Computational details
MPBCP, [La-MPBCP]+3 and La-MPBCP complexes were
optimized using the density functional theory. Calculations in this
paper were performed with the Perdew-Burke-Ernzerhof
(PBE0-D3)39-40 functional and the def2-TZVP basis
set,41 using the Gaussian 09
program.42 In order to characterize all optimized
structures, we have computed their vibrational modes at the same level
of theory. Geometries from local minima were used to carry out their
respective NBO analysis, at the same level of
theory.43 The band gap of the system was calculated
from the difference between HOMO and LUMO orbitals. The adsorption
energy, Eads , is defined as the difference
between the sum of the energy of the isolated molecule gas and of
[La-MPBCP]+3 and La-MPBCP complex and the energy
of the system with a bonded gas molecule. Adsorption energy
(E ads) of different systems are calculated with
the following equation:
Eads (gas molecule) = E ([MPBCP] -gas
molecule) - (E [MPBCP] + E gas molecule)
Eads (gas molecule) = E([La-MPBCP]+3 -gas molecule) - (E[La-MPBCP]+3 + E gas molecule)
Eads (gas molecule) = E (La-MPBCP -gas
molecule) - (E La-MPBCP + E gas molecule)
Where E (E La-MPBCP or
[La-MPBCP]+3-gas molecule) is the total energy of
the system of E [La-MPBCP]+3 or ELa-MPBCP and gas molecules, and E[La-MPBCP]+3, La-MPBCP and E gas molecule
are the total energies of the functionalized structure with lanthanum
and a molecule of gas present, respectively.
The quantum molecular descriptors for
[La-MPBCP]+3, La-MPBCP consist of ionization
potential (I), electron affinity (A), global hardness
(η),44 electronegativity (χ), electronic chemical
potential (μ),45 electrophilicity index
(ω)46 and chemical softness (S) are calculated
according to follows equations: I = −EHOMO,A = −ELUMO, η = (I – A)∕2, χ= I + A∕2, µ = −(I +
A)∕2, ω= ‑ µ2∕2η and S = 1∕2η
All generated files from Gaussian 09 were analyzed with the Chemcraft
program v1.8