Based on our long-standing Intensive Training Program for Effective Teaching Assistants in Chemistry, we have developed an Advanced Training Course for Teachers and Researchers in Chemistry at The University of Chicago. The topics in this course are designed to train graduate teaching assistants (GTAs) to become effective teachers and well-rounded PhD candidates.The goals of the course are to build ethics, critical thinking, and a positive self-image as a teacher through the use of a variety of pedagogical tools. Concurrently, the GTAs are transitioned into independent researchers with the skills to prepare written reports and oral presentations. The goals of this course were achieved based on the results of participant feedback. The experience gained and issues identified from the course may be used to guide future training courses.

The synthesis of the phosphine-cyclopentanesulfonate pro-ligands Li/K[2-PPh 2 -cyclopentanesulfonate] (Li/K[2a]), Li/K[2-P(2-OMe-Ph) 2 -cyclopentanesulfonate] (Li/K[2b]), and H[2b], and the corresponding Pd(II) alkyl complexes (κ 2 -P,O-2a)PdMe-(pyridine) (3a) and (κ 2 -P,O-2b)PdMe(pyridine) (3b) is described. The sulfonate-bridged base-free dimer {(2b)PdMe} 2 (4b) was synthesized by abstraction of pyridine from 3b using B(C 6 F 5 ) 3 . The borane-coordinated base-free dimer [{2b•B(C 6 F 5 ) 3 }PdMe] 2 (5b), in which B(C 6 F 5 ) 3 binds to a sulfonate oxygen, was prepared by addition of 1 equiv of B(C 6 F 5 ) 3 per Pd to 4b or addition of 2 equiv of B(C 6 F 5 ) 3 to 3b. Compounds 3b, 4b, and 5b polymerize ethylene with low activity (up to 210 kg mol −1 h −1 at 250 psi and 80 °C) to linear polyethylene (M n = 1950−5250 Da) with predominantly internal olefin placements. 3b and 4b copolymerize ethylene with methyl acrylate to linear copolymers that contain up to 11.7 mol % methyl acrylate, which is incorporated as −CH 2 CH(CO 2 Me)CH 2 − (80%) in-chain units and −CH 2 CH(CO 2 Me)Me (8%) and −CH 2 CHCH(CO 2 Me) (12%) chain-end units. 3b and 4b also copolymerize ethylene with vinyl fluoride to linear copolymers that contain up to 0.41 mol % vinyl fluoride, which is incorporated as −CH 2 CHFCH 2 − (∼80%) in-chain units and −CH 2 CF 2 H (7%), −CH 2 CHFCH 3 (5%), and −CH 2 CH 2 F (8%) chain-end units. Complexes 3b and 4b are more stable and active in ethylene polymerization than analogous (PAr 2 -CH 2 CH 2 SO 3 )PdR catalysts, but are less active than analogous (PAr 2 -arenesulfonate)PdR catalysts. Lowtemperature NMR studies show that 4b reacts with ethylene below −10 °C to form the ethylene adduct cis-P,R-(2b)PdMe(ethylene) (7b), which undergoes ethylene insertion at 5 °C. DFT calculations for a model (PMe 2cyclopentanesulfonate)Pd(Pr)(ethylene) species show that ethylene insertion proceeds by cis-P,R/trans-P,R isomerization followed by migratory insertion, and that the lower activity of 3b and 4b vis-a-vis analogous (PAr 2 -arenesulfonate)PdR catalysts results from a higher barrier for migratory insertion of the trans-P,R isomer.

The synthesis of the phosphine-arenesulfonate Pd­(II) fluoride complex (PO-OMe)­PdF­(lut) (2, PO-OMe = P­(2-OMe-Ph)2(2-SO3-5-Me-Ph), lut = 2,6-lutidine) and its reactions with electron-deficient olefins are described. The reaction of (PO-OMe)­PdBr­(lut) (1) with AgF affords 2 as an 82:18 mixture of cis-P,F and trans-P,F isomers. 2 isomerizes to a 1:2 cis-P,F:trans-P,F equilibrium mixture in CD2Cl2 solution at room temperature in ca. 3 days. 2 reacts with vinyl fluoride (VF) to afford (PO-OMe)­Pd­(CH2CHF2)­(lut) (3), which exists as the cis-P,C isomer. 2 reacts with vinyl bromide (VBr) to yield 1 and VF by initial fluoropalladation to form (PO-OMe)­Pd­(CH2CHBrF)­(lut) (4, not observed) followed by β-Br elimination. 2 reacts with vinyl acetate to yield (PO-OMe)­Pd­{CH2CHF­(OAc)}­(lut) (5), which reacts further to form the C-bound enolate complex (PO-OMe)­Pd­{CH2C­(O)­H}­(lut) (6) and acetyl fluoride. 2 reacts with vinyl benzoate in an analogous fashion. DFT analysis of the reaction of the model complexes cis-P,F- and trans-P,F-(PH2O)­PdF­(py) (C1 and C2, PH2O– = o-PH2C6H4SO3 –) with VF supports a mechanism involving substitution of lutidine by VF followed by migratory insertion into the Pd–F bond. An alternative mechanism comprising substitution of fluoride by VF to generate (PO-OMe)­Pd­(VF)­(lut)+ and F–, followed by exo attack of F– on the bound VF was found to be energetically prohibitive. DFT analysis of the reaction of the model complexes cis-P,F- and trans-P,F-(PH2O)­PdF­(VBr) (C10 and C13) supports an insertion/β-Br elimination mechanism.

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