Mahdiye Ghasemi - Department of Chemistry, Faculty of Science, Guilan University, Rasht, Iran
Mohammad Rizehbandi - Department of Chemistry, Faculty of Science, Guilan University, Rasht, Iran

In this study interaction of Busulfan anticancer drug with PEG-modified cellulose was investigated. The impacts of the stereo electronic effect associated with donor-acceptor electron delocalization, dipole-dipole interactions and total steric exchange energies on the structural and electronic properties and reactivity of modified cellulose in interaction with Busulfan anticancer drug was studied based on the Density Functional Theory (DFT) calculations by using B۳LYP/(۶-۳۱G, ۶-۳۱G*) level of theory in gas phase and water solution. Thermodynamic functional analysis indicates that the relative energies (ΔE), free Gibbs energies (ΔG) and enthalpies (ΔH) are negative for of Busulfan anticancer drug-PEG-modified cellulose system but the calculated entropies (ΔS) are Positive, suggesting thermodynamic favorability for covalent attachment of dye on PEG-modified cellulose and these results confirm the structural stability of the Busulfan in gas phases. Delocalization of charge density between the bonding or lone pair and antibonding orbitals calculated by NBO (natural bond orbital) analysis. The calculated LUMO-HOMO energy bond gap show that charge density transfer occurs within the molecules and the semi-conductivity of PEG could be justified.

Cellulose, PEG, Thermodynamic Functional, Delocalization