2.2 DFT calculation
Surface
analysis and G solv of designed molecules were
calculated by DFT calculation. All electronic structures in this work
were conducted using the Gaussian 09 suite of the
program29. The designed molecules investigated were
fully optimized in the gas and solution phase by the B3LYP
/6-31G(d)30, 31, including empirical dispersion
corrections DFT-D3 method32, 33, and were performed
using the tight convergence criterion, which was always followed by the
calculation of harmonic vibrational
modes. To utilize the SMD model consistently, we have performed
calculations of G solv at the same levels of
theory utilized in the parameterization of SMD. We used M05-2X
exchange-correlation functionals34 along with 6-31G(d)
to calculate the single point energy in gas and water, which has proved
to be reliable for calculating the E ads andE sol35.G solv could calculate by the formula as follow:
where G solv is solvation free energy,E sol and E gas are the
single-point energy calculated by M05-2X/6-31G(d). Based on the
optimized molecular structures, the HOMO/LUMO electrostatic potential
(ESP) and molecular polarity index (MPI) were analyzed by the Multiwfn
program36 and visualized via the VMD
package37. All basis sets are obtained from the Basis
Set Exchange library.