The University of Würzburg reports in an account published by SciTechDaily that chemists led by Holger Braunschweig isolated three oxoboranes. The molecules contain an unusual triple bond between boron and oxygen, a combination long considered too unstable to isolate in a lasting form.
Chemists have pursued oxoboranes since at least the early 1960s. Earlier experiments detected or trapped them under extreme conditions, inferred their presence from reactions or produced related derivatives. The distinction in the university's account is the isolation of stable examples. “Nearly everybody in the field had given up on oxoboranes, as they were thought to be just too unstable to be isolated,” Braunschweig said.
The result was unexpected. Doctoral students Lukas Lubczyk and Christian Markl independently reacted a compound called a diboracumulene with different ketones and obtained orange or yellow solids. The university says oxoboranes were the main products. “The discovery was a pleasant surprise. I never thought the diboracumulene would react the way it did, let alone with multiple different, simple substrates,” Lubczyk said.
Ashwini K. Phukan's team at Tezpur University supported the work with computational research. Preparing three oxoboranes suggests the approach could produce more members of the molecular family, the university says. Researchers are investigating whether the method can be extended.
