The Record Breakers

L ast year, the Chemical Abstracts Service reached a remarkable milestone, as it added the 100 millionth compound to its vast registry. And the pace of synthesis is accelerating: Three-quarters of those were logged in the past decade alone. Although each compound is unique, a few stand above the rest. These are the record breakerslaying claim to chemical superlatives such as most explosive, most polar, or most twistedthat stake out new frontiers at the edges of chemical space. What drives researchers to set these records, and what impact does it have on their field? For some, it simply starts as a chemical challenge to make something more extreme than ever before. But working at the boundaries of chemistry can also spark deeper debates about fundamental ideas, such as the nature of bonding. And even when these record breakers have no immediate use, they open up new areas of investigation, tempting others to seek applications in previously unexplored regions of the molecular universe. Here, ACS Central Science looks at some recent record breakers and finds out how they are reshaping their corners of chemistry. Handle With Care " It's a rule in our lab not to make more than 5 g in one batch, " says Jö rg Stierstorfer of the Ludwig Maximilians University of Municha very sensible precaution, given that he spends his time as an assistant professor in Thomas Klapö tke's group making some of the world's most explosive chemicals. In 2011, Stierstorfer helped to create 1-diazidocarbamoyl-5-azidotetrazole (C 2 N 14), which has been widely described as the most explosive compound ever made. In this case, the superlative actually refers to the sensitivity of the compoundjust the lightest touch makes it go boom. That means it's difficult to say whether this is indeed the most sensitive explosive, Stierstorfer says, because his team cannot get near enough to measure the force needed to detonate it. Suffice to say, it's fearsome stuff. Yet Stierstorfer argues that their group has fewer injuries than a typical organic synthesis lab, thanks to the extensive precautions they take. They always wear face shields, Kevlar gloves, and other protective gear. And just in case things go wrong, right-handers carry explosive samples in their left hand, and vice versa. " We usually try to avoid making the most sensitive compounds, " Stierstorfer adds, largely because they are too ticklish for practical use. Instead, one of their main …