Interplay between dihydrogen and alkali–halogen bonds: Is there some covalency upon complexation of ternary systems?

Bent's Rule Contextualizes Hydrogen Bond Strength in Trimolecular Clusters

“…64 Mesmo que as variações para o vermelho e para o azul já tenham sido identificadas experimentalmente, 65 a análise vibracional harmônica certifica se o sistema intermolecular está devidamente caracterizado em uma região de mínimo global na superfície de energia potencial, e isto pode ser evidenciado pela estabilização e força de interação. Na prática, existem ligações de hidrogênio que apresentam uma tendência de caráter covalente, 18,66 embora também hajam casos 37,67 que a covalência é redundante e o sistema é estabilizado por uma força de ligação intermolecular tão elevada que se assemelha às energias das ligações químicas p ou σ.…”

Theoretical estimation of pnicogen bonds and hydrogen bonds in small heterocyclic complexes: Red-shifts and blue-shifts ruled by polarization effects

“…On considering that such a concept may be feasible, it appears that several intermolecular phenomena could be more easily understood [3][4]. After more than one century of research [5], the hydrogen bond is undoubtedly one of the most interesting intermolecular interactions [6], although other no less important types have been discovered and even proposed, such as the dihydrogen bonds [7][8][9][10][11][12], halogen bonds [13], and hydride-halogen bonds [14]. Even though the hydrogen function as an intermolecular mediator is well known [15], the challenge of uniting these interactions into one single intermolecular definition is not a simple task given that there are many different proton acceptors, e.g., the halogen atoms [16][17], lone pairs of electrons [18][19][20][21], π bonds [22][23], and hydride bonds [24][25].…”

“…Firstly, the characterization of both PN-Bonds and H-Bonds as closed-shell interactions is verified by means of the positive values of ∇ 2 ρ. Furthermore, the noncovalent character of these interactions is demonstrated by the positive values of H as well as the -G/U ratios being higher than 1[14,39], with values of 1.1162 (I),1.0379 (II) and 1.0793 (III). A direct relationship can be observed between the distances and electronic densities of the PN-Bonds of I and II.…”

Comparisons between Crystallography Data and Theoretical Parameters and the Formation of Intramolecular Hydrogen Bonds: Benznidazole

“…In regards to the remaining hydrogen bonds, all of them are non-covalent. However, besides the hydrogen bonds, 1T also reveals the formation of a dihydrogen bond [59][60][61] …”