| Autor: |
Stevenson S; Department of Chemistry, Purdue University Fort Wayne, Fort Wayne, Indiana 46805, United States., Liu X; Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States., Sublett DM Jr; Department of Geosciences, Virginia Tech, Blacksburg Virginia 24061, United States., Koenig RM; Department of Chemistry, Purdue University Fort Wayne, Fort Wayne, Indiana 46805, United States., Seeler TL; Department of Chemistry, Purdue University Fort Wayne, Fort Wayne, Indiana 46805, United States., Tepper KR; Department of Chemistry, Purdue University Fort Wayne, Fort Wayne, Indiana 46805, United States., Franklin HM; Department of Chemistry, Purdue University Fort Wayne, Fort Wayne, Indiana 46805, United States., Wang X; National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States., Huang R; Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States., Feng X; Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States., Cover K; Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States., Troya D; Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States., Shanaiah N; Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States., Bodnar RJ; Department of Geosciences, Virginia Tech, Blacksburg Virginia 24061, United States., Dorn HC; Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States. |
| Abstrakt: |
Although fullerenes were discovered nearly 35 years ago, scientists still struggle to isolate "single molecule" tubular fullerenes larger than C 90 . In similar fashion, there is a paucity of reports for pristine single-walled carbon nanotubes (SWNTs). In spite of Herculean efforts, the isolation and properties of pristine members of these carbonaceous classes remain largely unfulfilled. For example, the low abundance of spherical and tubular higher fullerenes in electric-arc extracts (<0.01-0.5%) and multiplicity of structural isomers remain a major challenge. Recently, a new isolation protocol for highly tubular fullerenes , also called f ullertubes, was reported. Herein, we describe spectroscopic characterization including 13 C NMR, XPS, and Raman results for purified [5,5] fullertube family members, D 5h -C 90 and D 5d -C 100 . In addition, DFT computational HOMO-LUMO gaps, polarizability indices, and electron density maps were also obtained. The Raman and 13 C NMR results are consistent with semiconducting and metallic properties for D 5h -C 90 and D 5d -C 100 , respectively. Our report suggests that short [5,5] fullertubes with aspect ratios of only ∼1.5-2 are metallic and could exhibit unique electronic properties. |
