AEI 38 |
| The synthesis, structures and reactivity of (C5R5)2ZrR'(ClPh)+ chlorobenzene complexes were studied to understand halocarbon coordination to d0-metal LnMR'+ cations, which are active species in olefin polymerization and other reactions. (C5R5)2ZrR'(ClPh)+ complexes are thermally stable, only undergo minor photochemical reactions to form [{(C5R5)2Zr(μ-Cl)}2][B(C6F5)4]2 except in the case of sterically demanding C5Me5 (Cp*) ligand, in which ortho C-H activation of the bound ClPh occurs, followed by β-Cl elimination and benzyne insertion into a Zr-CCp* bond to afford [(η4,η1-C5Me5C6H4)Cp*ZrCl][B(C6F5)4]. The reaction of acrylonitrile (AN) with single-site olefin polymerization catalysts L2PdMe+ (L2= bis-imidazole, bis-pyridine and bis-immine ligands) were investigated to probe the feasibility of incorporating acrylonitrile as a monomer in insertion polymerization processes. These catalysts react with AN to form exclusive N-bound adduct, and inserts AN in a 2,1-fashion. The presence of α-cyano substituent causes aggregation and inhibition of further AN insertion by inter-molecular chelation to another Pd center. However, it does not prevent CO insertion, which proves that insertion polymerization of AN is possible. Cationic complexes CpM(CO)2(IMes)+ (IMes = 1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene, M = Mo, W) with weakly coordinating B(C6F5)4- counteranion were probed as active catalysts for hydrogenation and hydrosilylation of carbonyl compounds. Reactivity studies of these cationic complexes will be discussed to elucidate the mechanistic details of the catalytic cycle and major catalyst decomposition pathways. |
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Academic Employment Initiative
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix
Academic Employment Initiative |