to approach was published by Sun et al. in 2001 [32]. In this work carboxylic acid groups on the nanotube surface were converted into acyl chlorides by refluxing the samples in thionyl chloride. Then the acid chloride functionalized carbon nanotubes were reacted with hydroxyl groups of dendritic PEG polymers via esterification reactions. Similarly, many polymers terminated with amino or hydroxyl moieties have been used in amidation and esterification reactions with acid chloride modified NTs poly(propionylethylenimine-co-ethylenimine) (PPEI-EI) [33], poly(styrene-co-aminomethylstyrene) (PSN) [34], poly-(amic acid) containing bithiazole rings [35], monoamine-terminated poly(ethylene oxide) (PEO) [36], poly(styrene-co-hydroxymethylstyrene) (PSA) [37], poly(styrene-co-p-[4-(4 -vinylphenyl)-3-oxabutanol]) (PSV) [38], poly(vinyl alcohol) (PVA) [39], poly(vinyl acetate-co-vinyl alcohol) (PVA-VA) [40] or poly[3-(2-hydroxyethyl)-2,5-thienylene] (PHET) [41]. 

Using a glass carbon electrode (GCE) modified with MWCNTs, Cai et al. ° observed an enhanced sensitivity for electrochemical DNA biosensor based on CNTs. Figure 6.22 schematically shows the steps for constructing the nanotube-DNA biosensor. To start, carboxylic acid functionalized MWCNTs (COOH-MWCNTs) were dropped on a GCE electrode, single-strand DNA oligonucleotides (ss-DNAs) were then covalently bonded onto the COOH-MWCNTs via amide formation. The hybridization reaction on the electrode was monitored by differential pulse voltammetry (DPV) using an electroactive daunomycin intercalator as the indicator. 

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