Water Clusters in Crystal: Beyond the “Hydrogen‐Bonding Graphs”

Abstract

Supramolecular assembly: The ordered tetrahydrate of piperidine‐2‐carboxylic acid (see figure) is analysed using X‐ray diffraction with topological analysis of the electron density distribution function. This highly accurate method probes both the cooperativity effects of H‐bonding and the influence of solute on water molecule aggregation in these polyhydrates.

Cation–π and Lone Pair–π Interactions Combined in One: The First Experimental Evidence of (H3O‐lp)+⋅⋅⋅π‐System Binding in a Crystal

“…At the same time, their oxygen atoms are more negatively charged than those in potassium oxonium bis(hydrogensulfate) [16] and bear about À1.3 e, which is very close to the value for a water molecule (i.e. À1.4 e), [37] thus causing the oxonium cations in 1 to resemble neutral water-like species.…”

“…[36] In the AIM classification, all these interactions (see Table S1 of gies (E int ) were quantified using Espinosa's correlation [25,26] based on the XRD data, which allows the strength of both H bonds (whether classic or ionic) [23,37] and weak interactions [27,29] in a crystal to be assessed accurately. According to the values obtained (see Table S1 of the Supporting Information), the H 3 O + ···p interaction in 1 is rather weak, with the energy at 1.2 kcal mol…”

Hydrogen‐Bond‐Induced Inclusion Complex in Aqueous Cellulose/LiOH/Urea Solution at Low Temperature

“…The structure of water and the peculiarities of hydrogen bonding in crystal hydrates of organic compounds have attracted great attention, and the investigation of supramolecular organization in crystals of polyhydrates is currently a hot topic. [4,5] Understanding and predicting the properties of supramolecular assemblies of water molecules at a nanometer scale is a real scientific challenge for all scientists. [6] In chemistry, guest water clusters are very often found trapped within supramolecular host architectures; [6] hydrogen-bonding interactions between a perylene derivative and perylene bisimide has induced the self-assembly of a film with a cathodic photocurrent response; [7] hydrogen-bonded layer-by-layer films assembled from poly(vinylpyrrolidone) and poly(acrylic acid) change from cloudy to transparent upon annealing in acidic water.…”

Pseudosymmetry in Trinitropyrazole: The Cost of Error in Space‐Group Determination

“…Nevertheless, the pseudosymmetry between them is reflected in the total energy of the interactions of the independent species with the crystal environment ( Table 1). The corresponding values were obtained from the X-ray diffraction data by using the Espinosa correlation, which is equally valid for hydrogen bonds [15,16,18] and weak interactions; [19,20] the energy of the intermolecular interactions in TNP varies in the ranges 4.9-6.0 and 0.3-2.5 kcal mol À1 .…”