New Synthetic Routes to Introduce Sp 3-Defects in Carbon Nanotubes with a Variety of Functional Groups

Abstract

The controlled functionalization of single-walled carbon nanotubes (SWNTs) with luminescent sp 3-defects has emerged as a powerful tool to enhance their usually low photoluminescence quantum yields and has created the potential to employ them for bioimaging and optical sensors. For that, it is necessary to match and adapt the substituents of the sp 3-defects to the desired application. To attach a large variety of complex substituents to sp 3-defects an universal approach is required. Here, we introduce sp 3-defects to polymer-wrapped (6,5) SWNTs via diazonium salt chemistry [ACS Nano 2021, 15, 5147–5157] bearing an alkyne moiety and subsequently add the desired substituent by click-chemistry. This opens up the possibility to introduce many different functional groups such as stable organic radicals, photosensitizers or fluorophores, which are already available for click-reactions. This approach is not limited to E11* defects introduced by diazonium chemistry, but can be further extended to more red-shifted E11*− defects [Nat. Commun. 2021, 12, 2119].