Crystal Engineering: Strategies and Architectures

Abstract

The area broadly described as crystal engineering is currently expanding at a brisk pace. Imaginative schemes for supramolecular synthesis, and correlations between molecular structure, crystal packing and physical properties are presented in the literature with increasing regularity. In practice, crystal engineering can be many different things; synthesis, statistical analysis of structural data, ab initio calculations etc. Consequently, we have been provided with a new playing field where chemists from traditionally unconnected parts of the spectrum have exchanged ideas, defined goals and made creative contributions to further progress not only in crystal engineering, but also in other disciplines of chemistry. Crystal engineering is delineated by the nature and structural consequences of intermolecular forces, and the way in which such interactions are utilized for controlling the assembly of molecular building blocks into infinite architectures. Although it is important to acknowledge that a crystal structure is the result of a subtle balance between a multitude of non-covalent forces, this article will focus on design strategies based upon the hydrogen bond and will present a range of approaches that have relied on the directionality and selectivity of such interactions in the synthesis of predictable one-, twoand three-dimensional motifs.

Crystal Engineering of the Coordination Architecture of Metal Polycarboxylate Complexes by Hydrothermal Synthesis: Assembly and Characterization of Four Novel Cadmium Polycarboxylate Coordination Polymers Based on Mixed Ligands

“…[8,14,32,56] Neither tp ligands nor bpp ligands bridging to the same Cd center are coplanar; the NϪCdϪN bond angle is 98.57 (12) come from a tetrahedral geometry rather than from a pseudo-octahedral geometry; 4-linking nodes of tetrahedral geometry usually result in adamantoid networks. Due to the NϪCdϪN bond angle of 98.57 (12)°and the flexibility of the bpp ligands, an interesting pipe-comb-like 2D layer structure with a channel of about 11.4 ϫ 11.1 Å occurs in this single 4 4 network along the ab plane (Figure 2). Moreover, the 4-linking nodes allow the 2D 4 4 network to have the undulating nature of the square grid polycatenated by another independent, symmetry-related 4 4 network, thus showing a twofold parallel interpenetration topology (Figure 3).…”

Simvastatin-nicotinamide co-crystal: design, preparation and preliminary characterization

“…A decrease in the melting point and heat content of the co-crystal will directly correlate to increased solubility of the API in the co-crystal. The melting point of the co-crystal would fall between the melting points of the API and its coformer [22]. X-ray powder diffraction is a specific technique to confirm whether the new solid state and the pharmaceutical co-crystal are prone to forming isostructural phases [23].…”

Supramolecular Assemblies in Salts of 2,2′‐Biimidazole with 5‐Sulfosalicylic Acid and 3,4,5‐Trihydroxybenzoic Acid

“…[1][2][3][4][5][6][7] The primary goal in this field is to control the way in which individual molecules are brought together into extended architectures in the solid state, allowing us to affect solid state reactivity, and to design new functional materials. The synthetic tools available for the construction of such assemblies are non-covalent forces, many of which are poorly understood and difficult to calculate and measure.…”