Chloride ions as integral parts of hydrogen bonded networks in aqueous salt solutions: the appearance of solvent separated anion pairs

Abstract

Hydrogen bonding to chloride ions in various aqueous environments has been discussed many times over the past more than 5 decades. Still, the possible role of such hydrogen bonds (HB) in networks of HB-s has not been investigated at any detail. Here we consider computer models of concentrated aqueous LiCl solutions and compute usual HB network characteristics, such as distributions of cluster sizes and of cyclic entities, for the models by taking and not taking chloride ions into account. During the analysis of hydrogen bonded rings, a significant amount of 'solvent separated anion pairs' have been detected at high LiCl concentration. It is demonstrated that including the halide anions into the network does make the interpretation of structural details significantly more meaningful than when considering water molecules only. Finally, we compare simulated structures generated by 'good' and 'bad' potential sets on the basis of the tools developed here, and show that this novel concept is, indeed, helpful from this respect, too.

Layer-by-Layer Cell Encapsulation for Drug Delivery: The History, Technique Basis, and Applications

“…For LbL multilayers with PDADMAC and PAA, when the ionic strength was elevated to 0.6 M, disassembly of LbL films took place [199]. Similarly, hydrogen bond-based encapsulation could also be tuned by the addition of salt solutions [200].…”

D-Mannosamine hydrochloride (2-amino-2-deoxy-D-mannose hydrochloride): ionic hydrogen bonding in saccharides involving chloride and aminium ions

“…These results show that the hydrogen-bonding structure around Cl À can vary widely, with the present work providing examples of a trigonal planar geometry and a geometry resembling that found around a distorted tetrahedral C atom. These saccharide-based models of Cl À hydrogen bonding may provide useful insights into non-bonded interactions that occur in Cl À -containing ionic liquids and concentrated aqueous chloride salt solutions (Pethes et al, 2020), and during saccharide-receptor binding mediated by a bound Cl À anion.…”

“…Ionic hydrogen bonds are hydrogen bonds that form between ions and molecules and have strengths in the range 5-35 kcal mol À1 (Mautner, 2005). Ionic hydrogen bonding occurs in ionic liquids (Pethes et al, 2020) and has been implicated in biological processes, including enzyme catalysis and energetics (Yang & Castleman, 1991;Warshel & Russell, 1986). In serine proteases, for example, an anionic carboxylate side chain of an aspartic acid (Asp) residue is hydrogen bonded to the imidazole N atom of a histidine (His) residue in the catalytic triad to enhance the basicity of the imidazole ring (Warshel & Russell, 1986;Cleland et al, 1998).…”

Structural and Transport Properties of Binary Mixtures of Deep Eutectic Solvent (Ethaline) with Primary Alcohols: A Molecular Dynamics Study

“…Average number of H-bond was computed according to geometry based calculations [38,39], where a hydrogen bond was identified when donor and acceptor atom exists within a cutoff of angle 30 • and a maximum distance of and chloride ion (as acceptor) were calculated and observed to be the highest among other types of H-bond(see Figure 7). It is quite interesting to note that upon increasing the concentration of alcohol, the H-bond per unit donor molecule (i.e.…”