Computational Organic Chemistry

Book Reviews
Computational Organic Chemistry, 2nd Edition; Bachrach, Steven M.; John Wiley & Sons, Hoboken, NJ, 2014: pp 1-632 + xiii, ISBN 978-1-118-29192-4 (hardcover), $125.

Even though he reported on the field via a blog in the 7 years since the first edition was published, the author decided to publish a welcome second edition. The key concept to both is the application of Quantum Mechanics (QM) for description of chemical reactions and properties. Use of these principles, aided of course by ever increasing computing power, is being used to determine details in both reactivity and structure determination of chemical compounds.  Much of the material has been updated including two new chapters on spectroscopy and enzymes.

The Preface is probably the best review of both the book and the field of computational organic chemistry, beginning with the history and rapid evolution of the field. For molecules the size and complexity of organic molecules, the fundamental Schrödinger equation (if solvable, the key to all molecular properties) cannot be solved exactly so a number of approximations are necessary to facilitate the process  For simplicity only ab initio methods (from basic principles) are considered which, given the continual increase in computing power, become increasingly practical. The ready availability of the number of computer programs also facilitates growth and practice.

The book is aimed both at existing or potential practitioners of computational chemistry and the latter can include both prospective occasional users or graduate students seeking an entry into the field. According to the author, prior expertise in quantum chemistry is not necessary to read the book but the QM taught in a typical undergraduate physical chemistry course should suffice. Chapter 1 is an introduction to the field, its concepts and definitions of the myriad abbreviations used. It can be used to better the understanding of subsequent chapters. Chapter 2 is on spectroscopy and the ability to use calculated spectra in structure determination. Chapter 3 is a brief introduction to several concepts of organic chemistry—including isomerism, acidity, and aromaticity—amenable to the application of computational studies.  Chapter 4 covers pericyclic reactions including my favorite, the Diels-Alder reaction. Radicals, and carbenes are covered in Chapter 5 and carbanions as well as organic catalysis in Chapter 6. Solvent effects are the subject of Chapter 7 and dynamic effects in reactions in Chapter 8. Although many biochemical molecules are too large for effective computation, the smaller molecules involved are covered in Chapter 9, the other new chapter.

The author emphasizes the personal aspects of the field. The first edition contained, at the end of several chapters, six interviews with a computational chemist working in that particular aspect, including the late Paul Schleyer. These are reprinted in this second edition and three additional interviews have been added. The book is lavishly illustrated, references are at the end of each chapter, and the index is extensive. The author maintains an associated website (www.comporgchem.com) to supply supporting information. In addition, the related blog (www.comporgchem.com/blog) will provide updates to the material in the book and is intended to serve a two-way function with reader comments welcome.

The reviewer’s educational background—50 years ago—and a math background that plateaued with an incomplete perception of matrices provides additional challenges for full comprehension. Nevertheless, I’ve developed an appreciation for what QM and computational chemistry can do for our understanding of chemistry.  I was especially pleased when, in both editions, the author described the controversy generated by Dewar 30 years ago that the mechanism of the Diels-Alder reaction was not concerted (i.e., that the formation of the new bonds was sequential and not simultaneous). However, Dewar was using semiempirical calculations whereas ab initio methods confirm other studies that the reactions are concerted and synchronous.  Other pericyclic reactions are also covered but I’m curious whether any computational work has been done on the related Ene reaction.

Why is this book being reviewed in the CIB?  It is a treatise in the broader field of chemical information, of value to others than practitioners.  Also the number of venues for book reviews in both chemical information and computational chemistry has become increasingly limited.  An additional disclaimer: I’ve known the author for 20 years and have found his contributions to our field of chemical information to be valuable. Recommended for the audiences described in the third paragraph.

Robert E. (Bob) Buntrock
Orono, ME
buntrock16@roadrunner.com