Use of alkynylphosphines for the regioselective formation of unsymmetrical zirconacyclopentadienes

INOR 845

Adam D. Miller, admiller@berkeley.edu1, Samuel Johnson, samj2@uclink.berkeley.edu1, Karl A. Tupper, tupperka@uclink.berkeley.edu1, Jennifer McBee, mcbee@berkeley.edu2, and T. Don Tilley1. (1) Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, (2) Department of Chemistry, UC Berkeley, Berkeley, CA 94720
Zirconacyclopentadienes, generated from the reductive coupling of alkynes by the Cp2Zr (zirconocene) fragment, have proven to be valuable intermediates for the synthesis of butadienes, substituted benzenes, and thiophenes, as well as conjugated polymers and macrocycles. As with any reaction, the utility increases with the ability to control the chemical, regio-, and stereoselectivities. It has been observed that diphenylphosphino groups will preferentially occupy the α-position upon formation of a zirconacyclopentadiene. We have discovered that when alkynylphosphines react with Cp2Zr a monoalkyne complex is formed which is useful for the regioselective formation of unsymmetrical zirconocyclopentadienes. These monoalkyne zirconocene sources can also be used in oligomer and polymer syntheses as capping groups which can be selectively substituted to increase the chain length in a step-wise fashion or to create block structures. This new synthetic methodology has the potential to improve traditional routes to conjugated oligomers and polymers.
 

Applications of Organometallic Chemistry
1:30 PM-4:40 PM, Wednesday, August 22, 2007 BCEC -- 205C, Oral

Division of Inorganic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007