title: Separation of semiconducting single-walled carbon nanotubes by using a long-alkyl-chain benzenediazonium compound.
abstract: We designed and synthesized 4-dodecyloxybenzenediazonium tetrafluoroborate (1), which preferentially reacts with metallic single-walled carbon nanotubes (SWNTs) by kinetic control. We first determined the suitable experimental conditions for the preferential reaction of 1 with individually dissolved SWNTs by monitoring the decrease in absorbance for the metallic SWNT in the range of 400-650 nm in the absorption spectrum of the SWNTs. The reacted SWNTs were thoroughly rinsed with THF to obtain THF-insoluble SWNTs. The Raman spectrum of the THF-insoluble SWNTs showed a strong peak near 180 cm(-1), which corresponds to a semiconducting breathing band. The metallic breathing bands (approximately 220 cm(-1)) and Breit-Wingner-Fano (BWF) modes (1520 cm(-1)) corresponding to the metallic SWNTs were much weaker than those of the pristine SWNTs. We also confirmed that metallic peaks in the range of 400-650 nm in the absorption spectrum of THF-insoluble SWNTs that were individually dissolved in an aqueous micelle of sodium cholate were almost nondetectable. All the results indicate that the THF-insoluble SWNTs are semiconducting.
authors: Department of Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
authors: Shouhei
authors: S
authors: Toyoda
authors: Yoshifumi
authors: Y
authors: Yamaguchi
authors: Masataka
authors: M
authors: Hiwatashi
authors: Yasuhiko
authors: Y
authors: Tomonari
authors: Hiroto
authors: H
authors: Murakami
authors: Naotoshi
authors: N
authors: Nakashima