Felix E. Goodson, Thomas I. Wallow, et al.
Macromolecules
The aryl-aryl interchange reaction of ArPdL2I complex 1m was found to follow pseudo-first-order kinetics. A marked inhibition in the presence of excess phosphine and/or excess iodide was observed, suggesting that a dissociative pathway was involved, contrary to the analogous alkyl-aryl interchange reaction studied previously. Phosphine flooding experiments could not be performed due to a competing phosphonium salt formation reaction that occurred in the presence of excess phosphine. A deuterium labeling experiment indicated that the interchange reaction proceeded via the reductive elimination to form the phosphonium salt, suggesting that excess phosphine was acting as a trap for intermediate palladium(0) species preventing the generation of the interchanged palladium-(II) complex. Substituent effect studies of the interchange reaction indicated that it was inhibited by electron-withdrawing groups on both the phosphine and palladium-bound aryl groups and by increased steric bulk on both the phosphine and palladium- bound aryl groups. Under catalytic conditions, the distribution of phosphines formed from the aryl-aryl interchange during palladium-mediated cross- coupling reactions could be modeled by statistics. Various strategies for eliminating the formation of byproducts caused by the interchange during cross-coupling reactions were screened and optimized.
Felix E. Goodson, Thomas I. Wallow, et al.
Macromolecules
Robert D. Allen, Juliann Opitz, et al.
Microlithography 1998
Felix E. Goodson, Thomas I. Wallow, et al.
Macromolecules
Juliann Opitz, Robert D. Allen, et al.
Microlithography 1998