HEAVY-METAL RING BAGS METAL ATOM

Abstract

CHEMISTS have uncovered an unusual example of host-guest behavior in the form of a six-membered heterocyclic metal ring that traps and releases a neutral palladium atom. The research introduces heavy-metal heterocycles as a new class of compounds, and in reversibly trapping a neutral metal atom, the researchers add to the diversity of host-guest interactions ( J. Am. Chem. Soc., DOI: 10.1021/ja205515u). A team led by Richard D. Adams of the University of South Carolina, Columbia, and Michael B. Hall of Texas A&M University developed a process to make metallaheterocycles by linking heavy transition metals with heavy main-group bridging ligands such as diphenylantimony and diphenylbismuth and explained the nature of the host-guest binding. When the researchers took a three-membered Re 2 Sb heterocycle they made and heated it with a palladium catalyst, the Re 2 Sb ring dimerized to form a six-membered Re 4 Sb 2 heterocyclic ring. Under certain reaction conditions, the Re 4 Sb 2 ring trapped an unadorned pall...