TUNGSTEN BREAKS TOUGH BOND

Abstract

A STRONG AROMATIC carbon-carbon bond can be cleaved with ease by a tungsten complex that inserts the metal between the two carbon atoms, report chemists at Columbia University ( Nature 2010, 463, 523). The mechanism of this unusual bond breaking, which was observed in quinoxaline under mild conditions, could be extended to other systems, say the report's authors, opening new avenues for functionalizing aromatic molecules. Aaron Sattler and Gerard Parkin discovered the tungsten complex's bond-breaking ability while searching for a compound that would cleave C-N aromatic bonds. They had been working with molybdenum complexes but decided to switch to tungsten, which is a more aggressive metal. Sattler and Parkin were surprised to find that in the presence of the N-heterocylic molecule quinoxaline, the tungsten complex breaks the aromatic C-C bond adjacent to the aromatic C-N bond, even though the C-N bond, even though the C-N bond is typically more reactive. Carbon-carbon bond cleavage reactions are uncommo...