Nanocomposites and nanomaterials

Electronic structure of fullerenes C60 complexes with thiochrome

Pavlenko O.L. 1, Busko T.O. 1, A. Davydenko1, Pundyk I.P. 1, КulishM.P. 1, Vovk A.I. 2, O.D. Kachkovsky2

1 Faculty of Physics, Taras Shevchenko National University of Kyiv, Prospect Glushkova, 4, Kyiv, Ukraine. 
E-mail: olpavl57@gmail.com 
2 Institute of Bioorganic Chemistry and Petrochemistry, NAS of Ukraine, Murmanska str, Kyiv-94,Ukraine.  

    In the near future the problem of early diagnosis of malignant tumors is perspective to be solved by the help of unique nanobiotechnologies. Depending on the localization of the tumors it is very important to deliver the drugs to damaged  organs. Among the potential promising and effective biomedical conveyors of pharmaceuticals the C60 molecule occupies an important place. However there are certain problems with broad prospects for the use of such substances for the prevention and treatment of diseases. One of the problems is that the fullerene molecule in the human body becomes almost imperceptible. It is impossible to trace where exactly it is and whether it got along with the medicine in the right place. We propose the use with fullerene C60 a thiochrome - biomolecule, which has an intense fluorescence to solve this problem. The possibility of the molecular complex formation, its structural features and its electronic structure were studied.
The complex fullerene C60 -thiochrome with stacking interaction was received in result of quantum-chemical calculations (semi-empirical AM1 method) of minimum of the potential energy. Optimized geometry of the complex is presented on Fig. 1.

Fig. 1. Optimized geometry of molecular complex fullerene C60 -thiochrome. 

Calculations show changes of charge distribution of molecules within complex compared to the single molecules, for the tiochrome it is shown on the fig.2. 

Fig. 2. Changes of charge distribution of tiochrome molecule within complex (curve 2, red circles) compared to the single molecule (curve 1, squares). 

Changes of the charge induced changes in the electron structure, HOMO-LUMO levels of the complex are different from the single molecules.