Crystal Engineering: A Textbook

  • Gautam R. Desiraju,
  • Jagadese J. Vittal &
  • Arunachalam Ramanan
IISC PRESS AND WORLD SCIENTIFIC PUBLISHING: 2011. 216 pp. £65.00

Once upon a time, a certain well-known editor of a certain high-profile journal opined on the subject of crystal structure prediction by asserting that it was scandalous that solid-state chemists and materials scientists could not predict crystal structures from a priori knowledge of chemical composition (J. Maddox, Nature 335, 201; 1988). Just one year later, almost as if in response, Gautam Desiraju's book titled Crystal Engineering: The Design of Organic Solids (Elsevier, 1989) was published.

In hindsight, these two events were watershed moments for the immediate and rapid development of crystal engineering, which, it should be noted, overlaps very little with crystal structure prediction. Rather, crystal engineering focuses on the synthesis of new classes of crystalline materials from first principles through a strategy that uses molecules as if they were Lego building blocks. Desiraju's definition of crystal engineering was apt in 1989 and it has stood the test of time well: “understanding of intermolecular interactions in the context of crystal packing and utilization of such understanding in the design of new solids with desired physical and chemical properties”.

It would be fair to assert that there was not a lot of respect for crystal engineering back then. Indeed, most chemists and materials scientists would have considered even the idea of crystal engineering to be an oxymoron as crystals were generally regarded as being a consequence of 'nature abhors a vacuum', and unusual features of crystal structure were often explained away as being 'the result of crystal packing effects'.

Credit: © WORLD SCIENTIFIC

What has happened since is crystal clear: crystal engineering has facilitated the rapid development of new classes of compound that have practical utility, such as porous coordination polymers — aka metal–organic frameworks (MOFs) — and pharmaceutical co-crystals, which today represent two of the most active, high-impact areas in chemistry. Pictured is MOF-5, in which ZnO4 tetrahedra are linked together by benzene dicarboxylate ligands, forming an extended 3D network with accessible pores.

Crystal engineering has reached the 'end of the beginning'.

A sign that crystal engineering has come of age was the holding of the first Gordon Research Conference on crystal engineering in June 2010. This meeting boasted the highest ever first-time attendance for a Gordon Conference and demonstrated that crystal engineering covers all types of molecular building block, that it is international in scope and that it has reached the 'end of the beginning' as crystal engineers have developed a powerful toolbox in the context of crystal design. The focus has naturally shifted from design to properties, and this means that there is now a need for crystal engineering to be more broadly taught and not just to the next generation of crystal engineers.

The second sign of the coming of age of crystal engineering is represented by the publication of the first textbook devoted to the subject. Crystal Engineering: A Textbook was released on 28 June 2011 at the 20th International Conference on the Chemistry of the Organic Solid State (ICCOSS XX) in Bangalore, India. It is appropriate that the book was released at an international meeting held in India because the authors are native Indians, and India has been at the cutting edge of crystal engineering research for more than two decades.

As the title indicates, Crystal Engineering: A Textbook aims to serve as an introductory textbook rather than a reference book. It comprises seven well-balanced chapters, each of which concludes with a set of problems that are suitable for use in teaching. The first chapter provides a historical perspective that covers the development of crystal engineering and of cognate areas such as X-ray crystallography, supramolecular chemistry and properties of crystals. This chapter reminds us that the foundations of crystal engineering were not laid in 1989, and ensures giants such as Schmidt, Dunitz, Kitaigorodsky, Pauling and Wöhler receive appropriate credit.

Chapters 2–4 are titled 'Intermolecular Interactions', 'Crystal Design Strategies', and 'Crystallization and Crystal Growth', respectively. These chapters provide the background knowledge that is needed to practice crystal engineering and could stand alone for use in other courses. Chapters 5–7 cover three subjects of topical importance to contemporary materials science and are titled 'Polymorphism', 'Multi-Component Crystals' and 'Coordination Polymers', respectively. These chapters make extensive use of case studies to highlight concepts and define nomenclature, but not in a manner that takes sides where there is ambiguity about terminology. The book concludes with a glossary of terms, a tabulation of crystallographic space groups, a list of useful websites and a list of recommended reading. The latter is of note because citations are otherwise absent.

The length of Crystal Engineering: A Textbook, its modest price, its fair and balanced treatment of topics, and its breadth and style make it perfectly suited to serve as a one-semester course to introduce crystal engineering to undergraduate or first-year graduate students in chemistry or materials science. It effectively addresses a need that has been created by the explosive growth of crystal engineering research in the past two decades.