New method for the calculation of bond native polarity using molecular electronic energy

Generation of Chemical Transformations: Reaction Pathways Prediction and Synthesis Design

“…The methods implemented in the Beppe program to evaluate the reactivity are based on the calculations of atomic and molecular properties of reactants, defined in the frame of the density functional theory, including electronic energies, electronegativities, hardness, and other related reactivity descriptors [93,94]. They are used to select the reactive sites in the reactants and evaluate the imaginary intermediate, interpreted as an approximated model of the transition state.…”

Prediction of Organic Reaction Products: Determining the Best Reaction Conditions

“…In principle, any mathematical combination is allowed; we chose a linear combination after an accurate analysis of different alternatives with respect to the better or worse representation of experimental behaviors. A complete description of their calculation can be found in previous papers, 6,11,12 but, to permit a qualitative understanding, we will briefly describe the equations used for their calculation.…”

“…where Q i and Q j are atomic charges, Rcov i and Rcov j are covalent radii, and the sum concerns all the bonded atom pairs; the two terms are evaluated using the charge distribution 14 on the products and on the reactants, respectively. elstatic where E i is the energy of each atom calculated using the formula 12 where k 1 and k 2 are constants depending on the atom type, (Z 0 )*′ is the effective nuclear charge of the isolated atom for a complete electron shielding, and Rcov 0 is the covalent radius of the isolated atom. N is the atomic number; N 1 , N 2 , and N 3 are the shell occupation numbers.…”

“…In principle, any mathematical combination is allowed; we chose a linear combination after an accurate analysis of different alternatives with respect to the better or worse representation of experimental behaviors. A complete description of their calculation can be found in previous papers, ,, but, to permit a qualitative understanding, we will briefly describe the equations used for their calculation where Q i and Q j are atomic charges, Rcov i and Rcov j are covalent radii, and the sum concerns all the bonded atom pairs; the two terms are evaluated using the charge distribution on the products and on the reactants, respectively…”

“…It is evident that both the selection of reactive bonds and the acquisition of the products is regulated by the calculation of physicochemical descriptors. They are mainly as follows: the bond polarity 10 and the bond hardness 11 for the selection of reactive bonds; the molecular electronic energy, 12 the imaginary intermediate (see below) electronic energy, the electrostatic potential, the molecular hardness, for the selection of the products. In addition, the program includes a second analysis level that, after an accurate analysis of the first level products, selects those suitable for a further reaction and applies the procedure again.…”