Adsorption of Melphalan on the Surface of Single-Walled Carbon Nanotube: A DFT Study

In this study, adsorption of melphalan on the surface of single walled carbon nanotube was studied computationally. For this purpose, the structures of carbon nanotube, melphalan and the derived products from the interaction of melphalan with carbon nanotube at two different configurations were optimized geometrically. Then, IR and frontier molecular orbital calculations were implemented on them in the temperature range of 298-398 K at 10˚ intervals. The obtained thermodynamic parameters including Gibbs free energy changes (ΔGf) and formation enthalpy alterations (ΔHf) have revealed that the adsorption of melphalan is exothermic, spontaneous, one-sided and experimentally feasible at the both evaluated configurations. The influence of temperature on the thermodynamic factors of the desired process was also inspected and the results indicate that 298.15 K is the best temperature for the carbon nanotube substitution on melphalan. The calculated specific heat capacity values have shown that the sensitivity of the produced carbon nanotube- melphalan derivatives to the heat and shock have declined significantly. Some HOMO-LUMO related parameters such as energy gap, electrophilicity, chemical hardness, maximum transferred charge index (ΔNmax) and chemical potential were also calculated and discussed in details.