Separation of metallic SWNTs and semiconducting SWNTs

Very recently, considerable attention has been focused on the separation of metallic SWNTs and semiconducting SWNTs. The combination of the chemical modification and physical adsorption on SWNTs has reported to be quite useful for the separation. Strano et al. reported an interesting method to separate metallic and semiconducting SWNTs. The separation is based on the difference in the reaction rates of 4-chlorobenzenediazonium tetrafluoroborate toword metallic-SWNTs and semiconducting SWNTs that are dissolved individually in an aqueous micelle of sodium dodecylsulfate. That is, under controlled conditions, tetrafluoroborate reacts with metallic-SWNTs selectively and by a thermal treatment of the reacted SWNTs, the pristine electronic structure of the nanotubes restored. We have modified their methods. That is, we designed and synthesized a double-chain benzenediazonium tetrafluoroborate, 1. We describe here the separation of metallic SWNTs and semiconducting SWNTs using compound 1.