When dithiafulvenyl functionalized π-conjugated oligomers meet fullerenes and single-walled carbon nanotubes

Abstract

A series of π-conjugated oligomers taking linear and Z-shaped molecular structures were synthesized with electron-donating dithiafulvenyl (DTF) groups functionalized at the terminal positions. Besides significantly enriched electronic and redox properties as disclosed by UV-Vis absorption and voltammetric analyses, these DTF-endcapped oligomers also exhibited a facile reactivity of oxidative CC bond cleavage sensitized by fullerenes under air, converting the non-fluorescent DTF–oligomers to highly fluorescent aldehyde-endcapped oligomer products. This reaction provides an appealing approach for efficient fluorescence turn-on sensing of fullerenes. Furthermore, the DTF-attached oligomers showed strong noncovalent interactions with single-walled carbon nanotubes (SWNTs) to form soluble supramolecular assemblies in certain chlorinated organic solvents such as methylene chloride and chloroform. The dispersion of SWNTs effected by the DTF–oligomers was found to be highly efficient (up to 0.29 mg of SWNTs per mL) and shows selectivity for small-diameter nanotubes. The resulting SWNT suspensions could be easily dissociated upon addition of hydrocarbon solvents such as hexanes, releasing pristine SWNTs which were free of oligomer dispersants after filtration and solvent rinsing.