Patterns in Hydrogen Bonding: Functionality and Graph Set Analysis in Crystals

Abstract

Whereas much of organic chemistry has classically dealt with the preparation and study of the properties of individual molecules, an increasingly significant portion of the activity in chemical research involves understanding and utilizing the nature of the interactions bet w e n molecules. Two representative areas of this evolution are supramolecular chemistry and molecular recognition. The interactions between molecules are governed by intermolecular forces whose energetic and geometric properties are much less well understood than those of classical chemical bonds between atoms. Among the strongest of these interactions, however, are hydrogen bonds, whose directional properties are better understood on the local level (that is, for a single hydrogen bond) than many other types of nonbonded interactions. Nevertheless, the means by which to characterize, understand, and predict the consequences of many hydrogen bonds among molecules, and the resulting formation of molecular aggregates (on the microscopic scale) or crystals (on the macroscopic scale) has remained largely enigmatic. One of the most promising systematic approaches to resolving this enigma was initially developed by the late M. C. Etter, who applied graph theory to recognize, and then utilize, patterns of hydrogen bonding for the understanding and design of molecular crystals. In working with Etter's original ideas the power and potential utility of this approach on one hand, and on the other, the need to develop and extend the initial Etter formalism was generally recognized. It with that latter purpose that we originally undertook the present review.

Interconvertable Modular Framework and Layered Lanthanide(III)-Etidronic Acid Coordination Polymers

“…37 This unit constitutes the basis of the 2D network of water present within the interlayer space depicted in Figure 7b. Even though a number of recent reports describe various types of discrete water clusters (such as tetramers, pentamers, hexamers, octamers, decamers, dodecamers) and a few polymeric clusters (essentially infinite chains), complete crystallographic descriptions of highly ordered 2D aggregates of uncoordinated water molecules are much more scarce.…”

Even–odd effect in the co-crystals of pyrazine and dicarboxylic acids

“…Weak intra-chain C-HÁÁÁO hydrogen bonds within the chain are rather artefacts of the primary, strong interactions. Hereinafter, we will discuss the C-HÁÁÁO hydrogen bonds on the basis of both geometrical features and of their role on the crystal structure, either structure-directing or just mere secondary [35][36][37][38][39]. In the case of 1, the above-mentioned interactions are rather of secondary nature, but the interchain C-HÁÁÁO bonds (vide infra) are definitively playing important role in the building of crystal structure.…”

“…The dihedral angle between the ring planes-related by c-glide-in stack is as small as 3.4°, the inter-planar distance is 3.22Å with almost 35 % overlap between the aromatic pyrazine rings. Using the graph-set notation [38,39], the motifs of the structure can be described by C(10) \ R 2 2 (7) [ chains with second-rank intra-chain rings, while inter-chain weaker interactions would add R 2 2 (4), R 2 2 (8), and R 4 4 (10) rings, cf. Fig.…”

Redetermination of the crystal structure of 2-(thiomethyl)-benzo-1,3- thiazole at 200 K – Localization of hydrogen atoms, C8H7NS2

“…These are supportedbyone of thehydrogen atoms of the methyl group as donor and the intracyclic sulfur atom as acceptor. In terms of graph-set analysis [7,8], the descriptor for these contacts is C 1 1 (5) on the unary level. In total, the molecules are connected to infinte chains along the crystallographic c axis.…”