molecular modeling of 13 c nmr chemical shifts in selected fullerenes

MOLECULAR MODELING OF 13C NMR CHEMICAL SHIFTS IN
SELECTED FULLERENES
Michał Stachów1, Marzena Nieradka1, Teobald Kupka1 and Leszek Stobiński2
1
2
University of Opole, Faculty of Chemistry, 48, Oleska Street, 45-052 Opole, Poland;
Institute of Physical Chemistry, Polish Academy of Sciences, 44/52, Kasprzaka Street,
01-224 Warsaw, Poland
Fullerenes and carbon nanotubes (CNTs) are novel systems [1,2] with potential
applications as nanocomposites, drug carriers, and in photodynamic therapy (PDT).
Unfortunately, no chemical synthesis method leading to a single product exists. The
commercially available materials are mixtures with high degree of amorphous carbon and
remaining metal catalyst.
Due to many problems in experimental characterization of carbonaceous materials at
atomistic level no reliable NMR studies of such samples are available. Thus, microscopic
and Raman techniques are the main tools used for their characterization [3].
Just recently, a first successful (three-step) synthesis of carbon nanotube tip was reported
by Scott and coworkers [4]. The product was soluble in common organic solvents and
formed crystals characterized by X-ray technique. In addition, the 13C NMR spectra of the
product were obtained in solution and the corresponding signal assignments were reported
[4].
As continuation of our earlier systematic theoretical studies on NMR parameters of model
SWCNTs [5] we selected several fullerenes and optimized their structures. In this paper we
analyze theoretical 13C NMR isotropic nuclear magnetic shielding constants and chemical
shifts of selected fullerenes and their derivatives. Our theoretical chemical shifts reasonably
reproduce recently reported experimental 13C NMR spectra of single wall carbon nanotube
tip in solution.
C60 „tip”
REFERENCES:
[1] H. W. Kroto, J.R. Heath, S. C. O’Brien, R. F. Curl, R. E. Smalley, Nature 318 (1985) 162.
[2] S. Iijima, Nature 354 (1991) 56.
[3] R. Saito, M. S. Dresselhaus, G. Dresselhaus, Physical Properties of Carbon Nanotubes, Imperial College
Press, London, 1998.
[4] L.T. Scott, E.A. Jackson, Q. Zhang, B. D. Steinberg, M. Bancu, B. Li., J. Am. Chem. Soc. 134
(2012)107.
[5] T. Kupka, M. Stachów, M. Nieradka, L. Stobiński, Magn. Reson. Chem. 49 (2011) 549.
Michał Stachów and Marzena Nieradka are recipients of a Ph.D. fellowship from a project funded by the
European Social Fund „Uniwersytecki Program Stypendialny 2012-2013” - Investing in scientific structure
by self - gevernment of the Opole Voivodeship. T. Kupka was financed within 8/WCH/2012-S grant.