Functional Macromolecules from Single‐Walled Carbon Nanotubes: Synthesis and Photophysical Properties of Short Single‐Walled Carbon Nanotubes Functionalised with 9,10‐Diphenylanthracene

Abstract

9,10-Diphenylanthracene (DPA), a well-studied organic chromophore (Phi(fl) = 0.98) that exhibits electroluminescence, has been covalently bound through 2-(ethylthio)ethylamido linkers to the carboxylic acid groups of short, soluble single-walled carbon nanotubes (sSWNTs) of 1 microm average length, and the resulting DPA-functionalised sSWNT (DPA- sSWNT) macromolecular adducts (4.6 wt % DPA content) characterised by solution (1)H NMR, Raman and IR spectroscopy and thermogravimetric analysis. Comparison of the quenching of DPA fluorescence (steady-state and time-resolved) and of the transient optical spectra of sSWNTs and DPA-sSWNTs show that the covalent linkage boosts the interaction between the DPA and the sSWNT units. DPA-sSWNTs exhibit emission in the near-IR region from 1100-1400 nm with an enhanced quantum yield (Phi = 5.7x10(-3)) compared with sSWNTs (Phi = 3.9x10(-3)).

Photoinduced Formation and Characterization of Electron–Hole Pairs in Azaxanthylium‐Derivatized Short Single‐Walled Carbon Nanotubes

“…These short CNTs are remarkably soluble in water and in organic solvents and are susceptible to functionalization through the carboxyl groups present at their tips and wall defects. [17,18] The strategy used here to functionalize short CNT with 2-azaxanthone is shown in Scheme 1. The key steps in the synthesis are 1) the preparation of thiol-modified short CNTs (SH-CNT) through a peptidic bond; 2) 2,2'-azobisisobutyronitrile-initiated radical-chain addition of the thiol groups of SH-CNT to a terminal C=C double bond of N-undecenyl-2-azaxanth-N-ylium compound 2, which was obtained by treating 2azaxanthone (1) with 11-bromo-1-undecene.…”

“…The SH-CNT was prepared according to reported procedures, [2,17,19] and chemical analysis showed the expected 1:1 nitrogen:sulfur atomic ratio and a thiol loading corresponding to 3.15 wt % of the solid. Synthetic intermediate 2 was characterized by analytical and spectroscopic techniques, and the data agreed with the proposed structure (see the Supporting Information).…”

“…[15] Although the photochemistry of CNTs in the presence of non-bonded molecules may be similar to that of covalently functionalized analogues, it has been found that linking the two subunits increases remarkably the interaction between the components. [17] Since xanthone derivatives are among the best studied molecules in photochemistry, [7,8] and considering potential applications Abstract: 2-Azaxanthone, a nitrogenated derivative of the well-studied organic chromophore xanthone, has been covalently bound through 2-(ethylthio)ethylamido linkers to the carboxylic acid groups of short, soluble single-walled carbon nanotubes (CNTs) of 450 nm average length, and the resulting azaxanthylium-functionalized CNTs (AZX-CNT, 8.5 wt % AZX content) characterized by solution 1 H NMR, Raman and IR spectroscopy and thermogravimetric analysis. Comparison of the quenching of the triplet excited state of AZX (steady-state and time-resolved) and of the transient optical spectra of CNTs and AZX-CNT shows that the covalent linkage boosts the interaction between the azaxanthylium moiety and the short CNT units.…”

Rationalization and In Vitro Modeling of the Chemical Mechanisms of the Enzymatic Oxidation of Phenolic Compounds in Planta: From Flavonols and Stilbenoids to Lignins

“…However we have recently succeeded in providing credible 1 H NMR data in support of the covalent functionalization 41. 42 Furthermore, besides the complex 2.0–3.5 ppm region assigned to solvents, the 1 H NMR spectrum of Ru‐SWCNT shows the disappearance of the vinylic hydrogens present in the Ru complex used as the precursor and notable variations in the aromatic region. The inset of Figure 6 shows a comparison of the aromatic region of the solution 1 H NMR spectrum of the vinylic Ru complex precursor and the resulting Ru‐SWCNT.…”

Two‐Photon Chemistry in Ruthenium 2,2′‐Bipyridyl‐Functionalized Single‐Wall Carbon Nanotubes

“…However we have recently succeeded in providing credible 1 H NMR data in support of the covalent functionalization. [41,42] Furthermore, besides the complex 2.0-3.5 ppm region assigned to solvents, the Altogether the characterization data presented above indicates that the Ru-SWCNT sample under study is constituted of highly soluble, short nanotubes, which have covalently attached ruthenium complex units (15.6 %).…”