This e-mail is to announce that Jeffrey Switzer will be defending his dissertation, Quantitative Kinetic Analysis of Olefin Polymerization by Single-Site Group IV Amine Bis-Phenolate Catalysts, on Thursday, August 14th , at 2:00PM in FRNY 3062A. The dissertation is being directed by Dr. Caruthers and Dr. Thomson, and the abstract is below. All are welcome to attend. Abstract: Polymerization by homogeneous single-site catalysts is a recent and growing area of research. While single-site catalysts are typically not as fast as heterogeneous ones, their major advantage is that the kinetic rate constants may be manipulated through precise changes to the catalyst structure and reaction conditions. Such a process yields tailored polymers not generally available through heterogeneous catalysis. Two breakthroughs are needed in this field in order to achieve this goal: (i) reliable rate constants must come from experimental data, and (ii) correlations between rate constants and chemical structure must be discovered. At present, the majority of new single-site catalysts are reported without detailed kinetic parameters, in part due to the complexity of simultaneously modeling all polymerization data. The purpose of this body of work is in part to discuss the complex process of kinetic modeling in the context of single-site polymerization in order to promote this activity by other researchers. To this end, kinetic modeling has been performed for a number of single-site catalyst systems. The Group IV amine bisphenolate catalysts studied are all similar in structure except for the metal (Zr or Hf) and the pendant donor arm (THF, pyridine, NMe2, furan, or SMe). The similar systems were chosen in order to probe how these small changes affect the kinetic rate constants. It was found that the donor arm has a large effect on the rate of chain transfer of the polymer, changing the rate by 1-2 orders of magnitude depending on the system. Meanwhile, the metal has a large effect on the propagation rate constant, with the rate constants in Zr faster than those in Hf by an order of magnitude. The temperature dependence of the rate constants was also examined for selected catalysts (Zr metal with THF, NMe2, and SMe pendants). The key findings were: (i) lower temperatures were discovered to prefer monomer dependent chain transfer while higher temperatures prefer monomer independent chain transfer, and (ii) reactions with sterically bulky active sites have high entropies but low enthalpies of activation, while less sterically hindered active sites have low entropies but high enthalpies of activation. These results allow for the possibility to manipulate the kinetic mechanism and can direct future catalyst and experiment design in order to engineer desired polymer products.