AMMONIA IS READY FOR A TRANSFER

Abstract

THE DESIGN AND SYNTHESIS of an iridium complex that undergoes oxidative addition of ammonia to form an amido hydride derivative appears to have solved one of chemistry's long-standing research challenges: how to activate N-H bonds under mild conditions. This fundamental breakthrough could lead to industrially important catalytic ammonia-transfer processes. Chemists have known for a century that ammonia forms simple M-NH 3 coordination complexes with most transition metals. Transition-metal complexes also are known to insert into generally unreactive X-H bonds ofhydrogen, silanes, boranes, and alkanes (where X = H, Si, B, or C). But no one, until now, had designed a metal-ligand system that is thermodynamically favored to insert into an N-H bond of ammonia. Graduate student Jing Zhao and chemistry professor John F. Hartwig at Yale University along with chemistry professor Alan S. Goldman at Rutgers University, Piscataway N.J., have accomplished the feat with an iridium complex that contains a tridentate pi...