Computational insights into the coupling mechanism of benzoic acid, phenoxy acetylene and dihydroisoquinoline catalyzed by silver ion as polarizer and stabilizer

Abstract

The coupling mechanism of benzoic acid, phenoxy acetylene and dihydroisoquinoline in 1,4-dioxane was investigated in detail using the M06-L and M06-2X functionals. The barriers for the energetically more favorable pathway are 179.9, 85.4 and 82.7 kJ/mol. Ag + activates and polarizes the C ≡ C triple bond of phenoxy acetylene, and stabilizes the intermediate of α-acyloxy enol ester. NCI analyses demonstrate that the π-π stacking does not facilitate the coupling of benzoic acid and phenoxy acetylene. Due to the fact that α-acyloxy enol ester is naturally highly polarized, the subsequent addition of α-acyloxy enol ester and dihydroisoquinoline can occur without the aid of Ag +. The atomic polar tensor (APT) charge and fuzzy bond order (FBO) analysis reveal the variation of the two C-N bonds.

Isomerization energies and surface electrostatic potential analyses on nitriles and isocyanides

“…The gas-phase geometries of the selected R-C≡N and :C=N-R with 21 functional groups were fully optimized at B3LYP-D3(BJ)/def2-QZVP level with Gaussian 09 program package [11], and frequency verification was performed simultaneously to confirm local minima without imaginary frequencies, and to calibrate the thermodynamic parameters to 298.15 K. The traditional density functional of Becke's three-parameter nonlocal exchange functional [12] with the nonlocal correlation functional of Lee, Yang and Parr [13] (B3LYP) in combination with Grimme's Becke-Johnson-damping D3(BJ) dispersion correction [14] is an economical and highly efficient theoretical method, and can perfectly describe the possible noncovalent interactions such as intramolecular hydrogen bonding and weak electrovalent bonds in this work [15][16][17][18][19]. The quadruple zeta valence def2-QZVP polarized bases proposed by Weigend and Ahlrichs [20] were employed to accurately define the basis sets of these main-group elements.…”