Moreover, the electrons were transferred from the σ- orbital of the C-O bond (σ C-O) and the lone pair orbital of O (LP O) to the antibonding orbitals of B-C bond (σ* B-C) with the energy of 0.63 and 11.08 kcal/mol respectively. In the complexes of CNTs, the electrons were transferred from the σ- orbital of the C-C bond (σ C-C) to the antibonding orbitals of CO molecule (σ* C-O) with the energy in the range of 1.31-8.33 kcal/mol. Furthermore, the electrons were donated from the lone pair orbital of O (LP O) and the lone pair orbital of CO molecule (LP C(CO)) to the antibonding orbitals of C-C bond (σ* C-C) with the energy of 7.77 and 1.87 kcal/mol respectively.