The atomistic details of the interaction between polycyclic and heterocyclic anticancer drug, realistic model for drug delivery by quantum mechanical modeling Criteria are developed and discussed that lead to the design of a new polycyclic and heterocyclic anticancer drug, which should have low toxicity but high biological selectivity and activity when attacking the DNA of tumor cells. Study of structural and thermodynamic properties of some polycyclic and heterocyclic Alkanes in proton affinity reaction using quantum mechanic methods are the main purposes of this thesis. Some structural parameters such as bond length, bond Angle and torsion Angle and some thermodynamic parameters such as enthalpy, Gibbs free energy, thermal energy was calculated using primary calculations of (HF) and density functional theory (DFT) with basis sets of 6-311++G** and 6-31G**and comparison between stability of reactants and products was carried out using applied thermodynamic parameters and principles of quantum mechanic such as maximum hardness principle (M.H.P) and minimum electrophilicity principle (M.E.P). Obtained results show that calculation of thermal energy is more appropriate than other thermodynamic parameters since in calculation of enthalpy and Gibbs free energy with two methods of HF and B3LYP and two applied basis sets, none of products were more stable than reactants but in calculation of thermal energy all products were more stable with all methods and basis sets. In using of maximum hardness principle, B3LYP method is more appropriate than HF Method since its influence from base set is less and shows more stable products. For minimum electrophilicity principle, choosing the HF method is better than B3LYP method with 6-311++G** base set since more molecule would be stable.
