Crystal engineering: Strategies and architectures

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-, two-and three-dimensional motifs.