A 60-year search is over: Chemists isolate long-elusive molecules with boron-oxygen triple bonds

After 60 years of research, chemists have finally succeeded in isolating long-elusive molecules known as oxoboranes. The breakthrough discovery was made by a team led by professor Holger Braunschweig at the University of Würzburg, with supporting computational work from professor Ashwini K. Phukan at Tezpur University, India.

Oxoboranes, which contain boron-oxygen triple bonds, have been the focus of decades-long synthetic efforts by chemists worldwide. Despite years of attempts, stable oxoborane compounds remained elusive, with many chemists giving up on their isolation due to perceived instability.

The key to this breakthrough came from an unexpected reaction between a molecule called diboracumulene and various ketones, which are common organic chemistry reagents. When these two substances were combined, the reactions produced unusual orange or yellow solid products instead of the anticipated outcomes. Chemists Lukas Lubczyk and Christian Markl, both doctoral students in Würzburg's chemistry department, noticed this unusual result and worked together to analyze the compounds.

Braunschweig expressed surprise at the team's initial findings, stating that despite many other seemingly more likely outcomes, the oxoboranes were the main products of these reactions. This serendipitous discovery marked a significant milestone in the field, as nearly everyone had considered oxoboranes to be too unstable for isolation.

The team successfully prepared three isolable oxoboranes, confirming that the reaction method could produce a wide range of new oxoboranes in the future. The researchers are now exploring the possibilities of extending this method to prepare other elusive molecules across the periodic table.