Investigation of hydrogenated HiPCo nanotubes by infrared spectroscopy

Two different reductive synthetic methods were applied to hydrogenate the sidewalls of HiPCo single‐walled carbon nanotubes (SWNTs). In the first one, the reductive agent was melted potassium which doped and exfoliated the nanotube bundles, so that before hydrogenation all of the tubes had been converted to metallic ones. In the second method, doping occurred just before hydrogenation by naphthalenide radical anions. The products were characterized by wide range infrared (30–52 000 cm−1) spectroscopy with special emphasis on the selectivity of the two methods. We found that in the first case the controlling factor is the bandgap, and in the second case the diameter. This difference suggests the importance of the π–π interaction between naphthalenide and the nanotube surface.