8A Chemical Reviews, 2000, Vol. 100, No. 4
In Color on the Front Cover (Top) Space-filling model of a cationic Pd(II) complex with a (2,6-iPrPh)2DABH2 ligand after insertion of a methyl acrylate into a Pd−methyl bond, displaying the important steric protection provided by the ortho isopropyl groups on the DAB ligand. The noncoordinating [BAF]- counterion is also shown. See “Late Metal Catalysts for Ethylene Homo- and Copolymerization” by Steven D. Ittel, Lynda K. Johnson, and Maurice Brookhart, p 1169. (Bottom) Schematic illustration of a chiral, single-site metallocene catalyst forming isotactic polypropylene. See “Precise Control of Polyolefin Stereochemistry Using Single-Site Metal Catalysts” by Geoffrey W. Coates, p 1223. In Color on the Back Cover (Middle left) Model active sites for zirconium metallocene and nickel diimine olefin polymerization catalysts showing the preferred positioning of a model MAO counteranion. See “Modeling Metal Catalyzed Olefin Polymerization” by A. K. Rappe´, W. M. Skiff, and C. J. Casewit, p 1435. (Middle right) Syndiospecific methyl methacrylate polymerization mediated by a bimetallic metallocenium cation. See “Cocatalysts for Metal-Catalyzed Olefin Polymerization: Activators, Activation Processes, and Structure−Activity Relationships” by Eugene You-Xian Chen and Tobin J. Marks, p 1391. (Bottom right) Alkyne metathesis with Mo(CO)6/4-chlorophenol mixtures allows the facile synthesis of poly(p-phenyleneethynylene)s. Quantities of up to 20 g of PPE can be obtained in a 500 mL Schlenk flask. See “Polyarylene(ethynylene)s: Syntheses, Properties, Structures, and Applications” by Uwe H. F. Bunz, p 1605.
