Reinterpreting π-stacking

Abstract

The nature of π–π interactions has long been debated. The term "π-stacking" is considered by some to be a misnomer, in part because overlapping π-electron densities are thought to incur...

Simplified tuning of long-range corrected density functionals for use in symmetry-adapted perturbation theory

“….. As the number of rings increases, the Kohn-Sham gap for these one-dimensional acene nanoribbons decreases much faster as compared to that of their saturated (cyclohexane-based) analogues, the perhydroacenes. 52 Figure 1 compares tuned values ω IE and ω GDD obtained for acenes with up to to 40 rings, demonstrating that both tuning procedures predict an optimal value of ω that decreases monotonically with system size. In the context of IE tuning, similar trends with increasing system size have been noted previously for conjugated π systems, 42,[53][54][55] for linear alkanes, 42 for pentacene/C 60 clusters, 56 and for (H 2 O) − n clusters.…”

Electrostatics, Charge Transfer, and the Nature of the Halide–Water Hydrogen Bond

“…Only at long range, where the nuclei of each molecule are better screened by their respective electron distributions, is a multipolar picture recovered. Note that "charge penetration", meaning deviations from multipolar electrostatics engendered by interpenetration of ρ A (r) and ρ B (r), should not be confused with CT. 83 The latter effect, which is discussed below, arises from density relaxation in the presence of the other monomer, whereas the densities used to compute E elst are those of the isolated monomers.…”

Coordination chemistry of polynitriles. Part 9. Decacyanoferrocene revisited: crystal and molecular structure of cis-[{C5(CN)5}2(MeCN)4Fe]

“…The pentacyanocyclopentadienyl rings stack viainteractions (Carter-Fenk & Herbert, 2020;Thakuria et al, 2019), with the ring planes at a typical distance of ca 3.36 A ˚. A closer look (Fig.…”