OICC Press Journal of Nanostructure in Chemistry 2193-8865 6 1 (March 2016) 2015 12 07 Survey of quantum mechanic calculations on combination of carbon nanotube and Methotrexate drug 10.1007/s40097-015-0181-y EN F. Najafi Department of Chemistry, Roudehen Branch, Islamic Azad University, Roudehen, IR K. Zare Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, IR Journal Article 2015 12 07 Abstract The combination of a carbon nanotube and Methotrexate (an ordinary form of anticancer drug) was investigated based on the Hartree–Fock theory calculations in the gas phase, water and ethanol environment. Thermodynamic functions including Gibbs free energy, entropy, enthalpy changes were computed at different temperatures. We found a relation between dipole moment of the solute and dielectric constant of the solvent. The Gibbs free energy of solvation is reduced by increasing the dielectric constant of solvents.