NBO analysis
We investigated the most important interaction between the gas molecules with the lanthanum, through an NBO analysis, in order to know more in detail their bond nature.
The study of natural bond orbitals shows the O, N atoms and H-H, C-H bonds, of the gas molecule participate as donors, while the lanthanum atom of La-MPBCP or [La-MPBCP]+3 systems as acceptor. Table 2 show stabilization energies, for donor and acceptor orbitals for all systems. The stabilization energy es mayor para [La-MPBCP]+3 and the order of E(2) is the following N2 > CO2>H2 > CH4.