Dynamic and static behavior of hydrogen bonds of the X-H center dot center dot center dot pi type (X = F, Cl, Br, I, RO and RR ' N; R, R ' = H or Me) in the benzene pi-system, elucidated by QTAIM dual functional analysis

摘要

Dynamic and static behavior of the X-H-*-pi interactions in X-H-*-pi(C6H6) (X = F, Cl, Br, I, HO, MeO, H2N, MeHN and Me2N) is elucidated by QTAIM-DFA (QTAIM dual functional analysis), which we proposed recenty, as the first step to clarify various types of X H-*-pi interactions. The asterisk * emphasizes the existence of the bond critical point (BCP) on the interaction in question. Total electron energy densities (H-b(r(c)) are plotted versus H-b(r(c)) V-b(r(c))/2 [=h(2)/8m)del(2)pb(r(c))] at BCPs in QTAIM-DFA, where V-b(r(c)) are potential energy densities at BCPs. In our treatment, data for the perturbed structures around the fuEly optimized ones are employed, in addition to those for the fuEly optimized structures. Data from the fuEly optimized structures are analyzed by the polar coordinate (R, 0) representation. Each plot for an interaction, containing data from the perturbed structures, shows a specific curve, which provides important information. The plot is expressed by (theta(p), kappa(p): theta(p) corresponds to the tangent line of the plot and kappa(p) is the curvature. theta and theta(p) are measured from the y-axis and the y-direction, respectively. WhiEe (R, theta) correspond to the static nature, (theta(p), kappa(p)) represent the dynamic nature of interactions. The nature of the X H-*-pi(C6H6) interactions is well specified by (R, theta) and (theta(p), kappa(p)). All interactions, examined in this work, are classified by the pure dosed shelE interactions and predicted to have the van der Waals nature.