Crystal Engineering: From Molecule to Crystal

TLDR

Crystal engineering seeks to understand how molecular aggregation in solution leads to crystal formation, the relationship between molecular and crystal structures, polymorphism, and solvent inclusion. The paper aims to guide crystal design by outlining how to achieve desired topologies, coordinations, or properties, exploring structure–property relationships, and charting future directions. It reviews the historical development of crystal engineering and highlights the supramolecular synthon as a key concept for practical crystal design.

Abstract

How do molecules aggregate in solution, and how do these aggregates consolidate themselves in crystals? What is the relationship between the structure of a molecule and the structure of the crystal it forms? Why do some molecules adopt more than one crystal structure? Why do some crystal structures contain solvent? How does one design a crystal structure with a specified topology of molecules, or a specified coordination of molecules and/or ions, or with a specified property? What are the relationships between crystal structures and properties for molecular crystals? These are some of the questions that are being addressed today by the crystal engineering community, a group that draws from the larger communities of organic, inorganic, and physical chemists, crystallographers, and solid state scientists. This Perspective provides a brief historical introduction to crystal engineering itself and an assessment of the importance and utility of the supramolecular synthon, which is one of the most important concepts in the practical use and implementation of crystal design. It also provides a look to the future from the viewpoint of the author, and indicates some directions in which this field might be moving.