The linear relationship between Koopmans' and hydrogen bond energies for some simple carbonyl molecules

Abstract

Recentemente Galabov and Bobadova-Parvanova mostraram que a energia de formação da ligação de hidrogênio obtida por cálculo no nível HF/6-31G(d,p) está altamente correlacionada com o potencial eletrostático molecular na região aceptora em alguns compostos carbonílicos simples. Neste trabalho mostramos que o potencial eletrostático pode ser substituído pela energia de Koopmans. A correlação entre esta energia e a energia de formação da ligação de hidrogênio é tão alta quanto aquela observada por Galabov e Bobadova-Parvanova. O potencial de Siegabhn relacionando às energias de Koopmans e cargas GAPT mostra que a energia de ligação de hidrogênio não está simplesmente correlacionada com a carga da região aceptora pois as cargas dos átomos vizinhos são também importantes no processo de ligação de hidrogênio.Recently Galabov and Bobadova-Parvanova have shown that the energy of hydrogen bond formation calculated at the HF/6-31G(d,p) level is highly correlated with the molecular electrostatic potential at the acceptor site for a number of simple carbonyl compounds. Here it is shown that the electrostatic potential can be replaced by Koopmans' energy. The correlation between this energy and the hydrogen bond formation energy is just as high as the one observed by Galabov and Bobadova-Parvanova. The Siegbahn simple potential relating Koopmans' energies and GAPT charges shows that the hydrogen bond energy is not simply correlated with the charge of the acceptor site because the charges on the neighboring atoms are also important in the hydrogen bonding process.

DFT studies of camptothecins cytotoxicity III: camptothecin, irinotecan and SN-38

“…However, only negligible differences in individual atomic charges for all compounds can be concluded within the same popula-tion analysis (compare the average values in Table 1) as well. As shown by DFT calculations [Bruns et al, 2002;Urbic, 2014;Kochanek et al, 2015;Liao and Chu, 2015], H•••O hydrogen bond strengths increase with the negative charges of oxygen atoms, which implies that the strength of hydrogen bonding in ternary complexes with DNA and Topo 1 is preserved in all compounds under study. Subsequently, a Cu 2+ ion has been placed near individual heteroatoms (distance of approximately 1.7 Å was proven useful in our previous studies Breza, 2016, 2017;Jelemenska and Breza, 2021;Simon, 2019, 2020;Steklac and Breza, 2021a, 2021b, 2021c ing ones are presented in Figs.…”