Boron and beryllium finally shake hands

The first non-cluster bond between boron and beryllium has been reported by scientists in Germany.¹

10 years ago, few reactions existed where boron behaved as an nucleophile. That all changed with the advent of lithium diazaborolidein 2006,² and boron has been partnering up with myriad main-group, transition metal and lanthanide elements ever since. However, despite beryllium sitting right next to boron in the periodic table, a classical two-centre/two-electron bond had never been reported between the two neighbours, until now.

Holger Braunschweig and colleagues at the Julius Maximilians University of Würzburg have successfully synthesised a linear beryllium bis(diazaborolyl) compound by reacting lithium diazaborolide with beryllium chloride. It contains two highly polar covalent bonds between beryllium and boron, with the beryllium atom as the electrophilic centre – in contrast to the ionic bonding that is typical between lithium diazaborolide and other s-block elements, but in keeping with the established chemistry of beryllium.