Sensing properties of light-emitting single walled carbon nanotubes prepared via click chemistry of ylides bound to the nanotube surface

Pyridinium ylide functionalized single-walled carbon nanotubes (SWCNTs) generated from simple quaternary pyridinium salts covalently bound to the SWCNT surface undergo a 1, 3 dipolar cycloaddition with dimethyl acetylenedicarboxylate in a 'click' chemistry type fashion to yield indolizine modified light-emitting SWCNTs. Conversion of quaternary pyridinium salts into indolizines on the SWCNT surface was confirmed by XPS, fluorescence spectroscopy and optical microscopy. The resulting modified SWCNTs were found to emit blue light when excited at 330 nm. Fluorescence quenching experiments performed via nitroaromatic compounds displayed that the fluorescence of the modified SWCNTs was quenched by nitrophenol derivatives in both solution-state and solid-state, probably due to strong H-bonding interaction between host and guest molecules. The functionalized SWCNTs were further characterized using TGA-MS, FTIR and UV-vis-NIR spectroscopy.