Paul Schleyer: Among the last of the universalists

I was saddened to hear of the passing of Paul Schleyer, not exactly a household name among non-chemists but someone who was undoubtedly one of the most prolific and towering chemists of his time. Schleyer started out in synthetic physical organic chemistry and then moved to computational and theoretical chemistry. Starting out at Princeton, he moved to Erlangen in Germany and finally settled down at the University of Georgia, helping to make each one of these centers a leading hub for theoretical chemistry.

Schleyer was definitely one of the last universalities - at least in the theoretical territory of chemistry - and had a definitive grasp of almost every aspect of the field; from NMR spectroscopy (he came up with the valuable NICS metric for chemical shifts) and ab initio quantum chemical calculations to non-classical carbocations, lithium compounds and strained hydrocarbon synthesis (he synthesized adamantane, for instance). Most people are content to be experts in one or two fields, but it's probably not an exaggeration to say that Schleyer was close to being an expert in most of these fields. During his career he also seems to have co-authored papers and books with virtually every prominent figure in the field, from George Olah to John Pople to Jack Roberts. His publications on these and other parts of chemistry were prolific and deep, and he was also not one to shy away from spirited debate. I had the pleasure of watching him give a talk once and it was clear that he was a formidable opponent whose knowledge of chemistry would almost always supersede that of his 'adversaries'.

In fact that last aspect of his personality was on full display the first time I encountered him. This was as a graduate student when I came across a charming and very readable account of his debate with Herbert Brown on the infamous and invaluable non-classical carbocation debate. Titled "The Non-Classic Ion Problem", this little book is structured as a series of points and counterpoints in every chapter offered by Schleyer and Brown. The constant back and forth, the dissection of minutiae of solvents, reaction rates and spectroscopy, and the general unyielding yet cordial personalities of the two men are fascinating to watch. It's pure, unadulterated scientific debate at its best.

Schleyer was definitely one of the last and greatest practitioners of the golden era of physical organic chemistry, a time when chemists dedicated their lives to exploring the fundamentals of chemical reactions and structure with vigor and rigor. He is one of a handful of figures on whose shoulders we all stand and will be genuinely missed.