Heck reaction on single-walled carbon nanotubes.: Synthesis and photochemical properties of a wall functionalized SWNT-anthracene derivative

Sidewall functionalization of single-walled carbon nanotubes (SWNTs) via the Heck cross-coupling reaction of pre-functionalized p-iodophenyl SWNTs allows the covalent binding of different groups such as alkyl chains, dialkylamino or anthracenyl moieties. Functionalized SWNTs were characterized by a set of methods including H-1 NMR, ATR-FTIR, XPS, UV/vis and Raman spectroscopic techniques. The degree of functionalization was estimated as 5.5 wt%. Laser flash photolysis studies comparing a covalently bonded anthracenyl derivative and mixtures of anthracene precursor and SWNTs revealed similarities between both systems (occurrence of photoinduced electron transfer, SWNT acting as electron acceptor) and differences (lifetimes of the charge separation), the charge separated state being much shorter lived for the system having covalent bonding with respect to the independent components.