where he obtained his M.S. degree in Organic Chemistry on asymmetric synthesis from Professor Dennis Liotta. He earned his Ph.D. degree in Polymer Chemistry in 1999 on controlled/"living" radical polymerization at Carnegie Mellon University under the direction of Professor Krzysztof Matyjaszewski. His current research interests include the controlled synthesis of novel polymeric materials.

Atom transfer radical addition, ATRA, is an efficient method for carbon-carbon bond formation in organic synthesis, and many benefits of this method are now well recognized.* 1 In some of these reactions, a transition-metal catalyst acts as a carrier of the halogen atom in a reversible redox process.2 Initially, the transition-metal species, M", abstracts halogen atom X from the organic halide, RX, to form the oxidized species, Mt"+1X, and the carbon-centered radical R\ In the subsequent step, the radical R" participates in an interor intramolecular radical addition to alkene, Y, with the formation of the intermediate radical species, RY*. The reaction between M"+1X and RY" results in a target product, RYX, and regenerates the reduced transition-metal species, M", which further promotes a new redox process. The fast reaction between RY' and Mtn+lX apparently suppresses bimolecular termination between alkyl radicals and efficiently introduces a halogen functional group X into the final product in good to excellent yields.2c~e

Current status and future perspectives in atom transfer radical polymerization (ATRP) are presented. Special emphasis is placed on mechanistic understanding of ATRP, recent synthetic and process development, and new controlled polymer architectures enabled by ATRP. New hybrid materials based on organic/inorganic systems and natural/synthetic polymers are presented. Some current and forthcoming applications are described.

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An extension of atom transfer radical addition, ATRA, to atom transfer radical polymerization, ATRP, provided a new and efficient way to conduct controlled/"living" radical polymerization. By using a simple alkyl halide, R-X (X = Cl and Br), as an initiator and a transition metal species complexed by suitable ligand(s), Mt"/L*, e.g., CuX/2,2'-bipyridine, as a catalyst, ATRP of vinyl monomers such as styrenes and (meth)acrylates proceeded in a living fashion, yielding polymers with degrees of polymerization predetermined by A[M]/[I]0 up to M" to 105 and low polydispersities, 1.1 < MJMn < 1.5. The participation of free radical intermediates was supported by analysis of the end groups and the stereochemistry of the polymerization. The general principle and the mechanism of ATRP are elucidated. Various factors affecting the ATRP process are discussed.