Figure 2.

IR spectra of (A) L-lysine, (B) H-Lys(Boc)-OH (starting material), (C) modified SWCNT-Lys-NH₂ and (D) unpurified SWCNTs provided by Sigma-Aldrich Corporation.

Notes: The black arrow identifies the carbonyl group from the Boc moiety when present. C-H stretches found in unpurified SWCNT represent amorphous carbon impurities prior to removal. A more complete analysis is found in Figure S5.

Abbreviations: IR, infrared; SWCNT, single-walled carbon nanotube; Boc (tert-Butyloxycarbonyl); Lys, lysine.