2 nd Iranian Student Chemistry Conference University of Guilan, Rasht, 6-8 Oct. 2015 A theoretical study on structure and electronic properties of a fulleropyrrolidine dithiocarbamate derivative Ashkan Karimi a , Hadi Behzadi a *, Azim Ziyaei a a Department of chemistry, Kharazmi University, Tehran, Iran akarimi.chem@yahoo.com behzadi@khu.ac.ir Abstract: Medicinal applications of fullerenes and specially C 60 have attracted intense international interest due to their antiviral and antioxidant activity and ability for drug and gene delivery. Since fullerenes are hydrophobic, hydrophilic moieties are needed to attach to fullerenes for carrying drugs. 1 Furthermore size of C 60 is almost close to size of many biological molecules. 2 The cavity of HIV-1 protease active site is about 10 Å in diameter and is close to the diameter of C 60 . Two amino acids (Asp25 and Asp 125) in HIV-1 protease active site are hydrophilic which catalyzed the attack of water on HIV-1 protease. It has been shown that fullerenes derivatives can inhibit HIV-1 protease by making complex with it. 3 Fulleropyrrolidine are soluble derivatives of fullerene which have been found active against HIV and cancer. 4 In present Study a fulleropyrrolidine derivative [C 60 -C 2 H 4 N-CSSCH 2 CHOHCOOH] were studied. Dithiocarbamate was chosen because Pyrrolidine dithiocarbamate has antiviral activity. 5 Gaussian 03W suite of program was used to carry out a series of calculations. All calculations were done with hybrid B3LYP density functional and 6-31G (d) basis set. We studied all of the conformers and identified the lowest energy conformation. Various geometrical parameters, vibrational spectra, physical, chemical and thermodynamics properties of studied molecule are calculated. Positive vibrational spectra ensured that we obtained the optimized structure. Figure 1 shows geometry of optimized structure and hydrogen bonds. Vibrational position of C=O, shows a shift toward lower frequencies which is a result of hydrogen bonding in our system. Also NMR calculations show downfield shifting for resonance position of hydrogen. HOMO, LUMO and their energy gap were calculated and interaction energies were obtained to show strength van der Waals interactions. In comparison between heteroatom of O, S and Se, Sulfur shows unique properties. It has the highest dipole moment, strongest interaction and surprising electronic properties. According to high polarity and strong hydrogen bonding between our structure and two aspartic acid units, we evaluated this molecule as HIV-1 protease inhibitor.